A Study of the Elastic Scattering of 2-3 Mev Neutrons in Sulphur and Calcium

Abstract

In the present work an associated particle time-of-flight spectrometer has been designed and used to study the elastic scattering of neutrons with energies of 2.99 Mev and 2.18 Mev. The 2H(d,n)3 He reaction was used as the source of neutrons. The time of origin of the neutron was determined by detecting the associated helium particle. Problems related to detecting the He particles and resolving them from a large number of other charged particles produced at the same time, have been overcome by using thin deuterated polyethylene targets. For the production of neutrons with an energy of 2.18 Mev the neutron yield was monitored by counting the associated FHe particles. Due to the incomplete resolution of the 3He particles the neutron yield at an energy of 2.99 Mev was determined by monitoring the proton yield from the competing 2H(d,p)3H reaction. Differential elastic scattering cross-sections were measured for calcium and sulphur at neutron energies of 2.99 Mev and 2.18 Mev respectively. Measurements were limited to scattering angles up to 80° for calcium and 100° for sulphur. The measurements obtained for calcium were compared with the results of Reber and Brandenburger at an energy of 3.29 Mev and with the results of Abramson et al at a neutron energy of 2.83 Mev. The results obtained for sulphur were comparable with the measurements of Holmqvist and Wiedling for a neutron energy of 2.47 Mev. The elastic scattering angular distributions were analysed using the optical model computer code RAROMP. In addition an associated particle time-of-flight system was investigated for the 2H(d,n)3 He reaction at the lower incident deuteron energy of 130 Kev which is more generally available.