The 90Zr(n,p)90Y reaction at En = 98 MeV

Double-differential cross sections of the 90Zr(n,p) reaction have been measured at 98 MeV in the angular range 00-300 for excitation energies up to 40 MeV. The spectra have been interpreted in terms of direct and multistep reactions. The contributions from the latter have been calculated using a statistical theory of multistep direct reactions. The direct parts of the spectra have been decomposed into their different multipole components by using peak-fitting and multipole-decomposition techniques, based in sample angular distributions calculated within the distorted-wave Born approximation. An extensive microscopic calculation based on the random-phase approximation has also been performed and the results are compared with the experimental data. A value Sβ+ = 1.7 ± 0.2 is extrated for the Gamow-Teller strength, suggesting an occupancy ν2 = 0.09 ± 0.01 for the 1g9/2 proton orbital. This value has been compared with recent results from (d, 3He) proton pickup and (e, e'p) knockout reactions. (orig.)