Fission fragment velocity distribution measurement using time of flight technique

Abstract

Two large area position sensitive Multi Wire Proportional Counters (MWPCs) have been developed for the detection of Fission Fragments (FFs). The detectors were characterized using FFs from 252Cf source to obtain position information by employing delay-line read out method and the resolution is about 1 mm in both X and Y directions. Velocity distribution of the FFs produced from spontaneous fission of 252Cf has been measured employing a time-of-flight (TOF) technique, using a barium fluoride (BaF2) detector and a MWPC. The most probable velocities obtained for the heavy and light fragment groups are 1.035 ± 0.003 and 1.378 ± 0.004 cm/ns, respectively. The energy dependence of fragment velocity distribution was also studied after degrading the energy of the fragments by using Mylar foils. It is observed that the width of the distribution for the heavy fission fragments decreases with the reduction in the energies, but for light fragments it does not show any significant dependence on the energy.