Applications of gamma ray spectrometry

A) Study of nuclear structure nuclear transitions and nuclear reactions

1) Properties and advantages of nuclear electromagnetic radiation studies 2) Facets of basic research by means of gamma spectroscopy 3) Basic methods a) Determination of level energies and decay scheme b) Measurement of level spins and parities transition multipolarities c) Measurement of transition probabilities (from level life time Coulomb excitation ) 4) Some interesting examples a) Study of states with very high spins ( very fast nuclear rotation) b) Superdeformed states c) Giant resonances 5) High energy bdquonuclearldquo spectrometry ndash example Study of neutral meson production in heavy ion collisions

B) Applications

1) Activation analysis 2) Material research by PIGE and PIXE methods 3) Usage of diffraction method at crystallography

Study of nuclear properties transitions and reactions

Unique properties of electromagnetic interactions

1) Simple well known description of interaction HEM

iEMf HEM )(Transition matrix element is

where ψi and ψf are wave functions of initial and final state

Transition probability rarr matrix element rarr direct information ψi and ψf

Main goal is to understand properties of system consists of finite number of stronglyinteracting particles (nucleons)

Properties of electromagnetic interactions and emission of photons during different nuclear processes are used

Observed gamma raysmake possible to study nuclear structure rarr understanding of strong interaction

2) Interaction energy of elmg interaction at nucleus is given by hadron electric charges and their electric currents (given by charged hadron motion and magnetic momenta of all hadrons)

where trAtr is four-vector of potential and

tr

c

jtr

four-vector of charge current

Assumption nucleus ndash system of point like nucleons

ii

iz rrter

2

1Charge density

Current density

Interaction of nucleonMagnetic momenta where

- nuclear magneton

Motion of chargednucleons

114

Nj MeVT10153

c2m

e

where is isospin projection (convention is tz proton = +12 and neutron -12) vi velocity and si spin

izt

102

1gtgg i

zis

iii

isjiiii

iz

i

rrsgcvrrrrvterj

2

1

2

1

gyromagnetic ratios g0 = gp + gn a g1 = gn ndash gp proton gp = 558neutron gn = - 382

rdtrAtrjc

rdtrtrH EM33

1

Study of elmg interaction ndash direct test charge distribution velocities of nucleons nuclear spins and izospins

3) Weak interaction constant ndash α = 1137 application of perturbative methods mostly first order is sufficient higher orders are necessary only in the case of suppression of first order transition by conservation laws or selection rule

Clean radiation field at vacuum (φ = 0)

Maxwell equations are fulfilled rarr 0)(1

2

2

22

trAtc

0 trAdiv

Common vector field is possible express by arbitrary complete set of ortoghonal solutions of these equations We will use

where 122

cck

Maxwel equations are equivalent to 00 22 kkkk AkAAkA

t

A

cE

1 AH

Intensities of electricand magnetic field

4) Simple multiple expansion and selection rules

This equation is satisfied (J and M are integer numbers) by

and

We can resolve arbitrary to set of these solutions (P = E or M)

))]()(([

JMJEJM Ykrjr

k

iA

))()(( JMJ

MJM YkrjrA

)( JMY

A

rAeqtrA kti

k

rkAeqdktrA PJM

tiJMPk

PMJ

AΔAA

Reminder

= 0

where jJ(kr) ndash spherical Bessel function and - normalized spherical harmonic function

Approximation 1) Nucleon motion is nonrelativistic 2) Radiation wave length is long against nuclear radius

MeVAAm

mssMeV

Ar

c

R

cE

E

cR

j

31

3115

1822

31

0

1641021

10310586

A Eγ ltlt [MeV]50 45100 35200 28

11

kRk

RR

Selection rules

Quantum field rarr Eγ = ħω component z of momentum Mħ qq ndash operator with eigenvalue of photon number

Long wave approximation )12(

)()(

J

krkrj

J

J

Photon has spin I and parity π EJ rarr I = min J π = (-1)I

MJ rarr I = min J π = (-1)I+1

rarr members with the lowest J value ( )

Transition between levels with spins Ii and If and parities πi and πf

I = |Ii ndash If| for Ii ne If I = 1 for Ii = If gt 0 π = (-1)I+K = πiπf K=0 for E and K=1 for MElectromagnetic transition with photon emission between states Ii = 0 and If = 0 donacutet exist

MeV

E

c

Ek

197

Studies using gamma ray and electron spectrometry

1) Basic properties of nuclei ndash quantum system of strongly interacting nucleons new nuclear shapes highly excited particle and hole states electromagnetic response (spin izospin ) different collective states

2) Nucleon motion in extreme conditions ndash high excitation high spins (rotation) superdeformed states giant dipole resonances

3) Study of fundamental symmetries of elementary particles inside hadron system new degree of freedoms at nuclear field resonance and strangeness production parton degrees of freedom

