Development of 252Cf fast fission chamber

The waveform and amplitude spectra of output signals from the Model 142B preamplifier connected to a 252Cf fission chamber have been measured. The fission chamber is filled with methane, argon, or their mixture. The distance between the two parallel-plate electrodes of the chamber ranges from 1 mm to 5 mm, and the voltage from 50 V to 700 V D.C. The neutron strength from 252Cf fission chamber is about 2.07 x 104 neutron/s. In favorable circumstances, the rise time of pulse signals from the preamplifier reaches 7.69 (1 +- 9.1%) ns, the detection efficiency of fission fragments reaches, 98.4%, and pulse signals caused by 252Cf fissions are distinguished clearly from those caused by 252Cf alpha decays