Multiparameter study of ¹H, ³H and ⁴He in fast neutron induced fission of ²³⁵U

Abstract

The emission probabilities per fission of α-particles, tritons and protons have been measured in fast neutron induced fission of ²³⁵U. The measurements were carried out at neutron energies of 120, 180, 230 and 550 keV. AΔE-E semiconductor detector telescope was used to identify different light charged particles and the fission fragments were detected with an ionization chamber. The three-parameter data corresponding to the pulse heights from the ΔE-E detectors and the ion-chamber were recorded event by event on magnetic tape and were analyzed off-line by computer. No significant variation in the most probable energy (E̅) and the standard deviation (σ_E) of the energy spectra of different light charged particles with incident neutron energy was observed, although E̅_α was seen to have a slightly higher value beyond E_n=230 keV. The yield of α-particles in fission induced by neutrons of E_n ~200 keV was found to be higher by about 20 % than that in thermal neutron induced fission. The yields of tritons and protons were found to increase significantly with neutron energy.