lifetime measurements after multi-nucleon transfer ...lea-colliga/public-docs/2009... · energy...
TRANSCRIPT
Lifetime measurements after multi-nucleon transferreactions at VAMOS and LISE in GANIL
J. Ljungvall (CEA IRFU/SPhN→GANIL→CSNSM)for the E553 (and E551) collaboration(s)
Lea Colloqia, Paris, 23-24 Nov. 2009
Scientific motivation(s)
Physics around Z=28, N=40
E553: Neutron-rich irons 62,64Fe - Z=26, N=34-38
f7/2 protons removed
Adding f5/2 neutrons
→ 1g9/2 ↓ 1f5/2 ↑→ Collectivity builds up
→ N=40 “quenched”
Recent work explains low 2+1 energies in 64Fe in pf restricted model
(N. Hoteling et al. PRC 74, 064313 (2006))... Some B(E2)’s willsort it out→Lifetimes
+ Shell Model AND Beyond Mean Field
Lea Colloqia, Paris, 23-24 Nov. 2009
Scientific motivation(s)
Physics around Z=28, N=40
E553: Neutron-rich irons 62,64Fe - Z=26, N=34-38
f7/2 protons removed
Adding f5/2 neutrons
→ 1g9/2 ↓ 1f5/2 ↑→ Collectivity builds up
→ N=40 “quenched”
Recent work explains low 2+1 energies in 64Fe in pf restricted model
(N. Hoteling et al. PRC 74, 064313 (2006))... Some B(E2)’s willsort it out→Lifetimes
+ Shell Model AND Beyond Mean Field
Lea Colloqia, Paris, 23-24 Nov. 2009
Scientific motivation(s)
Physics around Z=28, N=40
E553: Neutron-rich irons 62,64Fe - Z=26, N=34-38
f7/2 protons removed
Adding f5/2 neutrons
→ 1g9/2 ↓ 1f5/2 ↑→ Collectivity builds up
→ N=40 “quenched”
Recent work explains low 2+1 energies in 64Fe in pf restricted model
(N. Hoteling et al. PRC 74, 064313 (2006))... Some B(E2)’s willsort it out→Lifetimes
+ Shell Model AND Beyond Mean Field
Lea Colloqia, Paris, 23-24 Nov. 2009
Scientific motivation(s)
Physics around Z=28, N=40
E551: Reduction of the Z=28 gap - the other side of the coin
g9/2 neutrons added
→ 1πf5/2 ↓ 1πf7/2 ↑Z=28 reduced (...)
Lea Colloqia, Paris, 23-24 Nov. 2009
Scientific motivation(s)
Measure lifetimes of excited states in neutron-richnuclei using Recoil Distance Doppler Shift
Why (now)?
Complements Coulomb excitation measurements
RIB facilities coming up: Technical development
How?
1 Multi-nucleon transfer
2 Spectrometer
3 A Plunger+γ-ray spectrometer
E553:238U [email protected] MeV/A on 64Ni target
Lea Colloqia, Paris, 23-24 Nov. 2009
Scientific motivation(s)
Measure lifetimes of excited states in neutron-richnuclei using Recoil Distance Doppler Shift
Why (now)?
Complements Coulomb excitation measurements
RIB facilities coming up: Technical development
How?
1 Multi-nucleon transfer
2 Spectrometer
3 A Plunger+γ-ray spectrometer
E553:238U [email protected] MeV/A on 64Ni target
Lea Colloqia, Paris, 23-24 Nov. 2009
Scientific motivation(s)
Measure lifetimes of excited states in neutron-richnuclei using Recoil Distance Doppler Shift
Why (now)?
Complements Coulomb excitation measurements
RIB facilities coming up: Technical development
How?
