Nuclear Astrophysics at IMP Xiaodong Tang
Institute of Modern Physics Chinese Academy of Sciences
The r-Process Nucleosynthesis: Connecting FRIB with the Cosmos, May 31 - June 17, 2016
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OUTLINE • Jinping Underground lab for
Nuclear Astrophysics (JUNA) • Research with Heavy Ion
Research Facility at Lanzhou (HIRFL)
• Research with High Intensity Accelerator Facility (HIAF)
• Beijing ISOL @ CIAE
Jinping Underground lab for Nuclear Astrophysics(JUNA)
Highly sensitive detector
Excellent background
First deep underground accelerator driven by ECR
Great People
CIAE,IMP,TSU,SJTU,SDU, SCU 2018: first experiment
0 1 23 4
5 6
7 8
9 10
111213
14
1516
17181920
2122
2324
25262728
2930
3132
33343536
3738394041
424344
45464748
49505152
535455
56
5758
59
H (1)He (2)Li (3)
Be (4) B (5) C (6) N (7)
O (8) F (9)
Ne (10)Na (11)
Mg (12)Al (13)Si (14) P (15)
S (16)Cl (17)
Ar (18) K (19)
Ca (20)Sc (21)
Ti (22) V (23)
Cr (24)Mn (25)
Fe (26)Co (27)
Ni (28)Cu (29)
Zn (30)Ga (31)
Ge (32)As (33)
Se (34)Br (35)Kr (36)Rb (37)
Sr (38) Y (39)
Zr (40)Nb (41)
Mo (42)Tc (43)
Ru (44)Rh (45)Pd (46)Ag (47)
Cd (48)In (49)
Sn (50)Sb (51)
Te (52) I (53)
Xe (54)
HCNO breakout
Mass
Weak rate
Mass, reaction rate and weak rate
Nuclear Processes on the surface of neutron star
rp-process
HCNO breakout
EC
neutrons
protons
Mass known Half-life known nothing known
Neutron star (Chandra) Weak rate
KS 1731-260
p process
Supernova (Chandra,HST,..)
E0102-72.3 AGB s-process 95Zr(n,γ)96Zr
abun
danc
e
solar r abundance observed
Z
CS22892-052
40 50 60 70 80 90-2
-1
0
1
Massive star 12C+12C
np-process 84Sr
Big Bang AGB 14C(,γ)18O
Origin of element
Neutron capture
Masses,reaction rates,weak rates
Modified based on Schatz’s slide
CSRe
CSRm 1000 AMeV (H.I.), 2.8 GeV (p)
RIBLL1 RIBs at tens of AMeV
RIBLL2 RIBs at hundreds of AMeV
Heavy Ion Research Facility at Lanzhou
Nuclear Astrophysics at HIRFL
CSRe
CSRm 1000 AMeV (H.I.), 2.8 GeV (p)
RIBLL1 RIBs at tens of AMeV
RIBLL2 RIBs at hundreds of AMeV
热CNO突破反应测量:次级束流线
高精度质量测量:冷却储存环
直接测量:低能核天体物理终端
Nuclear Astrophysics at HIRFL
电荷改变截面测量:外靶终端
Heavy Ion Research Facility at Lanzhou
1. B. Mei et al., NIM A 624, 109 (2010) 2. X. L. Tu et al., PRL 106, 112501 (2011) 3. X. L. Tu et al., NIM A 654, 213 (2011) 4. Y. H. Zhang et al., PRL 109, 102501 (2012) 5. X. L. Yan et al. Astrophys. J. Lett. 766, L8 (2013) 6. H. S. Xu et al., IJMS 349, 162 (2013) 7. X. L. Tu et al., J. Phys. G41, 025104 (2014) 8. W. Zhang et al., NIM A 756, 1 (2014) 9. B. Mei et al., Phys. Rev. C 89, 054612 (2014) 10. P. Shuai et al., Phys. Lett. B 735,327 (2014)
Beams: 56Ni, 78Kr, 86Kr, 112Sn
Precision 10-6~10-7
(20-200 keV)
Mass measurement at HIRFL
Improving Precision (27)
First Measurement (26)
64Ge was considered to be a waiting point
Sp(65As) >-250 keV (AME2003) The waiting points determine:
• Reaction flows • Burst duration • Final abundance
65As
Waiting point does not wait
Sp(65As) = -90 (85) keV
89%–90% of reaction flow passes 65As, 64Ge is not an important waiting point
New mass measurement finds that 64Ge is not a waiting point
time (s)
AME2003 (dashed) This work (solid)
~30 s
Waiting point does not wait
X.L. Tu et al., PRL106(11):112501
New experimental initiatives
RIBLL1 Ext. Target
Cooler Storage Ring
HCNO break out: Active Target
TPC
Reaction
HCNO breakout: Int. Target
Reaction
Weak rate: Charge
Exchange
Weakrate
rp、np: Double TOF
IMS
Mass
6 million USD awarded this morning!
How were the heavy elements from iron to uranium made?