Spectrometer EXOGAMon beam of radioactive beam at GANIL (France)

Photon spectrometerTAPS during its first stay at GANIL

Determination level energies and decay scheme construction

1) As accurate determination of transition energy as possible

2) Coincidence measurements ndash determination of transition placement at cascade (intrinsic geometry of anticompton spectrometer and multidetector set-ups)

Spectrum and decay scheme from 166mHo decay study performed by means of anticomptonSpectrometer of NPI of ASCR ndash focused on weak transition with high energy deexcitating rotational bands on vibrational states

3) Level energies from reactions

Determination of level spins and transition multipolarities

1) Usage of electromagnetic transition selection rules ndash usage of selection rules and knowledge about spin of some level which transition connects

2) Usage of ratios between probabilities of gamma transition and emission of conversion electronldquo

3) Usage of angular distribution of gamma rays against nuclear spin

4) Angular correlation of two photons emitted in sequence at cascade

5) Information about spins from reactions analysis of different reaction histories ndash different reactions excite levels with different spins

Determination of transition conversion coefficient

N

Ne

Conversion coefficients for separate shells αK αL αM αN

Properties 1) Conversion coefficients increase with increasing of transition multipolarity 2) α(M) gt α(E) 3) fast decreasing with transition energy

Dependency of total conversion coefficients on transition energysketchy picture (values taken from ADNDT 21(1978)4-5)

Oriented nuclei ndash study of angular distributionOrientation by magnetic field preferred direction of beam in reaction

)(cosacute))()(()()(

PJMEJMEIIfIW f

n

ii

Legendrepolynomials

Spin orientationintensity

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Study of nuclear properties transitions and reactions

Unique properties of electromagnetic interactions

1) Simple well known description of interaction HEM

iEMf HEM )(Transition matrix element is

where ψi and ψf are wave functions of initial and final state

Transition probability rarr matrix element rarr direct information ψi and ψf

Main goal is to understand properties of system consists of finite number of stronglyinteracting particles (nucleons)

Properties of electromagnetic interactions and emission of photons during different nuclear processes are used

Observed gamma raysmake possible to study nuclear structure rarr understanding of strong interaction

2) Interaction energy of elmg interaction at nucleus is given by hadron electric charges and their electric currents (given by charged hadron motion and magnetic momenta of all hadrons)

where trAtr is four-vector of potential and

tr

c

jtr

four-vector of charge current

Assumption nucleus ndash system of point like nucleons

ii

iz rrter

2

1Charge density

Current density

Interaction of nucleonMagnetic momenta where

- nuclear magneton

Motion of chargednucleons

114

Nj MeVT10153

c2m

e

where is isospin projection (convention is tz proton = +12 and neutron -12) vi velocity and si spin

izt

102

1gtgg i

zis

iii

isjiiii

iz

i

rrsgcvrrrrvterj

2

1

2

1

gyromagnetic ratios g0 = gp + gn a g1 = gn ndash gp proton gp = 558neutron gn = - 382

rdtrAtrjc

rdtrtrH EM33

1

Study of elmg interaction ndash direct test charge distribution velocities of nucleons nuclear spins and izospins

3) Weak interaction constant ndash α = 1137 application of perturbative methods mostly first order is sufficient higher orders are necessary only in the case of suppression of first order transition by conservation laws or selection rule

Clean radiation field at vacuum (φ = 0)

Maxwell equations are fulfilled rarr 0)(1

2

2

22

trAtc

0 trAdiv

Common vector field is possible express by arbitrary complete set of ortoghonal solutions of these equations We will use

where 122

cck

Maxwel equations are equivalent to 00 22 kkkk AkAAkA

t

A

cE

1 AH

Intensities of electricand magnetic field

4) Simple multiple expansion and selection rules

This equation is satisfied (J and M are integer numbers) by

and

We can resolve arbitrary to set of these solutions (P = E or M)

))]()(([

JMJEJM Ykrjr

k

iA

))()(( JMJ

MJM YkrjrA

)( JMY

A

rAeqtrA kti

k

rkAeqdktrA PJM

tiJMPk

PMJ

AΔAA

Reminder

= 0

where jJ(kr) ndash spherical Bessel function and - normalized spherical harmonic function

Approximation 1) Nucleon motion is nonrelativistic 2) Radiation wave length is long against nuclear radius

MeVAAm

mssMeV

Ar

c

R

cE

E

cR

j

31

3115

1822

31

0

1641021

10310586

A Eγ ltlt [MeV]50 45100 35200 28

11

kRk

RR

Selection rules

Quantum field rarr Eγ = ħω component z of momentum Mħ qq ndash operator with eigenvalue of photon number

Long wave approximation )12(

)()(

J

krkrj

J

J

Photon has spin I and parity π EJ rarr I = min J π = (-1)I

MJ rarr I = min J π = (-1)I+1

rarr members with the lowest J value ( )