1 Multi-nucleon transfer
2 Spectrometer
3 A Plunger+γ-ray spectrometer
E553:238U [email protected] MeV/A on 64Ni target
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Experimental setup
VAMOS+EXOGAM+Plunger
Beam
Target
Degrader
VAMOS
EXOGAM
VAMOS gives
Identifcation
Velocity
Excitation energy
]° [Lab
Theta36 38 40 42 44 46 48 50 52 54
Kin
etic
en
erg
y [M
eV/A
]
4
4.5
5
5.5
6
6.5
7
7.5
8 Ex = 0 MeV
Ex = 20 MeV
Ex = 40 MeV
The real thing
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Experimental setup
VAMOS+EXOGAM+Plunger
Beam
Target
Degrader
VAMOS
EXOGAM
Energy [keV]845 850 855 860 865 870 875 880 885 890
Co
un
ts/k
eV
0
20
40
60
80
100
120
]° [Lab
Theta36 38 40 42 44 46 48 50 52 54
Kin
etic
en
erg
y [M
eV/A
]
4
4.5
5
5.5
6
6.5
7
7.5
8 Ex = 0 MeV
Ex = 20 MeV
Ex = 40 MeV
The real thing
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Experimental setup
VAMOS+EXOGAM+Plunger
Beam
Target
Degrader
VAMOS
EXOGAM
Energy [keV]845 850 855 860 865 870 875 880 885 890
Co
un
ts/k
eV
0
20
40
60
80
100
120
]° [Lab
Theta36 38 40 42 44 46 48 50 52 54
Kin
etic
en
erg
y [M
eV/A
]
4
4.5
5
5.5
6
6.5
7
7.5
8 Ex = 0 MeV
Ex = 20 MeV
Ex = 40 MeV
The real thing
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Experimental setup
VAMOS+EXOGAM+Plunger
Beam
Target
Degrader
VAMOS
EXOGAM
Energy [keV]845 850 855 860 865 870 875 880 885 890
Co
un
ts/k
eV
0
20
40
60
80
100
120
]° [Lab
Theta36 38 40 42 44 46 48 50 52 54
Kin
etic
en
erg
y [M
eV/A
]
4
4.5
5
5.5
6
6.5
7
7.5
8 Ex = 0 MeV
Ex = 20 MeV
Ex = 40 MeV
The real thing
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Experimental setup
VAMOS+EXOGAM+Plunger
Beam
Target
Degrader
VAMOS
EXOGAM
Energy [keV]845 850 855 860 865 870 875 880 885 890
Co
un
ts/k
eV
0
20
40
60
80
100
120
The real thing
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Analysing the data
The gamma rays
60Fe
800 900 1000 1100 1200 13000
20
40
60
80
100
800 900 1000 1100 1200 13000
20
40
60
80
100
800 900 1000 1100 1200 13000
20
40
60
80
100
62Fe
850 900 950 1000 1050 1100 1150 1200 1250 13000
20
40
60
80
100
120
850 900 950 1000 1050 1100 1150 1200 1250 13000
20
40
60
80
100
120
850 900 950 1000 1050 1100 1150 1200 1250 13000
20
40
60
80
100
120
64Fe
700 750 800 850 900 950 10000
5
10
15
20
25
700 750 800 850 900 950 10000
5
10
15
20
25
700 750 800 850 900 950 10000
5
10
15
20
25
40 µm
250 µm
750 µm
Energy [keV]
2+ →0+
4+ →2+
2+ →0+
4+ →2+
2+ →0+
4+ →2+
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Analysing the data
Decay curves
Normalisation
1 Intensity in 2+1 →0+
1
2 Number of ionsidentified in VAMOS
Consistent results from thetwo
Decay cruves 62,64Fe
50
100
150
200
250
300
350
400
450
500
0 100 200 300 400 500 600 700 800
Co
un
ts in
pe
ak
Distance [µm]
Iuij
62Fe 2
+->0
+
Iuij
62Fe 4
+->2
+
0
20
40
60
80
100
120
140
160
180
0 100 200 300 400 500 600 700 800
Co
un
ts in
pe
ak
Distance [µm]
Iuij
64Fe 2
+->0
+
Iuij
64Fe 4
+->2
+
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Analysing the data
“...all the things you told me just to tell me later thatyou told me so...”
