The perspectives of nuclear astrophysics at fragmentation facilities

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The perspectives of nuclear astrophysics at
fragmentation facilities
Klaus Sümmerer, GSI Darmstadt

• 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

• Contributions from fragmentation-type facilities
• Spectroscopy of stopped fragments
• Unique storage-ring experiments
• Break-up reactions of unstable nuclei

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Nuclear-structure information from fragmentation
facilities

• 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 N126 r-process
  waiting-point nuclei and fissile nuclei below 238U

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Super-FRS low-energy branch
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Predicted production rates at Super-FRS
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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)

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Super-FRS Ring branch

• Mass and half life measurements
• Scattering and transfer ?Electron scattering

Short half lives, stochastic cooling
Long half lives, electron cooling, nuclear
reactions
H.Weick, H.Simon et al.
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Excitation of Giant Monopole Resonances to
determine the nuclear compressibility of
asymmetric nuclear matter

• GMR excitations in (?, ?) reactions
• measure near ?cm0 degree
• E? ? 1 MeV
• possible only in storage ring!
• wide range of A/Z
• E.g. 104-132Sn

E/A400 MeV, 1014 He atoms/cm2
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Reaction-rate measurements at fragmentation
facilities
Measure rad.capture reaction (p/n, ?) via
Coul.diss. (?,p/n)

• Advantages of inverse measurements
• Access to short-lived species
• Thick targets ? access to rare species
• Coincident detection of fast particles ? low
  background

• 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)