Transition between levels with spins Ii and If and parities πi and πf

I = |Ii ndash If| for Ii ne If I = 1 for Ii = If gt 0 π = (-1)I+K = πiπf K=0 for E and K=1 for MElectromagnetic transition with photon emission between states Ii = 0 and If = 0 donacutet exist

MeV

E

c

Ek

197

Studies using gamma ray and electron spectrometry

1) Basic properties of nuclei ndash quantum system of strongly interacting nucleons new nuclear shapes highly excited particle and hole states electromagnetic response (spin izospin ) different collective states

2) Nucleon motion in extreme conditions ndash high excitation high spins (rotation) superdeformed states giant dipole resonances

3) Study of fundamental symmetries of elementary particles inside hadron system new degree of freedoms at nuclear field resonance and strangeness production parton degrees of freedom

Spectrometer EXOGAMon beam of radioactive beam at GANIL (France)

Photon spectrometerTAPS during its first stay at GANIL

Determination level energies and decay scheme construction

1) As accurate determination of transition energy as possible

2) Coincidence measurements ndash determination of transition placement at cascade (intrinsic geometry of anticompton spectrometer and multidetector set-ups)

Spectrum and decay scheme from 166mHo decay study performed by means of anticomptonSpectrometer of NPI of ASCR ndash focused on weak transition with high energy deexcitating rotational bands on vibrational states

3) Level energies from reactions

Determination of level spins and transition multipolarities

1) Usage of electromagnetic transition selection rules ndash usage of selection rules and knowledge about spin of some level which transition connects

2) Usage of ratios between probabilities of gamma transition and emission of conversion electronldquo

3) Usage of angular distribution of gamma rays against nuclear spin

4) Angular correlation of two photons emitted in sequence at cascade

5) Information about spins from reactions analysis of different reaction histories ndash different reactions excite levels with different spins

Determination of transition conversion coefficient

N

Ne

Conversion coefficients for separate shells αK αL αM αN

Properties 1) Conversion coefficients increase with increasing of transition multipolarity 2) α(M) gt α(E) 3) fast decreasing with transition energy

Dependency of total conversion coefficients on transition energysketchy picture (values taken from ADNDT 21(1978)4-5)

Oriented nuclei ndash study of angular distributionOrientation by magnetic field preferred direction of beam in reaction

)(cosacute))()(()()(

PJMEJMEIIfIW f

n

ii

Legendrepolynomials

Spin orientationintensity

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

2) Interaction energy of elmg interaction at nucleus is given by hadron electric charges and their electric currents (given by charged hadron motion and magnetic momenta of all hadrons)

where trAtr is four-vector of potential and

tr

c

jtr

four-vector of charge current

Assumption nucleus ndash system of point like nucleons

ii

iz rrter

2

1Charge density

Current density

Interaction of nucleonMagnetic momenta where

- nuclear magneton

Motion of chargednucleons

114

Nj MeVT10153

c2m

e

where is isospin projection (convention is tz proton = +12 and neutron -12) vi velocity and si spin

izt

102

1gtgg i

zis

iii

isjiiii

iz

i

rrsgcvrrrrvterj

2

1

2

1

gyromagnetic ratios g0 = gp + gn a g1 = gn ndash gp proton gp = 558neutron gn = - 382

rdtrAtrjc

rdtrtrH EM33

1

Study of elmg interaction ndash direct test charge distribution velocities of nucleons nuclear spins and izospins

3) Weak interaction constant ndash α = 1137 application of perturbative methods mostly first order is sufficient higher orders are necessary only in the case of suppression of first order transition by conservation laws or selection rule

Clean radiation field at vacuum (φ = 0)

Maxwell equations are fulfilled rarr 0)(1

2

2

22

trAtc

0 trAdiv

Common vector field is possible express by arbitrary complete set of ortoghonal solutions of these equations We will use

where 122

cck

Maxwel equations are equivalent to 00 22 kkkk AkAAkA

t

A

cE

1 AH

Intensities of electricand magnetic field

4) Simple multiple expansion and selection rules

This equation is satisfied (J and M are integer numbers) by

and

We can resolve arbitrary to set of these solutions (P = E or M)

))]()(([

JMJEJM Ykrjr

k

iA

))()(( JMJ

MJM YkrjrA

)( JMY

A

rAeqtrA kti

k

rkAeqdktrA PJM

tiJMPk

PMJ

AΔAA

Reminder

= 0

where jJ(kr) ndash spherical Bessel function and - normalized spherical harmonic function

Approximation 1) Nucleon motion is nonrelativistic 2) Radiation wave length is long against nuclear radius

MeVAAm

mssMeV

Ar

c

R

cE

E

cR

j

31

3115

1822

31

0

1641021

10310586

A Eγ ltlt [MeV]50 45100 35200 28

11

kRk

RR

Selection rules

Quantum field rarr Eγ = ħω component z of momentum Mħ qq ndash operator with eigenvalue of photon number