Questions analysing RDDS data after multinucleon transfer reactions
1 Angular distribution
The same for 2+1 and 4+
1 ?Reorientation effect?
2 Side feeding
What feeds the 2+1 states?
Problems from low statistics → No γγ. No experience to estimatethese effects, unlike after fusion-evaporation.
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Analysing the data
“...all the things you told me just to tell me later thatyou told me so...”
Questions analysing RDDS data after multinucleon transfer reactions
1 Angular distribution
The same for 2+1 and 4+
1 ?Reorientation effect?
2 Side feeding
What feeds the 2+1 states?
Problems from low statistics → No γγ. No experience to estimatethese effects, unlike after fusion-evaporation.
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Results
Some new lifetimes
A τ (ps) Eex (keV) B(E2; ↓) (e2fm4)This exp. NNDC exp. exp.
60 11(1) 12(2) 823.6 190(20)62 7.4(9) - 876.8 214(26)
64 7.4(26) - 746.4 470+210−110
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Conclusions
Physics
Strong increase ofcollectivity
Systematics ok
We need pfgd space
0
100
200
300
400
500
600
700
52 54 56 58 60 62 64 66 68
B(E
2;2
+->
0+)
[e2fm
4]
Mass
From this experiment
From previous experiments
E. Caurier et al. SM pf
E. Caurier et al. SM pfgd
Girod et. al CGM(GOA)
500
600
700
800
900
1000
1100
1200
1300
1400
1500
52 54 56 58 60 62 64 66 68
E 2
+1 [
ke
V]
Mass
ExperimentE. Caurier et al. SM pf
E. Caurier et al. SM pfgdGirod et. al CGM(GOA)
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Conclusions
Physics
Strong increase ofcollectivity
Systematics ok
We need pfgd space
0
0,1
0,2
0,3
0,4
B(E
2; 0
1+→
2 1+)
(e
2 b2 )
FeNiZnGeSe
26 28 30 32 34 36 38 40 42 44 46 48 50 52N
500
1000
1500
2000
E(2
+)
(k
eV)
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Conclusions
Physics
Strong increase ofcollectivity
Systematics ok
We need pfgd space
0
100
200
300
400
500
600
700
52 54 56 58 60 62 64 66 68
B(E
2;2
+->
0+)
[e2fm
4]
Mass
From this experiment
From previous experiments
E. Caurier et al. SM pf
E. Caurier et al. SM pfgd
Girod et. al CGM(GOA)
500
600
700
800
900
1000
1100
1200
1300
1400
1500
52 54 56 58 60 62 64 66 68
E 2
+1 [
ke
V]
Mass
ExperimentE. Caurier et al. SM pf
E. Caurier et al. SM pfgdGirod et. al CGM(GOA)
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Conclusions
Experimental technique
Works well!
Idenfication in VAMOS ok
Sufficient statistics in -2p+2n channel
No problems with elastic scattering of beam/target/degrader
What about 4+1 states?
In “our” irons τ4+1≈ 1ps↔35µm: Degrader distances chosen for the
2+1 states...
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Conclusions
Experimental technique
Works well!
Idenfication in VAMOS ok
Sufficient statistics in -2p+2n channel
No problems with elastic scattering of beam/target/degrader
What about 4+1 states?
In “our” irons τ4+1≈ 1ps↔35µm: Degrader distances chosen for the
2+1 states...
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Conclusions
“...come flooding back to me now.”The Magnetic Fields
...but what about our difficulties?
Angular distribution - seems ok...
Reorientation - seems ok...
Feeding - seems ok...
We need γγ to be sure. Missing factor 10 in statistics
Lea Colloqia, Paris, 23-24 Nov. 2009
E553: Conclusions
“...come flooding back to me now.”The Magnetic Fields
...but what about our difficulties?
