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