Bochum 1998 – scientific programme
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HK: Hadronen und Kerne
HK 31: Nuclear Astrophysics II
HK 31.3: Talk
Tuesday, March 17, 1998, 14:30–14:45, G
P-nuclei production via the nuclear reactions 89Y(p,γ)90Zr and 93Nb(p,γ)94Mo 1.0mm♣ — •J.W. Hammer2, S. Harissopulos1, G. Souliotis1, K. Spyrou1, Ch. Chronidou1, T. Paradellis1, R. Kunz2, and A. Mayer2 — 1Inst. of Nuclear Physics, N.C.S.R. “Demokritos”, Gr-15310 Athens, Greece — 2Institut f"ur Strahlenphysik, Universit"at Stuttgart, D-70550 Stuttgart, Germany
An important aspect of astrophysical modelling is the reproduction of
abundances of the socalled p-nuclei. Various astrophysical calculations
have been so far successful in this task. In the A ≃ 90 mass region
however these calculations predict a severe underproduction for certain
p-nuclei. This discrepancy could be attributed to a lack of experimental
information concerning the cross sections of the involved (p,γ)
reactions. Hence, experimental data for a large number of radiative proton
capture reactions in the A ≃ 90 mass region are needed. As a
first step to this direction the cross sections of the nuclear reactions
89Y(p,γ)90Zr and 93Nb(p,γ)94Mo have
been measured at the Stuttgart Dynamitron accelerator with proton
beams of about 40 µA in the energy range 1.5–3 MeV. The angular
distributions of the γ-rays depopulating excited states of 90Zr
and 94Mo nuclei have been measured by 4 BGO-shielded HPGe detectors
of 100 % relative efficiency. Enriched targets on a gold backing
have been used. The results – important for a quantitative discussion of
the production of p-nuclei – are compared with statistical model
predictions.
1.0mm♣ Work supported
by NATO Collab. Research Grants Progr., Grant CRG 961086