A multi-layered fast ionization chamber prototype for fission cross section measurements

Aiming at measuring the fission cross sections of various actinides in a wide neutron energy range at the newly built China Spallation Neutron Source (CSNS)- White Neutron Source (WNS), a dedicated multi-layered fast fission ionization chamber prototype was constructed. The physical design of the prototype and the front-end electronics which are optimized to the features of CSNS are here described. The performance of the prototype with uranium targets at a D-T neutron source is presented, focusing in particular on the good ability in fission fragment discrimination, high detection efficiency of 95.5% and time resolution of 20.3 ns.