Long wave approximation )12(

)()(

J

krkrj

J

J

Photon has spin I and parity π EJ rarr I = min J π = (-1)I

MJ rarr I = min J π = (-1)I+1

rarr members with the lowest J value ( )

Transition between levels with spins Ii and If and parities πi and πf

I = |Ii ndash If| for Ii ne If I = 1 for Ii = If gt 0 π = (-1)I+K = πiπf K=0 for E and K=1 for MElectromagnetic transition with photon emission between states Ii = 0 and If = 0 donacutet exist

MeV

E

c

Ek

197

Studies using gamma ray and electron spectrometry

1) Basic properties of nuclei ndash quantum system of strongly interacting nucleons new nuclear shapes highly excited particle and hole states electromagnetic response (spin izospin ) different collective states

2) Nucleon motion in extreme conditions ndash high excitation high spins (rotation) superdeformed states giant dipole resonances

3) Study of fundamental symmetries of elementary particles inside hadron system new degree of freedoms at nuclear field resonance and strangeness production parton degrees of freedom

Spectrometer EXOGAMon beam of radioactive beam at GANIL (France)

Photon spectrometerTAPS during its first stay at GANIL

Determination level energies and decay scheme construction

1) As accurate determination of transition energy as possible

2) Coincidence measurements ndash determination of transition placement at cascade (intrinsic geometry of anticompton spectrometer and multidetector set-ups)

Spectrum and decay scheme from 166mHo decay study performed by means of anticomptonSpectrometer of NPI of ASCR ndash focused on weak transition with high energy deexcitating rotational bands on vibrational states

3) Level energies from reactions

Determination of level spins and transition multipolarities

1) Usage of electromagnetic transition selection rules ndash usage of selection rules and knowledge about spin of some level which transition connects

2) Usage of ratios between probabilities of gamma transition and emission of conversion electronldquo

3) Usage of angular distribution of gamma rays against nuclear spin

4) Angular correlation of two photons emitted in sequence at cascade

5) Information about spins from reactions analysis of different reaction histories ndash different reactions excite levels with different spins

Determination of transition conversion coefficient

N

Ne

Conversion coefficients for separate shells αK αL αM αN

Properties 1) Conversion coefficients increase with increasing of transition multipolarity 2) α(M) gt α(E) 3) fast decreasing with transition energy

Dependency of total conversion coefficients on transition energysketchy picture (values taken from ADNDT 21(1978)4-5)

Oriented nuclei ndash study of angular distributionOrientation by magnetic field preferred direction of beam in reaction

)(cosacute))()(()()(

PJMEJMEIIfIW f

n

ii

Legendrepolynomials

Spin orientationintensity

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

3) Weak interaction constant ndash α = 1137 application of perturbative methods mostly first order is sufficient higher orders are necessary only in the case of suppression of first order transition by conservation laws or selection rule

Clean radiation field at vacuum (φ = 0)

Maxwell equations are fulfilled rarr 0)(1

2

2

22

trAtc

0 trAdiv

Common vector field is possible express by arbitrary complete set of ortoghonal solutions of these equations We will use

where 122

cck

Maxwel equations are equivalent to 00 22 kkkk AkAAkA

t

A

cE

1 AH

Intensities of electricand magnetic field

4) Simple multiple expansion and selection rules

This equation is satisfied (J and M are integer numbers) by

and

We can resolve arbitrary to set of these solutions (P = E or M)

))]()(([

JMJEJM Ykrjr

k

iA

))()(( JMJ

MJM YkrjrA

)( JMY

A

rAeqtrA kti

k

rkAeqdktrA PJM

tiJMPk

PMJ

AΔAA

Reminder

= 0

where jJ(kr) ndash spherical Bessel function and - normalized spherical harmonic function

Approximation 1) Nucleon motion is nonrelativistic 2) Radiation wave length is long against nuclear radius

MeVAAm

mssMeV

Ar

c

R

cE

E

cR

j

31

3115

1822

31

0

1641021

10310586

A Eγ ltlt [MeV]50 45100 35200 28

11

kRk

RR

Selection rules

Quantum field rarr Eγ = ħω component z of momentum Mħ qq ndash operator with eigenvalue of photon number

Long wave approximation )12(

)()(

J

krkrj

J

J

Photon has spin I and parity π EJ rarr I = min J π = (-1)I

MJ rarr I = min J π = (-1)I+1

rarr members with the lowest J value ( )

Transition between levels with spins Ii and If and parities πi and πf

I = |Ii ndash If| for Ii ne If I = 1 for Ii = If gt 0 π = (-1)I+K = πiπf K=0 for E and K=1 for MElectromagnetic transition with photon emission between states Ii = 0 and If = 0 donacutet exist

