A study of ( 3He, n) reactions on 24Mg, 28Si and 32S

Abstract

Using a time-of-flight spectrometer, measurements have been made on the neutron groups from the 24Mg( 3He, n) 26Si reaction at 4.9, 5.2 and 5.6 MeV, the 28Si( 3He, n) 30S reaction at 5.14 and 5.6 MeV and the 32S( 3He, n) 34Ar reaction at 5.6 MeV. The ground state Q-values for the reactions were measured to be 75±30, −579±25 and −760±30 keV, respectively, Groups were measured corresponding to levels at 2.78, 3.35, (3.77), 3.89 and 4.16, all ±0.04 MeV in 26Si, 2.21, 3.43 and 3.71, all ±0.03 MeV and at 2.19±0.04 and 3.59±0.06 MeV in 34Ar. There is a close correspondence between some of the new levels reported here and analogous states in the A = 26, 30 and 34 isobaric triplets. Angular distributions and absolute cross sections have been measured for several neutron groups from these reactions. The results show that the reaction is predominantly a direct one at these energies. Plane wave and distorted wave double stripping calculations give reasonable fits in the forward direction particularly for L = 0 transitions. Simple double stripping theory does not explain the relatively large cross sections at backward angles observed for some transitions.