EXCITATION-FUNCTIONS OF NEUTRON THRESHOLD REACTIONS ON SOME ISOTOPES OF GERMANIUM, ARSENIC, AND SELENIUM IN THE 6.3-MEV TO 14.7-MEV ENERGY-RANGE

Cross sections were measured for the As-75(n,p)Ge-75, As-75(n,alpha)Ga-72, As-75(n,2n)AS-74, Se-74,Se-76,Se-78(n,p)As-74,As-76,As-78, S-78,As-80(n, alpha)Ge-75,Ge-77, Ge-72,Ge-73,Ge-74(n,p)Ga-72,Ga-73,Ga-74, and Ge-70,Ge-76(n,2n)Ge-69,Ge-75 reactions over the 6.3- to 14.7-MeV neutron energy range. Samples of As2O3, selenium, and germanium or GeO2 of natural isotopic abundance were used. The neutrons were produced via the D(d, n)3 He reaction using a deuterium gas target at a variable energy cyclotron (E(n) = 6.3 to 11.9 MeV) and via the T(d,n)He-4 reaction using a solid titanium-tritium target at a neutron generator (E(n) = 14.7 MeV). The activation technique was used in combination with high-resolution gamma-ray spectroscopy. The experimental excitation functions are well reproduced by the nuclear model calculations, based on statistical multistep reaction theory.