MeV

E

c

Ek

197

Studies using gamma ray and electron spectrometry

1) Basic properties of nuclei ndash quantum system of strongly interacting nucleons new nuclear shapes highly excited particle and hole states electromagnetic response (spin izospin ) different collective states

2) Nucleon motion in extreme conditions ndash high excitation high spins (rotation) superdeformed states giant dipole resonances

3) Study of fundamental symmetries of elementary particles inside hadron system new degree of freedoms at nuclear field resonance and strangeness production parton degrees of freedom

Spectrometer EXOGAMon beam of radioactive beam at GANIL (France)

Photon spectrometerTAPS during its first stay at GANIL

Determination level energies and decay scheme construction

1) As accurate determination of transition energy as possible

2) Coincidence measurements ndash determination of transition placement at cascade (intrinsic geometry of anticompton spectrometer and multidetector set-ups)

Spectrum and decay scheme from 166mHo decay study performed by means of anticomptonSpectrometer of NPI of ASCR ndash focused on weak transition with high energy deexcitating rotational bands on vibrational states

3) Level energies from reactions

Determination of level spins and transition multipolarities

1) Usage of electromagnetic transition selection rules ndash usage of selection rules and knowledge about spin of some level which transition connects

2) Usage of ratios between probabilities of gamma transition and emission of conversion electronldquo

3) Usage of angular distribution of gamma rays against nuclear spin

4) Angular correlation of two photons emitted in sequence at cascade

5) Information about spins from reactions analysis of different reaction histories ndash different reactions excite levels with different spins

Determination of transition conversion coefficient

N

Ne

Conversion coefficients for separate shells αK αL αM αN

Properties 1) Conversion coefficients increase with increasing of transition multipolarity 2) α(M) gt α(E) 3) fast decreasing with transition energy

Dependency of total conversion coefficients on transition energysketchy picture (values taken from ADNDT 21(1978)4-5)

Oriented nuclei ndash study of angular distributionOrientation by magnetic field preferred direction of beam in reaction

)(cosacute))()(()()(

PJMEJMEIIfIW f

n

ii

Legendrepolynomials

Spin orientationintensity

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Approximation 1) Nucleon motion is nonrelativistic 2) Radiation wave length is long against nuclear radius

MeVAAm

mssMeV

Ar

c

R

cE

E

cR

j

31

3115

1822

31

0

1641021

10310586

A Eγ ltlt [MeV]50 45100 35200 28

11

kRk

RR

Selection rules

Quantum field rarr Eγ = ħω component z of momentum Mħ qq ndash operator with eigenvalue of photon number

Long wave approximation )12(

)()(

J

krkrj

J

J

Photon has spin I and parity π EJ rarr I = min J π = (-1)I

MJ rarr I = min J π = (-1)I+1

rarr members with the lowest J value ( )

Transition between levels with spins Ii and If and parities πi and πf

I = |Ii ndash If| for Ii ne If I = 1 for Ii = If gt 0 π = (-1)I+K = πiπf K=0 for E and K=1 for MElectromagnetic transition with photon emission between states Ii = 0 and If = 0 donacutet exist

MeV

E

c

Ek

197

Studies using gamma ray and electron spectrometry

1) Basic properties of nuclei ndash quantum system of strongly interacting nucleons new nuclear shapes highly excited particle and hole states electromagnetic response (spin izospin ) different collective states

2) Nucleon motion in extreme conditions ndash high excitation high spins (rotation) superdeformed states giant dipole resonances

3) Study of fundamental symmetries of elementary particles inside hadron system new degree of freedoms at nuclear field resonance and strangeness production parton degrees of freedom

Spectrometer EXOGAMon beam of radioactive beam at GANIL (France)

Photon spectrometerTAPS during its first stay at GANIL

Determination level energies and decay scheme construction

1) As accurate determination of transition energy as possible

2) Coincidence measurements ndash determination of transition placement at cascade (intrinsic geometry of anticompton spectrometer and multidetector set-ups)

Spectrum and decay scheme from 166mHo decay study performed by means of anticomptonSpectrometer of NPI of ASCR ndash focused on weak transition with high energy deexcitating rotational bands on vibrational states

3) Level energies from reactions

Determination of level spins and transition multipolarities

1) Usage of electromagnetic transition selection rules ndash usage of selection rules and knowledge about spin of some level which transition connects

2) Usage of ratios between probabilities of gamma transition and emission of conversion electronldquo

3) Usage of angular distribution of gamma rays against nuclear spin

4) Angular correlation of two photons emitted in sequence at cascade

5) Information about spins from reactions analysis of different reaction histories ndash different reactions excite levels with different spins

Determination of transition conversion coefficient

N

Ne

Conversion coefficients for separate shells αK αL αM αN

Properties 1) Conversion coefficients increase with increasing of transition multipolarity 2) α(M) gt α(E) 3) fast decreasing with transition energy

