BACKWARD ANGLE N-P DIFFERENTIAL CROSS-SECTION AT 96 MEV

An accurate measurement of the n-p differential cross section, in the angular range 116-degrees-180-degrees, at 96 MeV is reported. Between 150-degrees and 180-degrees the angular distribution is steeper than earlier measurements and potential predictions. The sensitivity of the differential cross section to isospin-singlet, J less-than-or-equal-to 4 phase-shift parameters was studied, and it was found that the observed difference at the most backward angles is sensitive mainly to L greater-than-or-equal-to 3 phase shifts

The Be-9(n,p)Li-9 reaction and the Gamow-Teller unit cross section

Double differential cross sections of the Be-9(n,p)Li-9 reaction have been measured at 96 MeV in the angular range 0 degrees-27 degrees up to about 20 MeV excitation energy. In addition, the C-12(n,p)B-12 reaction has been measured in the same angular and excitation energy range. Cross sections fdr reactions leading to the ground state and the first excited state (2.69 MeV) of Li-9 have been analysed using peak-fitting techniques. The data have been compared with cross sections obtained from distorted-wave Born approximation calculations. A Gamow-Teller (GT) unit cross section for the ground state transition of 7.4 +/- 1.2 mb/sr was determined From the identified GT strength. Discrepancies in the Gamow-Teller unit cross sections for different (n,p) and (p,n) transitions from the Be-9 ground state, resembling the situation for C-13, have been found. (C) 2000 Elsevier Science B.V. All rights reserved

Measurements of neutron-induced fission cross-sections of Tl-205, Pb-204,Pb-206,Pb-207,Pb-208 and Bi-209 with a multi-section Frisch-gridded ionization chamber

Neutron-induced fission cross-sections of Tl-205, Pb-204,Pb-206,Pb-207,Pb-208 and Bi-209 have been measured in the energy range from 30 to 180 MeV. The measurements were performed with quasi-monoenergetic neutron beams using a multi-section Frisch-gridded ionization chamber. The neutron-induced fission cross-sections of U-238 were used as reference data. The experimental techniques are described in detail as well as the data processing. The results are compared with existing experimental data. (c) 2006 Elsevier B.V. All rights reserved

THE FE-54,FE-56)(N, P) MN-54,MN-56 REACTIONS AT E(N)=97 MEV

Double-differential cross sections of the Fe-54,Fe-56(n, p) reactions have been measured at 97 MeV in the angular range 0-30-degrees for excitation energies up to 40 MeV. The spectra have been decomposed into different multipolarities by a technique based on the use of sample angular distributions calculated within the distorted-wave Born approximation. From the identified Gamow-Teller strength, S(beta)+ values were obtained for Fe-54 Fe and Fe-56. Comparisons with available shell-model calculations of the GT strength were made. The results are important for models of supernova explosions since electron-capture rates, which are proportional to S(beta)+, in 1f2p-shell nuclei affect the dynamics of the star. At higher excitation energies, the spectra are dominated by L = 1 strength in broad distributions with a maximum at about 12 MeV. Microscopic calculations based on the random-phase approximation were performed and compared with the experimental data