status and prospective of hirfl experiments on nuclear physics hushan xu institute of modern...

Status and Prospective of HIRFL Experiments on Nuclear Physics

Hushan Xu

Institute of Modern Physics, CAS, Lanzhou 73000

KITPC: Relativistic Many-body Problems for Heavy and Superheavy Nuclei Jun 8-Jun 27, 2009 Beijing

OUTLINEOUTLINE

• Introduction to HIRFL– Beam facilities

– Experiment sites

• Present Status & prospective of the equipments for nuclear physics experiment– SHANS: SHN, dripline neclei, atomic physics, …

– RIBLL1: spectroscopy and reaction of exotic nuclei, nuclear astrophysics, …

– CSRe: high precision mass and decay measurements, atomic physics with HCI, …

– ETF: RIB related physics, high density nuclear matter,…

• Summary & Future Development

Introduction to HIRFL: Beam facilities

N

CSRm

CSRe

SFC

SSC

SFC: 10 AMeV (H.I.), 17~35 MeV (p)

SSC: 100 AMeV (H.I.), 110 MeV (p)

CSRm: 1000 AMeV (H.I.), 2.8 GeV (p)

RIBLL1: RIBs at tens of AMeV

RIBLL2: RIBs at hundreds of A MeV

CSRe: storage ring with deceleration

RIB

LL

2

RIB

LL

1

Introduction to HIRFL: Exp. Sites

① Low energy site in general ② Atomic physics exp. site ③ SHANSSHANS - Spectrometer for Heavy Atom and Nuclear Structure

④ Heavy ion irradiation exp. site

⑤ RIBLL1RIBLL1 – 1st Radioactive Ion Beam Line in Lanzhou

10

⑥ ETFETF – External Target Facility at CSR ⑦ CSRe – Experimental Ring ⑧ PISA ⑨ Tumor therapy site

HPLUS

Present Status & Prospective of Present Status & Prospective of the Main Equipments for Nuclear the Main Equipments for Nuclear

Physics ExperimentPhysics Experiment

• SHANS: Spectrometer for Heavy Atom and Nuclear Structure

• RIBLL1: 1st Radioactive Ion Beam Line in Lanzhou

• CSRe: Experimental Ring of CSR

• ETF: External Target Facility at CSRm

SHANSSHANS

•ProductionProduction•A/Z selectionA/Z selection•Collection & coolingCollection & cooling ，， q=+q=+

11•Primary A selectionPrimary A selection•Z selectionZ selection，， q=+2q=+2•A selection (Z, A determineA selection (Z, A determine

d)d)•Decay measurement,…Decay measurement,…

RFQ 2

D1

D3

RFQ 2D2

Slit 1

Slit 2Q9,10,11

Laser

Q12,13,14

Q15,16

Q1,2,3

ReactionChamber

Target

Gas FilledSeparatorQ4

Q5,6

Q7,8

Detector

or Trap

RFQ 1

Spectrometer for Heavy Atom and Nuclear Structure

Gas-Filled Recoil Separator - GFRS

Configuration Qv-D-Qv-Qh

Trajectory length 6.5 m

Acceptance280mmmrad (h) 450mmmrad (v)

Central trajectory radius 1.8 m

Bending angle of D 52

Max. magnetic rigidity 2.88 Tm

Differe

ntial

Pumping Sys

tem

Reaction Chamber

Detection Chamber•Test by source•Testing with target recoils•To be tested with typical

reactions

RFQ Cooler and BuncherRFQ Cooler and Buncher

Under constru

ction

LaserLaser Multi-step Resonant IonizationMulti-step Resonant Ionization

•Gaol: SHE regionGaol: SHE region

No wave lenghth scanning neededNo wave lenghth scanning needed

Next at SHANS Next at SHANS

Step 1Step 1

• GFRS– Tested by the reaction(s) with known cross-section 09-10– Aiming at Z=110 region 10-11– Searching for the new isotopes at SHN region…

• RFQ– Tested with ion source 09-10– Combined with LMRI or/and GFRS…

• LMRI– Set up a system to produce 1+ ions 09-10– Systematic measurement of the 2nd ionization energy of the heavy atom: from k

nown to unknown & compared with theoretic calculation…

• LPT– Manufactory of the Lanzhou Penning Trap 09-10– Testing...

