Prompt fission neutron investigation in ²³⁵U(n_th,f) and ²⁵²Cf(sf) reactions

The prompt neutron emission in thermal neutron induced fission of ²³⁵U and in the spontaneous fission of ²⁵²Cf was investigated by using digital signal electronics. The goal was to check a new revised data analysis software with fission fragment (FF) kinetic energy corrections after prompt fission neutron (PFN) emission. The revised software was used to reanalyze old data measured in ECJRC-IRMM, where ²⁵²Cf(sf) reaction was investigated. Both measurements were done using similar twin Frisch grid ionization chamber for fission fragment detection with equivalent NE213 fast neutron detector. About 0.5*10⁶ FF with PFN coincidences have been analyzed in both measurements. The fission fragment kinetic energy, mass and angular distribution were investigated along with prompt neutron time of flight and pulse shape analysis using a six channel synchronous waveform digitizer (WFD) with sampling frequency of 250 MHz and 12 bit resolution in the ²³⁵U(n_th,f) reaction. Similar WFD with sampling frequency of 100 MHz was used for PFN investigation in ²⁵²Cf(sf) reaction. These two experiments were considered as a reference for further investigations with a new setup composed of position sensitive ionization chamber to detect FF and an array of 32 liquid scintillators recently constructed in Dubna to detect neutrons. (authors)