nuclear physics input to astrophysics: e.g. nuclear structure: masses, decay half lives, level...

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)