Dependency of total conversion coefficients on transition energysketchy picture (values taken from ADNDT 21(1978)4-5)

Oriented nuclei ndash study of angular distributionOrientation by magnetic field preferred direction of beam in reaction

)(cosacute))()(()()(

PJMEJMEIIfIW f

n

ii

Legendrepolynomials

Spin orientationintensity

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Studies using gamma ray and electron spectrometry

1) Basic properties of nuclei ndash quantum system of strongly interacting nucleons new nuclear shapes highly excited particle and hole states electromagnetic response (spin izospin ) different collective states

2) Nucleon motion in extreme conditions ndash high excitation high spins (rotation) superdeformed states giant dipole resonances

3) Study of fundamental symmetries of elementary particles inside hadron system new degree of freedoms at nuclear field resonance and strangeness production parton degrees of freedom

Spectrometer EXOGAMon beam of radioactive beam at GANIL (France)

Photon spectrometerTAPS during its first stay at GANIL

Determination level energies and decay scheme construction

1) As accurate determination of transition energy as possible

2) Coincidence measurements ndash determination of transition placement at cascade (intrinsic geometry of anticompton spectrometer and multidetector set-ups)

Spectrum and decay scheme from 166mHo decay study performed by means of anticomptonSpectrometer of NPI of ASCR ndash focused on weak transition with high energy deexcitating rotational bands on vibrational states

3) Level energies from reactions

Determination of level spins and transition multipolarities

1) Usage of electromagnetic transition selection rules ndash usage of selection rules and knowledge about spin of some level which transition connects

2) Usage of ratios between probabilities of gamma transition and emission of conversion electronldquo

3) Usage of angular distribution of gamma rays against nuclear spin

4) Angular correlation of two photons emitted in sequence at cascade

5) Information about spins from reactions analysis of different reaction histories ndash different reactions excite levels with different spins

Determination of transition conversion coefficient

N

Ne

Conversion coefficients for separate shells αK αL αM αN

Properties 1) Conversion coefficients increase with increasing of transition multipolarity 2) α(M) gt α(E) 3) fast decreasing with transition energy

Dependency of total conversion coefficients on transition energysketchy picture (values taken from ADNDT 21(1978)4-5)

Oriented nuclei ndash study of angular distributionOrientation by magnetic field preferred direction of beam in reaction

)(cosacute))()(()()(

PJMEJMEIIfIW f

n

ii

Legendrepolynomials

Spin orientationintensity

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Determination level energies and decay scheme construction

1) As accurate determination of transition energy as possible

2) Coincidence measurements ndash determination of transition placement at cascade (intrinsic geometry of anticompton spectrometer and multidetector set-ups)

Spectrum and decay scheme from 166mHo decay study performed by means of anticomptonSpectrometer of NPI of ASCR ndash focused on weak transition with high energy deexcitating rotational bands on vibrational states

3) Level energies from reactions

Determination of level spins and transition multipolarities

1) Usage of electromagnetic transition selection rules ndash usage of selection rules and knowledge about spin of some level which transition connects

2) Usage of ratios between probabilities of gamma transition and emission of conversion electronldquo

3) Usage of angular distribution of gamma rays against nuclear spin

4) Angular correlation of two photons emitted in sequence at cascade

5) Information about spins from reactions analysis of different reaction histories ndash different reactions excite levels with different spins

Determination of transition conversion coefficient

N

Ne

Conversion coefficients for separate shells αK αL αM αN

Properties 1) Conversion coefficients increase with increasing of transition multipolarity 2) α(M) gt α(E) 3) fast decreasing with transition energy

Dependency of total conversion coefficients on transition energysketchy picture (values taken from ADNDT 21(1978)4-5)

Oriented nuclei ndash study of angular distributionOrientation by magnetic field preferred direction of beam in reaction

)(cosacute))()(()()(

PJMEJMEIIfIW f

n

ii

Legendrepolynomials

Spin orientationintensity

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Determination of level spins and transition multipolarities

1) Usage of electromagnetic transition selection rules ndash usage of selection rules and knowledge about spin of some level which transition connects

2) Usage of ratios between probabilities of gamma transition and emission of conversion electronldquo

3) Usage of angular distribution of gamma rays against nuclear spin

4) Angular correlation of two photons emitted in sequence at cascade

5) Information about spins from reactions analysis of different reaction histories ndash different reactions excite levels with different spins

Determination of transition conversion coefficient

N

Ne

Conversion coefficients for separate shells αK αL αM αN

Properties 1) Conversion coefficients increase with increasing of transition multipolarity 2) α(M) gt α(E) 3) fast decreasing with transition energy

Dependency of total conversion coefficients on transition energysketchy picture (values taken from ADNDT 21(1978)4-5)

Oriented nuclei ndash study of angular distributionOrientation by magnetic field preferred direction of beam in reaction

