METHOD FOR DETERMINING THE AVERAGE CHARGE OF A PULSE NEUTRON FLUX IN A FISSION CHAMBER

摘要

The proposed method for determining the average charge of a pulse neutron flux in a fission chamber consists in connecting the chamber with an electrode and fission material to an external power-supply source, irradiating the chamber by neutrons, measuring the neutron-induced current (in) and the number of pulses (Nd) within a specified time interval (?t) or the pulse rate (nd) at discrimination levels (Ud) that are varied within a specified interval in which the absolute slope of the characteristic representing the dependence of the Nd or nd parameter on the Ud parameter is maximal. At least one measurement is accomplished at the discrimination level that corresponds to the minimal slope ofthe said characteristic. The measurement results are approximated by a reverse exponential function depending on the squared argument and are used for determining the average charge (Q) of the pulse neutron flux. The proposed method provides the possibility to measure the average charge with an error of 3 ... 9 %, depending on the number of measurement, and data reliability of no less than 95 %.