Step 2Step 2

Combining GFRS, RFQ, LMRI and LPT togetherPROBLEM:PROBLEM:

Beam Intensity

Future Plan for SHN at HIRFLFuture Plan for SHN at HIRFL

RIBLL 1RIBLL 1:: 1st Radioactive Beam Line in Lanzhou1st Radioactive Beam Line in Lanzhou

Nucl. Instr. Methods A 503 (2003)496

10 m

Q01Q02

D0

Q1Q2

D1 Q3Q4 Q5 Q6

D2

Q7Q8

Q9Q10

Q11Q12Q13 Q14 D4

Q15Q16

C2

T2

C1

T0

2B04D3

T1

9876543210

图2 RIBLL结构草图Equipped with

Clover det. for Clover det. for detection detection

Neutron Ball & WallNeutron Ball & Wall

Si-strip ArraySi-strip ArrayCsI(Tl) ArrayCsI(Tl) Array

Built in the end 1990s

• Total reaction cross-section• momentum distribution• Elastic scattering• -delayed neutron emision• p-p correlation function• Resonance states

Examples of the Results from Examples of the Results from RIBLL1RIBLL1

•Elastic scattering of weakly bound nuclei (IMP)

17F/17O angular dispersion plots

2ln( ) ( )d

d

Different slop reflects different component of the nuclear force starting to be effective

0 20 40 60 80 100 120 140 160 180 200

0

4

8

12

16

Coulomb Rainbow

( b1,1)

Veff Scatter

Coulomb Scatter17F+208PbE=141MeVV0=40.4MeV

a=0.62fmR0=9.35fm

b (f

m)

(deg)

Nuclear Rainbow

( b2,2)

0 100 200 300 400 5009

10

11

12

13

14

15

16

Ln

(d

d)

2

17F+208Pb

tu

2

Angular dispersion Classical deflection function

“turning angle” “nuclear rainbow angle”

Same angle

1/ 2

22 1

m

eff

r

Vbdr

r E

MMain conclusionsain conclusions

A possible way to extract the “nuclear rainbow angle” from experiment measurement.

The ratio of the “turning angle” over grazing angle could be a measure of the diffuseness of the surface of a nucleus

•β-delayed neutron spectra and spectra of 21N (PKU)

21N -delayed n-spectrum

2000 2500 3000 3500 40000

10

20

30

40

50

60

70

80

90

Co

un

ts

Energy(keV)

2780

2397

3175

4072

300 600 900 1200 1500 1800

0

100

200

300

400

500

600

Co

un

ts

Energy(keV)

280

351

511

1057

1218

1634

1674

21N -delayed n-spectrum -spectrum

68.8 AMeV 68.8 AMeV 2626Mg+Mg+99BeBe2121N (0.5 pps)N (0.5 pps)

MMain conclusionsain conclusions

Half-life of 21N: T1/2 = 82.91.9 ms

13 group of -delayed neutrons observed, total branch ratio is 88.74.2%

5 new levels of 21O assigned

New level scheme proposed for 21N and 21O

The experimental setup works even for the beam intensity at the level of 0.5 pps !

Part of the Planned Exps. in 09-10 Part of the Planned Exps. in 09-10

•Focusing on A< 40 region

Decay spectroscopy of Decay spectroscopy of 25,26,2725,26,27PP 66He knock-out He knock-out reactionreaction

Decay spectroscopy Decay spectroscopy of neutron-rich O, F, of neutron-rich O, F, Ne isotopesNe isotopes

CSReCSRe

• Status of CSRe– ToF detector for mass measurement as IMS ToF detector for mass measurement as IMS

(running)(running)– Schottky detctors for mass & decay measurement Schottky detctors for mass & decay measurement

(under testin(under testing)g)

– Electron cooler (under testing)– Cluster-jet target (under testing)

• Recent nuclear physics exps. at CSRe– Mass measurement: IMS, SMS, ToF– Decay measurement: SMS