)(cosacute))()(()()(

PJMEJMEIIfIW f

n

ii

Legendrepolynomials

Spin orientationintensity

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Determination of transition probabilities using life time of levels

1) Electronic methods ndash measurement of decay curve

Resolution of BaF2 - ~ 100 psResolution of reaction time (often from accelerator RF) ~ 1 nsTotal resolution in the order from units up to parts of ns

Time spectrum ndash gauss (prompt) + exponential curve (isomer)

Available the lowest limit τ ~ ns = 10-9s

Isomere state measurement

Off beam measurement (after irradiation) τ ~ min - infin

Transport system and measurement during irradiation τ gt ~ s

On beam measurements

Modification of time spectrumfor τ comparable with FWHM

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

2) Usage of Doppler shift

Velocity of compound nucleus

A) We use study of ratio of Doppler shifted and not shifted lines intensities as function of distance in which reflected nuclei are stopped

Compound nucleus is created during reaction a(AC)

Velocity of reflected nucleus depends on reaction kinematics in the case of Coulomb excitation and direct reaction

Energy of photon emitted by moving nucleus

where θ ndash angle between directions of nucleus motion and photon emission

Dependency of ratio EγEγ0 = f(θ)Resolution HPGE ~ 0003and scintillator ~ 005

2

22

cMm

Ecm

c

v

Mm

mvv

Aa

kinaaC

Aa

aaĆ

cos10 c

vEE

c

v

E

E

0

max

for θ = 0o and 180o is energy difference maximal

Dependency of compound nucleus velocity on beam energy

PS

S

SS

SdR

)(

0

)0(t

tS dteSS

0

0

)0(t t

P dteSS

Ratio of intensities emitted by reflected nuclei

in motion and stopped

where d = vt0 is distance between targetand foil which is stopping reflected nuclei

v ltlt c rarr omission of member with (vc)2

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Measurable life time range τ ~ 10-12 ndash 10-15s

B) Doppler shift attenuation method

Production of reflected nuclei rarr deceleration and scattering inside target or thinplate rarr emitted photon has different Doppler shift of energy rarr complicated shape of line

Measurable life time range τ ~ 10-10 ndash 10-12 s

Line shape analysis rarr determination of level life time

Distances d in the range 1 ndash 10-2 mm (distance is measured electrically)

Example of measurement of gamma lines from levels with different life time

Relation of ionization losses and path Δx = (dEdx)-1ΔE

Path for measurable change of velocity or stopping depends on Z of reflected nucleus and target material but x lt 10-2 mm

Problems 1) Description of deceleration and multiple scattering of reflected nucleus 2) Life time of previous transition in the cascade

Target 07 ndash 15 μm foil 5- 10 μm Au Ta Bi

Example of Doppler shift attenuation measurement (takenfrom D Poenaru W GreinerExperimental Techniquesin Nuclear Physics)

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Determination of transition probabilities using Coulomb excitation

Heavy ion beams are used rarr high charge rarr excitation of states with high spin

)(~

31

23

1

1

21

AA

ZZECB

Energy can not be higher then Coulomb barrier energy

where Z1 Z2 A1 a A2 are parameters of beam and target nuclei

Advantageous 1) Clean electromagnetic process 2) Minimal background ndash without nuclear reactions on target or surrounding material 3) Dominant excitation by E2 transitions (vc relatively small rarr B(M) ltlt B(E) E1 suppressed B(EI)gtgtB(EI+1) for I gt 1) rarr excitation of rotational bands with E2 transitions 4) Possibility of choice of case with excitation to spin state harr large projectile scattering angle ndash common detection of scattered projectile reflected nucleus and gamma quantas

Connection of Coulomb excitation life time measurements and magnetic momenta determination

Further methods Nuclear resonance fluorescencendash usage of Mőssbauer phenomena τ = 10-17 -10-14 s proton resonance τ lt 10-16 s

Measurable life times τ = 10-13 -10-9 s

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Studies of states with very high spin

Excitation of high spin states by heavy ion collisions

(Spins Iħ ge 40ħ)

Study is possible by 4PI multi detector spectrometers

Compound nucleus creation (τ gt 10-20s) ndash 1) nuclei with big proton excess 2) radioactive nuclei beam ndash also nuclei with neutron excess

Usage of Coulomb excitation

Excitation energy EEX = ECM + Q

CCMMAX VER

l 2

22 2

Maximal achievable spin

μ ndash reduced mass of colliding nucleiR ndash the biggest distance which can be possible for compound nucleus creation

Approximation partial wave only up to lMAX

Maximal spin of stable rotating nucleus (classical estimates)

Superdefor-med states

Projectile energy in CM

Reaction energy

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Yrast line ndash connects states with the highest spin for given energy

After compound nucleus creation evaporation of some Nucleons (especially neutrons) rarr fast energy decrease ~ 8 MeVn only small decrease of angular momenta ~ 1ħn

