Experiments

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• Nuclear astrophysics studies at the FRS-ESR: ground state and decay properties of neutron-rich nuclei in the 132Sn region.

  A key element in the search for the r-process site are properties of very neutron-rich nuclei far from stability [] - specifically masses, ß-decay half-lives, neutron capture rates and probabilities for ßdelayed neutron emission.
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  However, for most of the nuclei along or near the r-process path no experimental information is available, and nuclear physics input for r-process calculations is derived from theoretical models []. This lack of reliable nuclear data for neutron-rich nuclei is especially problematic for nuclei around 132Sn, which are involved in the synthesis of the isotopes in the A=130 peak of the solar r-process abundance distribution.
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  We plan to measure the probabilities for ß-delayed neutron emission and the ß-decay half-lives of 16 nuclei in the Cd - Xe region.

  Download proposal (1998)

• In the study of beta decay in highly charged ions.

  ß decay plays an important role at various stages of the stellar evolution and in many nucleosynthesis processes []. We propose to study the ß-decay (ß^-, bound ß^-, ß⁺, EC) to evaluate the strength parameters as well as the charge state dependence of the branching ratios in the case of bare H-like, He-like and Li-like ions while measuring the nuclear lifetimes.

  Download proposal (2000)

• ESR measurements of proton-induced reaction rates in the Gamow window of the astrophysical p process

  For a substantial improvement of the yet uncertain reaction rates [for the p-process] we propose a program for the measurement of (p,g) and (a,g) cross sections in the ESR.
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  We propose to demonstrate the experimental technique for (p,g) measurements in the ESR with a test beam time using stable 112Sn and 124Sn ions.
  
  This project is now continued by the PIANO group.

  Download (2004)

• Electron screening and α-decay.

  One of the open questions in nuclear astrophysics is the interpretation of the electron screening effects observed in low-energy nuclear reactions with light nuclei []. As pointed out by several authors [] screening corrections deeply affect the reaction rates at low relative energies.
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  We propose to measure Qα-values and &alpaha;-decay lifetimes of fully stripped heavy ions in order to get for the first time an unambiguous determination of the electron screening energy. This is possible because changes in Q-value and lifetime are expected, with respect to the neutral atoms, due to the screening effect on the nucleus. In fact relative changes in the decay constant δλ/λ have been calculated by some authors to range from 20% up to 100%, depending on the Qα- value involved in the decay. We stress that at present no lifetime measurements of bare and fewelectron alpha-emitters are available and the experimental facility FRS-ESR at GSI represents a worldwide unique opportunity to perform the proposed studies.

  Download proposal (2006)

• Astrophysical reaction rates studied by coulomb dissociation of radioactive beams.

  Since 7Be(p,g)8B is of utmost importance for solar-neutrino physics and since it is an ideal test case for the method of C.D., we propose to perform further measurements of the 8B C.D. and to improve on our previous experiment [].
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  Of special current interest is the nucleosynthesis in the neighbourhood of long lived radioactive isotopes which have been (or probably will be) observed with g-ray observatories (COMPTEL, INTEGRAL). Two of these nuclei are 22Na and 26Al, where the decay of the latter has already been observed. [] At present, a decision on the stellar site(s) of 22Na and 26Al production cannot be made due to the lack of the necessary nuclear physics data. [] This proposal aims at a measurement of the resonant proton-capture on 22Mg and 26Si. Sizable reaction rates on these nuclei may lead to a bypass of the reaction flow around the long-lived readioactive daughter isotopes, thus having a strong impact on the observable [] abundancies.

  More information about this experiment Download proposal (1998)

• Two-proton decay of 19Mg.

  Download proposal (2002)

Proposals

• ß-decay of very neutron-rich Rh, Pd, Ag nuclei including the r-process waiting point 128Pd.

  Measurement of ß-decay half-lives and Pn values for the very neutron-rich Rh-Pd-Ag isotopes. While the half-lives of 125-128Pd and 122-125Rh will be measured for the first time, the statistical uncertainty of the known 121Rh and 124Pd half-lives will be greatly reduced. All the proposed Pn values are currently unknown.

  Download proposal (2006)

• The dipole response of proton-rich nuclei -- pygmy and giant resonances in 32Ar and 34Ar.

  Download proposal (2006)

• Study of the Big-Bang nucleosynthesis reaction D(a,g)6Li by Coulomb Dissociation of 6Li.

  Recently a new compilation of charged-particle induced thermonuclear reaction rates has been published, providing upper and lower limits for 80 reaction rates. Following this nuclear physics analysis, the impact of these uncertainties on Big Bang nucleosynthsis has been studied. The most dramatic effect is observed for D(a,g)6Li which induces uncertainties of a factor of ≈20 on the 6Li yield. To reduce this uncertainty and to be able to estimate the feasibility of observation of primordial 6Li abundancies in very old stars, new measurements of the D(a,g)6Li reaction are required.

  Download proposal (2000)