Delayed neutrons and high-energy γ-rays from decay of 87Br

Abstract

Delayed neutrons and high-energy γ-rays following decay of 87Br have been studied to characterize the β-decay to and the decay of neutron unbound levels in 87Kr. The principal part of the neutron spectrum appears due to some 20–30 individual transitions and for seven of these, decay by γ-ray emission has been demonstrated. The β-strength function derived from these data and the decay scheme at lower energies is dominated by a broad resonance located near the neutron binding energy which can be identified with the main strength of a single-particle transition. The fluctuations in the reduced β-transition probabilities are found to be in accord with the Porter-Thomas distribution and the observed level density just above the neutron binding energy is consistent with the Gilbert and Cameron prediction after accounting for fluctuation in the β-decay transition probabilities.