Mass & Decay Measurement at CSRe: NOWMass & Decay Measurement at CSRe: NOW

•The end of 2007: test run•The end of 2008: 1st physics run

RIBLL2＋ CSRe

Isochronous mass spectrometer

36ArRIB

78KrRIB

Prelim

inary

78Kr Run78Kr Run

53Cog

53Com

53Feg

53Fem

Preliminary

A=2Z-1

Mass ExcessMass Excess

Nuclides MEIMP MEAME MEAME- MEIMP Setting

71Br -56602(133) -57060(570) -458(585) A=2Z-1

71Br -56618(137) -57060(570) -442(586) A=2Z+1

71Kr -45978(1470) -46920(650) -942(1607) A=2Z-1

71Kr -46470(327) -46920(650) -450(728) A=2Z+1

67Se -46966(512) -46490(200)# 476(550) A=2Z-1

65As -47418(567) -46980(300)# 438(641) A=2Z-1

63Ge -46677(263) -46910(200)# -233(330) A=2Z-1

Unit: keV

＃标记为理论预言值 ; 71Kr A=2Z+1设置下的值是通过 71Br质量值经衰变能导出的。

• New isomer states, new isotopes,…; checking the nuclear model

112Sn,124Xe beams

Mass & Decay Measurement at CSRe: NEXT Mass & Decay Measurement at CSRe: NEXT

09-10: try to accelerate Xe/Bi at CSR

78Kr beam

136Xe beam

Bi-U beams

• Bending energy, Shell structure, shape evaluation, …

• Origin of the element, nuclear synthesis, …

PLB,664(2008)162

ETF I: ETF I: External Target Facility, Phase IExternal Target Facility, Phase I

ETF II:ETF II: External Target Facility, Phase IIExternal Target Facility, Phase II

CsI+Clover 探测器

TPC

硅条探测器阵列CsI+Clover 探测器

TPC

硅条探测器阵列

New DetectorsNew Detectors• -ball (CsI(Tl) array + Clover)• TPC (at target region)• Si-strip array (behind TPC)• MWPC (inside dipole)

Possible PhysicsPossible Physics• For RIB Physics• For EoS of asymmetry nuclear matter• For high baryon density matter

To be constructed within 3 years

EoS of Asymmetry Nuclear MatterEoS of Asymmetry Nuclear Matter

0 )) (, (( ) sn ymp

nn

p pE E E

symmetry energy

B.A. Li, Nucl. Phys. A708, 365 (2002)

uncertainty

• Very limited experimental evidences to constrain the Esym at higher density

• Critical constrain to the radius of the neutron star

Can be done at ETF?Can be done at ETF?

18 18

12

12

12

B.A. Li, Nucl. Phys. A708, 365 (2002)

Density reachable at CSR energies

• n/p ratios, / ratios

• Nucleon differential flow

• Hard photons

• IMFs: isospin transport / diffusion / isoscaling

Possible observables

•Detector system: 2 years?•Proposals •Detailed simulation

Working package

PISAPISA

Shipped from FZJ to IMP in 2008Shipped from FZJ to IMP in 2008

Nucl. Instr. & Methods A 519 (2004)610-622• nn scattering cross section at CSR energies

• L-G phase transition of nuclear matter

• Spallation process:

measuring the spectra of LCP, extracting the excitation energy, and comparing with model calculations mainly focusing on the requirements from the applications

• Comparison of RAA & RpA at CSR energies

as a part of the energy scanning from RHIC energy down to CSR energy

Running as an external target Running as an external target exp. in the end of 2009.exp. in the end of 2009.

Summary & Future DevelopmentSummary & Future Development

Possible Exps.– SHN at GFRS within one year

– Mass measurement at CSRe started

– RIB Physics at RIBLL1 & ETF started & within one year

– Decay measurement at CSRe within one year?

– Density dependence of Easym at ETF two years later

– pA or AA at PISA within one year

Main Problem– Beam intensity

Future Development– Hadron Physics at GeV energies

Hadron Physics at GeV energiesHadron Physics at GeV energies

HPLUSHPLUS

HHadron adron PPhysics hysics LLananzhozhoUU SSpectrometerpectrometer

THANK YOUTHANK YOU

for your attentionfor your attention