Angular distribution - seems ok...
Reorientation - seems ok...
Feeding - seems ok...
We need γγ to be sure. Missing factor 10 in statistics
Lea Colloqia, Paris, 23-24 Nov. 2009
E551: Experiment
Experimental setup - LISE+EXOGAM+Plunger
Primary beam 76Ge 61 MeV/A
Secondary beam 74Zn
Secondary target CD2 34mg/cm2, degrader Be 54mg/cm2
Goal: 74Zn(d,3He)73Cu
Figures courtesy of Baptiste Mouginot IPN Orsay
No 73Cu seen. Studentin need of data - 74Zn
Lea Colloqia, Paris, 23-24 Nov. 2009
E551: Experiment
Experimental setup - LISE+EXOGAM+Plunger
Primary beam 76Ge 61 MeV/A
Secondary beam 74Zn
Secondary target CD2 34mg/cm2, degrader Be 54mg/cm2
Goal: 74Zn(d,3He)73Cu
Figures courtesy of Baptiste Mouginot IPN Orsay
No 73Cu seen. Studentin need of data - 74Zn
Lea Colloqia, Paris, 23-24 Nov. 2009
E551: Online analysis
Some online spectra
0 mm
2.5 mm
3.5 mm
5 mm
2 cm
2+1 in 74Zn populated via
inelastic scattering
Excitation also on degrader
The student gets to work forhis degree!!!
Figures courtesy of Baptiste Mouginot IPN OrsayLea Colloqia, Paris, 23-24 Nov. 2009
L’avenir
Next year
Reduced Transition probabilities in 68,70,72Ni by Recoil-Doppler-ShiftMethod
Spokespersons E. Clement, J.Ljungvall, and, I. Celikovic
70Ni B(E2,4+1→2+
1 ) and higher
Complex states - test of shell-modelB(E2,4+
1→2+1 )/B(E2,2+
1→0+1 ) allows IBM approach
72Ni B(E2,2+1→0+
1 )
Polarisation 68Ni coreorbital ordering - tensor force νg9/2-πf7/2/πf5/2
A VAMOS+EXOGAM+Plunger experiment!!!
Lea Colloqia, Paris, 23-24 Nov. 2009
L’avenir
Next year
Reduced Transition probabilities in 68,70,72Ni by Recoil-Doppler-ShiftMethod
Spokespersons E. Clement, J.Ljungvall, and, I. Celikovic
70Ni B(E2,4+1→2+
1 ) and higher
Complex states - test of shell-modelB(E2,4+
1→2+1 )/B(E2,2+
1→0+1 ) allows IBM approach
72Ni B(E2,2+1→0+
1 )
Polarisation 68Ni coreorbital ordering - tensor force νg9/2-πf7/2/πf5/2
A VAMOS+EXOGAM+Plunger experiment!!!
Lea Colloqia, Paris, 23-24 Nov. 2009
L’avenir
AGATA on tour
(some of the) Physics we will try todo
Weakening of N=50, Z=28shells...
Nuclear shapes neutron richA≈100
Lea Colloqia, Paris, 23-24 Nov. 2009
L’avenir
AGATA on tour
(some of the) Physics we will try todo
Weakening of N=50, Z=28shells...
