nuclear astrophysical reactions by unstable beams and progress of brif and brifii...
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Nuclear astrophysical reactions by unstable beams and
Progress of BRIF and BRIFII不稳定核束核天体物理反应北京放射性核束装置的进展
Wei-ping Liu 柳卫平[email protected]
China Institute of Atomic Energy, CIAE 中国原子能科学研究院6th China Japan Joint Nuclear Physics Symposium
第六届中日核物理会议May 16-20, 2006Shanghai 上海
Study of some key nuclear astrophysical reactions by
unstable nuclear beams
Interplay between astrophysics and nuclear physics• Nuclear process
– Main energy of star to balance gravitational collapse– Mechanism of isotope synthesis apart from Hydrogen– Rule the evolution process from the first few minutes after big
bang to just before the end of star life• Nuclear astrophysics
– Using nuclear physics to explain the energy production and element synthesis in star and cosmos
Exp The
Nucl. Data
Astro. Obs.
Astro. Model
Exp The
Abundance Dist.
Nuclear astrophysics and physics of unstable nuclei
• primordial and super novae high temperature and density environment, large amount of unstable nuclear involved into nuclear burning
RIKEN RIBF proposal
Nuclear astrophysics ‘Lab’
B. Pfeiffer, et al., Z. Physik A357, 253 (1997)
Reaction network
lkjijklAlkj
ilkj
kjijkAkj
ikjjj
j
ij
i
YYYVNN
YYVNNYNdt
dY
,22
,,,,
,,
,
Cross section
Decay half-life
Challenge to experiment
0.2 0.25 0.3 0.35 0.4 0.45 0.5T9
100
150
200
250
300
350
yg
re
nE
ni
Ve
k
T9 vs. Gamow window
11C(p,)12N
•Gamow window•Extremely low energy•Vanishing low cross section
Our solution: indirect method
RIB production
W.P. Liu, NIM B204(2003)62
(d,n) or (d,p) measurement
ANC or Spec factorAstrophysical reaction rates
W.P. Liu, PRL77(1996)611
Direct capture process of 11C(p,)
N. C. Shu,…, W. P. Liu et al., Nucl. Phys. A 758 (2005) 419c
• Key reaction in hot pp chain• Dominated by direct capture
W. P. Liu et al., NPA728(2003)275
First measurement of primordial 8Li(n,)9Li reaction rate
• Destroy reaction of 8Li: 8Li(n,)9Li, 8Li(d,p)9Li in inhomogeneous big bang， APJ429(1994)499
• Half-life of 8Li: 0.83 s， direct (n,) exp. impossible
Z. H. Li, W.P. Liu et al.， PRC 71, 052801(R) (2005)
Comment on our results
• The paper presents excellent experimental work and removes a longstanding debate about the absolute cross section of 8Li(n,)
• As far as I know, so far, no results have been published to determine a neutron capture rate of astrophysical importance
13N(d,n)14O 13N(p,)14O
20 40 60 80 10010-2
10-1
100
101
102
Experimental data DWBA1 DWBA2 DWBA3 DWBA4 DWBA5 DWBA6
d/
d
(mb
/sr)
c.m.