Excitation energy is lower than separation energy rarr 10-15s deexcitation by gamma quants1) Statistical (starting at high state density) E1 transitions from the highest excitated states2) E2 transitions near to Yrast line ndash not only inside rotational bands (because of crossing) rarr high number of transitions with small intensity ndash bdquoquasicontinuumldquo3) Regular structure of rotational bands ~ 1MeV above Yrast line rarr sufficient intensity rarr observation of single transitions

Deexcitation of compoundNucleus with very highspin (rotation) (taken fromD Poenaru W GreinerExperimental Techniquesin Nuclear Physics]

Total deexcitation time ~ 10-9s number of emitted photons ~ 30

competitive high energy gamma depopulating giant dipole resonances

Two type of rotation 1) Collective rotation ndash region of deformed nuclei ndash collective motion of many nucleons 2) Noncollective rotation ndash spherical and weakly deformed nuclei ndash high spin given by motion of a few nucleons

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Superdeformed states

States with very high deformation (axis ratio 21 and more)

High spins - transitions between single types of rotation with drastic changes of nucleus shapeHamiltonian for rotation of axially symmetrical nucleus

Adiabatic condition ndash rotation is slow against singleparticle motion and vibrations rarr Hintr and Hvib

Are separated

High spins ndash fast rotation rarr strong Coriolis interaction between particle and rotational motion

vibr HHJIH

int

2

2

Band crossing ndash strong Coriolis interaction decrease energy of excited singleparticle state above which rotational band develops rarr crossing with band above ground state

Long rotational bands deexcitated by long cascades of E2 transitions with very near energies

High spins ~ 40 - 70 first nucleus 152Dy (1984)

Example of rotational bands in situation of adiabatic approximation

Predicted by shell model ndash spacing between shells for deformed potential

Only small probability of such state population ~ 1

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Giant resonances

Different types of giant resonances (taken from WWW pages of GANIL)

Relative correlated motion of differentNucleon types1) with different spin orientation2) with different isospin orientation (proton liquid against neutron)

Deexcitation of single and double giant dipole resonance populated by coulomb excitation on 208Pb Energy 13 MeV and 26 MeV width is given by natural width described by Lorentz curve ndash studied by spectrometer TAPS at GSI Darmstadt (J Ritman Phys Rev Lett70(1993)533)

High energy transitions

Giant resonances are nicely populated by Coulomb excitation

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Production of neutral mesons during heavy ion collisions

π0 γ+γ (988 )η γ+γ (394 )

Decays

M2γγ = 2E1E2(1-cosΘ12)

Simulation of combinatorialbackground

Study of π0 and η meson production during heavy ioncollisions by means of spectrometer TAPS

Number of produced particles perone participant nucleon as dependency on collision energy (TAPS review)

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

Application of gamma spectrometry

1) Activation analysis -

A) Neutron ndash sample is irradiated by neutrons from reactor rarr production of radioactive nuclei rarr study of characteristic radiation

B) Fluorescence ndash sample is irradiated by X-rays rarr striking of electrons from atomic shell rarr characteristic X-rays

C) Determination of neutron flow from foil activation ndash similar to neutron activation analysis we know amount of irradiated material and we determine neutron flow ndash usage by reactor physics It is possible to use for determination of other particle beam flow Sensitivity limit is given by accuracy of gamma intensity determination ~ 1

known neutron flux rarr activity is proportional to amount of studied element

very sensitive ndash search of trace amounts of elementsSensitivity depends on element (range up to 8 orders) rarr up to pg (10-12g)

studied object is not damaged ndash possibility bdquoscanningldquo

Reactor LVR-15 of NRI

One of archeological artifacts studied at NPI ASCR

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

2) On ion beam

A) PIXE ndash (Particle Induced X-ray Emission) charged ions (mostly protons) with energy ~ 2 ndash 4 MeV rarr ionization of atoms rarr production of characteristic X-rays

Van de Graffův accelerator at NPI ASCR is used for material research using also PIGE and PIXE methods

Example of aerosol measurement at NPI ndash Department of neutron physics

Composition of samples for ecology archeology

Sensitivity up to 1 ppm (10-6)at μg material amount)

Principle of PIXE method

copy C2RMF T Calligaro Study of historical artifacts by PIXE and PIGE methods (C2RMF laboratory)

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator

3) X-ray diffraction crystallography

Determination of crystal structure biological objects and substances materials hellip by means of X-ray diffraction

Usage of synchrotron radiation

B) PIGE ndash Particle-Induced Gamma ray Emission) reactions of light nuclei with production of characteristic gamma rays

reactions (pγ) (ppacuteγ) and (pXγ)

Surface composition for material research

Method PIGE copy C2RMF T Calligaro Tandetrom at NPI ASCR is usedfor PIGE and PIXE studies

Also possibility of X-ray laserBased on free electrons

Synchrotron laboratory at GrenobleUndulator