Nuclear shapes neutron richA≈100
Tool we will use
High-intensity radioactivebeams
AGATA (EXOGAM2)
PRISMA/VAMOS (LISE)
RDDS
Lea Colloqia, Paris, 23-24 Nov. 2009
L’avenir
AGATA on tour
AGATA vs. EXOGAM
Beam
Target
Degrader
Focusing element
Bρ separation
M,Z determination
γ-ray
detec
tors
EXOGAMVAMOS -ray energy [keV]γ
600 700 800 900 1000 1100 1200
γ-γ
0
20
40
60
80
100
120
140
160
180
Lea Colloqia, Paris, 23-24 Nov. 2009
L’avenir
AGATA on tour
AGATA vs. EXOGAM
Beam
Target
Degrader
Focusing element
Bρ separation
M,Z determination
γ-ray
detec
tors
AGATA dem.VAMOS -ray energy [keV]γ
600 700 800 900 1000 1100 1200
γ-γ
0
20
40
60
80
100
120
140
160
180
pxEntries 1339650Mean 769.6RMS 500.4
200 400 600 800 1000 1200 1400 1600 1800 20000
200
400
600
800
1000
1200
1400
pxEntries 1339650Mean 769.6RMS 500.4
gg g4pEntries 15802Mean 762.3RMS 497.6
Total projection
50*(Gate on 4+->2+)
Lea Colloqia, Paris, 23-24 Nov. 2009
Ending titles
Declarations of dependance
Presented by J. Ljungvall but made possible by theE553 and E551
collaborations
Lea Colloqia, Paris, 23-24 Nov. 2009
Extras
“...come flooding back to me now.”The Magnetic Fields
...but what about our difficulties?
Angular distribution - seems ok...
Reorientation - seems ok...
Feeding - seems ok...
We need γγ to be sure. Missing factor 10 in statistics
Lea Colloqia, Paris, 23-24 Nov. 2009
Extras
“...come flooding back to me now.”The Magnetic Fields
...but what about our difficulties?
Angular distribution - seems ok...
Reorientation - seems ok...
Feeding - seems ok...
]°Phi [-150 -100 -50 0 50 100 150
]°T
het
a [
0
20
40
60
80
100
120
140
160
180 bkg subtractedRaw Number of counts at angle for 2+,
bkg subtractedRaw Number of counts at angle for 4+,
We need γγ to be sure. Missing factor 10 in statistics
Lea Colloqia, Paris, 23-24 Nov. 2009
Extras
“...come flooding back to me now.”The Magnetic Fields
...but what about our difficulties?
Angular distribution - seems ok...
Reorientation - seems ok...
Feeding - seems ok...
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 100 200 300 400 500 600 700 800
Is 2+/Is 4+
Distance [µm]
60Fe
Is2+/Is4+ θ=135-150
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
0 100 200 300 400 500 600 700 800
Is 2+/Is 4+
Distance [µm]
60Fe
Is2+/Is4+ θ=135-150Is2+/Is4+ θ=160-180
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
0 100 200 300 400 500 600 700 800
Is 2+/Is 4+
Distance [µm]
60Fe
Is2+/Is4+ θ=135-150Is2+/Is4+ θ=160-180
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
0 100 200 300 400 500 600 700 800
Is 142/
Is 170
Distance [µm]
60Fe
2+
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
0 100 200 300 400 500 600 700 800
Is 142/
Is 170
Distance [µm]
60Fe
2+
4+
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
0 100 200 300 400 500 600 700 800
Is 142/
Is 170
Distance [µm]
60Fe
2+
4+
We need γγ to be sure. Missing factor 10 in statistics
Lea Colloqia, Paris, 23-24 Nov. 2009
Extras
“...come flooding back to me now.”The Magnetic Fields
...but what about our difficulties?
Angular distribution - seems ok...
Reorientation - seems ok...
Feeding - seems ok...
]°LAB Angle [36 38 40 42 44 46 48 50 52
Kin
etic
En
erg
y [M
eV/A
]
3.5
4
4.5
5
5.5
6
6.5
7
7.5
EnergyIncreasing Exictation
We need γγ to be sure. Missing factor 10 in statistics
Lea Colloqia, Paris, 23-24 Nov. 2009
Extras
“...come flooding back to me now.”The Magnetic Fields
...but what about our difficulties?
Angular distribution - seems ok...
Reorientation - seems ok...
Feeding - seems ok...
We need γγ to be sure. Missing factor 10 in statistics
Lea Colloqia, Paris, 23-24 Nov. 2009