<title>Novel technique for measurements of neutron cross sections and its application to nuclear astrophysics</title>

Abstract

ABSTRACT A new technique for measurements of total neutron cross sections is presented. This method has been applied to measurements of the excitation function for the + n system at E = 7.2 - 8.5 MeV, in order to obtain the 8Li(n , 1 B thermonuclear reaction rate. 1. INTRODUCTION In this work, we present a system for transmission measurements of total neutronaoss sectionsusing two silicon semiconductor detectors. One detector is placed in front of the target and monitors the incident neutron flux. The second detector is placed behind the target and measures the attenuation of the incident neutrons as well as their energy.This system has been used to measure the excitation function of the B(ri. x) reaction , where x is either a neutron or an alpha, and at incident neutron energies between 7.2 and 8.5 MeV.The parameters of the resonances observed in this reaction together with those observed in the previously measured B(n, a)8 Li reaction2 were used to derive the stellar rate for the 8L i(a, ri)1' B