nuclear physics input to astrophysics: e.g. nuclear structure: masses, decay half lives, level...
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Nuclear physics input to astrophysics: e.g. Nuclear structure: Masses, decay half lives, level properties, GT strengths, shell closures etc. Reaction rates for capture reactions Isospin and density dependence of the nuclear equation of state
Klaus Sümmerer, GSI Darmstadt
The perspectives of nuclear astrophysics at fragmentation facilities
Contributions from fragmentation-type facilities:1. Spectroscopy of stopped fragments2. Unique storage-ring experiments3. Break-up reactions of unstable nuclei
1. Experiments with stopped fragments:
Combines production/separation at high energy with experiments at low energy
High energy thick degrader high isotopic purity Complementary to ISOL: Access to refractory elements not available from ISOL Access to very short half lives
Future (GSI/RIA): Access to N=126 r-process waiting-point nuclei and fissile nuclei below 238U
Nuclear-structure information from fragmentation facilities
Super-FRS: low-
energy branch
Predicted production rates at Super-FRS
Storage-ring experiments
Mass/half life measurements at storage rings: Mass measurements over large areas of the nuclear chart Resolution of isomers Access to very short half lives (TOF method) Half life measurements for ionized species (e.g. BBD)
Scattering and transfer reactions at internal target: (p,n) to measure GT strengths (, ’) to measure giant monopole resonance (EOS of asymmetric nuclear matter)
Super-FRS: Ring branc
h
Short half lives,
stochasticcooling
Long half lives,
electroncooling,nuclear
reactions
H.Weick, H.Simon et al.
Mass and half life measurements Scattering and transfer Electron scattering
GMR excitations in (, ’) reactions: measure near cm=0 degree E 1 MeV possible only in storage ring! wide range of A/Z E.g. 104-132Sn
Excitation of Giant Monopole Resonances to determine the nuclear compressibility of asymmetric nuclear matter
0 2 4 6 8
c.m . (degree)
100
102
104
106
CO
UN
TS
pe
r D
AY
134Sn
132Sn
104Sn
G aint M onopole R esonance
G iant M onopole Excita tion in Snexpected spectra
SnSnSn
132
104
134
E/A=400 MeV, 1014 He atoms/cm2
Advantages of inverse measurements: Access to short-lived species Thick targets access to rare species Coincident detection of fast particles low background
Reaction-rate measurements at fragmentation facilities
Disadvantages of inverse measurements: Connects only ground states Different sensitivity to multipolarities Small Q-values
Recent examples: 7Be(p,)8B (GSI) 8B(p,)9C (RIKEN) 14C(n,)15C (GSI)
Measure rad.capture reaction (p/n, ) via Coul.diss. (,p/n)