Neutron decay of deep hole states and isobaric analog states in Sn-115 populated by the (He-3,alpha) reaction at 102 MeV

Neutron decay of excited hole states and isobaric analog states (IAS) popul ated by the Sn-116(He-3,alpha) reaction at an energy of 102 MeV has been in vestigated. The alpha -particles were analysed in a magnetic spectrograph p ositioned at 1.4 degrees and detected with a multiwire drift chamber. Excit ation energies in Sn-115 up to 23 MeV were studied. An array of neutron det ectors was positioned around the target at angles ranging from 68 degrees t o 209 degrees. The neutron data were analysed in terms of decay into final states, using statistical model calculations as a tool to extract lower lim its of nonstatistical decay. Nonstatistical decay was observed from states up to an excitation energy of about 18 MeV. The neutron emission of the IAS is compatible with 100% statistical decay. (C) 2001 Elsevier Science B.V. All rights reserved.