(deg)
PRC, submitted
Summary of reaction studied
9C
12N
18Ne
17F
14O
Opportunities from BRIF and BRIF II
BRIF: Beijing Radioactive Ion Facility
Physics : why BRIF
Intensity 1-109, energy 100 keV-10 MeV/u, RIA proposal
The current Tandem lab
• Beam type, only stable, no noble gas
• Energy range, less than 14 MeV/q• Instrumentation, no RMS, no ISOL• Beam time: 100 % overdue
BRIF
100 MeV 200 A compact proton cyclotron20000 mass resolution ISOL, 2 MeV/q super-conducting LINAC
BRIF energy and mass resolution
BRIF research opportunities and combinations
100 MeV, 200AProton Cyclotron
ISOLMass Resolution20000
RIB
Stable Beam
Ion Source
SuperConductingLINAC
TandemAccelerator15 MV
Neutron dataRadiation physics
Decay dataMaterial physics
Nuclear dataRadiation physicsNuclear structureReactionAstrophysicsAtomic PhysicsApplications
Radiation physicsNuclear structureReactionAstrophysicsAtomic Physics
• Tandem with unstable beam, proton-rich, fission
• heavy ion beam with higher beam energy, 20 MeV/q
• 100 MeV proton and neutron beams• available by the year 2010
• 100 MeV neutron
• ISOL• current
terminals• limitation of
instrument and machine time
More n-rich beam: CARRISOL
• Horizontal tube
• He-jet + ISOL• Neutron flux
1X1014 /cm2/s• Available in
2007
Nuclide ISOL (pps)
I-135 3×106
Xe-138 9×107
Cs-138 9×107
Xe-140 1.7×108
Cs-140 2.2×108
Cs-142 2.7×108
Low RFQ for new injector17 MeV/q super-conducting LINACRMSLarge acceptance spectrometerDecay measurements
Beam energy
串列实验室束流能量
0. 1
1
10
100
0 50 100 150 200 250 300
质量数
(MeV
/u)
单核
子能
量
13 MV 单核子能量15 MV 单核子能量超导加速段单核子能量超导加速器单核子能量库仑位垒
RFQ/DTL
Low energy normal temp RFQ+ finger type DTL, multi charge heavy ion beam up to the energy accepted by SC LINAC
36MHz
SC LINAC
•Energy gain 17 MeV/q•36 ¼ wave length QWR•9 100 L LHe tank
QWR
LHe tank
Large acceptance
spectrometer
•Large D Q + detectors•Mass range 100-200， energy 5-10 MeV/u•Solid angle 80 mSr， P acceptance 10％•Mass resolution 300 via TOF and tracking
RMS
Mass resolution 400，solid angle 16 mSr, horizontal and vertical angular width 3.6 degree，acceptation angle 0-10 degree。Main parameters。 Name Magnets Deflector Radius, meter 1 5 Bending angle, degree 40 20 Gap, cm 12 12.5 Maximum Field 1.0 Tm 25 MV
Dipole
Targetchamber
ElectroDeflector Detector
chamber
Quadruples
Beamdiagnostics
Beamdiagnostics
12 m
ElectroDeflector
Quadruples
Gamma array
•10X BGO+seg. HPGe• Eff. 10 % @ 1 MeV•resolution 6 keV
100 1000 10000
0.00
0.04
0.08
0.12
0.16
0.20
0.24
0.28
0.32 (c) 10 Clover (4x60x90mm) +10 normal HPGe
Eff
icie
ncy
E(keV)
(d) GAMMASPHERE
(b)4 Clover(4x60x90mm)+10 normal HPGe
(a) 15 normal HPGe
Normal HPGe (70x70mm)
Cou
nts
v/c=0FWHM=2.1keV
v/c=0.02 FWHM=4.0keV
Clover (4x70x100mm)
v/c=0
FWHM=2.1keV
v/c=0.02
FWHM=14keV
Clover (4x70x100mm)
E/keV
Cou
nts
v/c=0 FWHM=2.1keV
v/c=0.02 FWHM=14keV
Doppler corrected FWHM=10keV
Clover (4x70x100mm)
E/keV
v/c=0 FWHM=2.1keV
v/c=0.02Doppler correctedFWHM=10keV
Segmented(4x4)Doppler correctedFWHM=5.8keV
Research opportunities
• Systematic study of shell evolution
• Nuclear astrophysics
• Mechanism of SHE
• Properties of medium mass neutron rich nuclei
• New decay modes
•Gamma array
•Recoil mass separator
•Large acceptance spectrometer
•Decay setup
Conclusion• BRIF and BRIFII will open up exciting research opportunities• With BRIFII:
– new experimental terminals– higher beam energy of 35 MeV/q– 100 % more beam time by separate operation– Limit: overall instrumentation usage– Available by the year of 2013
• Chances are still open, and we welcome contributions, suggestions and new proposals
• We would like to collaborate with major domestic and foreign research groups and world labs to take their full research potential and to do cooperative jobs
• Call for user communities to build machine and detector and physics task force with more flexible way
• A nice play ground in Beijing to connect locations