MEASUREMENT OF (N,ALPHA) CROSS-SECTIONS FOR SHORT-LIVED PRODUCTS BY 13.4-14.9 MEV NEUTRONS

Twelve (n,alpha) activation cross-sections leading to short-lived nucl ei with half-lives between 37s and 15 min were measured in the energy range between 13.4 and 14.9 MeV by the activation method. The measured reactions involved the isotopes of Mg-26, Si-30, P-31, Cr-54, Cu-63, Ni-64, Ga-69, Ga-71, Rb-87, Y-89, Ru-104 and Cd-112 as the target. The intense 14 MeV neutron source facility (OKTAVIAN) at Osaka University was used for irradiation. The gamma-rays emitted from the irradiated samples were measured with high-purity germanium detectors. All cross- section values were obtained relative to the standard cross-section of the Al-27(n,alpha) Na-24 reaction. The cross-sections of three reacti ons were measured for the first time. The present experimental data we re discussed by comparing them with previously reported experimental d ata and the evaluated data of JENDL-3 and ENDF/B-VI. Six evaluated ite ms of data in JENDL-3 show reasonable agreement (within 7%), but the e valuation of the Mg-26(n,alpha) reaction is 25% higher than our data. Two items of evaluation data of ENDF/B-VI agree well, and one agrees w ithin 25%. (C) 1998 Elsevier Science Ltd. All rights reserved.