铁
金 铀
• mass • stellar half life • Decay branching • Fission • n capture xsec
Superconducting Linac: Length: 180 m Energy: 17 MeV/u (U34+) CW and pulse modes
Booster Ring: Circumference: 471 m Rigidity: 34 Tm Beam accumulation Beam cooling Beam acceleration
Spectrometer Ring: Circumference:188.7 m Rigidity: 13T m Electron cooling Stochastic cooling In-ring experiment
High Intensity Accelerator Facility
Ions Energy Intensity
SECR 238U34+ 14 keV/u 0.05 pmA
iLinac 238U34+ 17 MeV/u 0.028 pmA
BRing 238U34+ 0.8 GeV/u ~1.41011 ppp
Main beam parameters
Unprecedented beam Intensity ( Comparison with HIRFL): - Primary beam intensity increases by 1000 – 10000 times
- Secondary beam intensity increases by ~10000 times
Precisely-tailored beams: - Beam cooling (electron, stochastic, laser; high quality, very small spot )
- Beam compression (Ultra-short bunch length: 150ns)
- Long period slow extraction (Super long, high energy, quasi-continuous beam)
Facility Competence
Production of RNB at higher energy
Neutron Number
Prot
on N
umbe
r Nuclides Available at HIAF
One of the world’s most powerful facilities to search for new isotopes
Boundary of Known Nuclei
Prolific sources of nuclides far away from the stability line will be provided using projectile fragmentation, in-flight fission, multi-nucleon transfer, and fusion reactions. The limits shown are the production rate of one nuclide per day, which enable the “discovery experiments”.
Particle/day
A=175
A=153
A/Z=2.6
A/Z=2.9
Charge state distribution complicates mass measurement
A Z Q IonName Mtoq[u/e] dm[keV] T[1/2][atomic] 155 58 58 ^{155}Ce^{58+} 2.670983 400# 200# ms 155 59 58 ^{155}Pr^{58+} 2.670843 17 1# s 163 61 61 ^{163}Pm^{61+} 2.670826 503# 200# ms
¾ 3 similar A/Q,Only 155Pr mass is known by now Contribution by X.L. Yan
Measurement of Pxn with Ring
A(Z,N) B(Z-1,N-X)
Xn
Heavy recoil detector
Neutron wall A(Z,N) C(Z-1,N)
Schottky detector
Forward neutron: Neutron wall Heavy decay product: charged particle detector/Shottky
Conventional Beta+neutron correlation is limited by the poor response to low energy neutron.
Internal target experiment z Boost beam current (108 particles,106 HzÆ max
effective intensity : 1014 pps) z Free of beam induced background z Ultra-thin target (1013 atoms/cm2)
Conventional target: 10 mg/cm2 Carbon foil Æ >1017 atoms/cm2
¾ Allow low energy particle escaping from the target
¾ Minimize beam particle energy loss in target
ITE Si array in UHV (EXL)
A case study 132Sn (T1/2=40 s)
z HIAF: 3.5E6 ppsÆstored ion: 2.2E8 particles Effective intensity: 2.2E14 pps z RIBF: 3E6 pps z FRIB: 1E8 – 1E9 pps z EURISOL: 4E11 pps z BEIJING ISOL(CARIF): 5E10 pps
Light ion induced direct reactions elastic scattering (p,p), (,), … nuclear matter distribution (r), skins, halo structures inelastic scattering (p,p’), (,’), … giant resonances, deformation parameters, B(E2) values, transition densities charge exchange reactions (p,n), (3He,t), (d, 2He), … Gamow-Teller strength transfer reactions (p,d), (p,t), (p, 3He), (d,p), … single particle structure, spectroscopic factors spectroscopy beyond the driplines neutron pair correlations nuclear structure relevant to nuclear reactions at stellar energy (ANC, energy, spin, Jp, decay branching ratio) knock-out reactions (p,2p), (p,pn), (p,p 4He)… ground state configurations, nucleon momentum distributions, cluster correlations Modified based on Egelhof’s talk
Production of n-rich isotopes at low energies
Fission products of 238U
Products of MNT reactions
Products of fusion reactions
The low-energy intense beams will enable producing very n-deficient nuclei by fusion reactions and particularly heavy and super-heavy n-rich nuclei by multi-nucleon transfer reactions.
z Synthesize new isotopes. z Measure the g.s. properties. z Build the decay schemes. zBuild a bridge to the island of SHN. z Simulate the rp and r processes. z Study the evolution of shell structure.
A/Z=2.7
A/Z=3.0
Production of Neutron Rich isotopes using MNT
Watanabe et al., PRL 115, 172503 (2015)
KISS project @ RIKEN N126 factory @ ANL GaLS@DUBNA T-Rex@TAMU...
MNT
Fragmentation
Properties of Super Heavy Nuclides
Island ?
¾Produce new elements and isotopes. ¾Gain insight into the mechanisms of fusion. ¾Measure masses and lifetimes.
¾Perform chemistry with the heaviest elements. ¾Hunt for new K-isomers. ¾Obtain information on the single particle states.
V. I. Zagrebaev et al. PRC 87, 034608 (2013)
Is there a limit, in terms of proton and mass numbers, to the existence of nuclei? Unprecedented opportunities for the synthesis of new isotopes and structure studies.
54Cr + 243Am 119* 55Mn + 243Am 120* 58Fe + 243Am 121*
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Endpoint of the r-process
r-process ended by n-induced fission
(Z,A)
(Z,A+1)
(Z,A)
(Z+1,A)
(Z,A+1)
n-capture (DC) fission
b- fission fission
fission barrier
n-induced fission b-delayed fission spontaneous fission
or spontaneous fission
(different paths for different conditions)
(Goriely & Clerbaux A&A 348 (1999), 798
• Mass • Decay
Good and easy fragments
91Kr 1.8 s
132Sn 39.7 s
Good and easy: Large yield Long half live Easy to separate
CARR
78Ni beam by 91Kr from reactor
With 7X1010pps 91Kr: 78Ni 103-4pps RIBF: 101pps
I. Tanihata, NIM B266(2008)4067
Summary • Chinese Nuclear Astrophysics community is
growing rapidly with strong support from government
• Need better interaction with JINA
• Need something like JINA to bring observation, modeling, nuclear experiment together and make better scientific contribution