Development of a position-sensitive thermal neutron monitor

摘要

A position-sensitive monitor for the detection of thermal neutrons with a flux density of up to I = 108 neutrons/(cm~2 s) is developed in order to implement beam control at experimental facilities of the PIK reactor complex. The monitor is designed in such a way that the beam transmission coefficient does not fall below 95%. This design is based on a multiwire proportional chamber with cathode data readout with the use of an LC delay line. Two mixtures are chosen to be used as the working gas: 3He/CF4 for beams with a density of up to 106 neutrons/(cm~2 s) and N_2/CF4 for I >106 neutrons/(cm~2 s). It is demonstrated that the computer modeling data agree well with the results of studies of the parameters of the 3He/CF4 working mixture with a thermal neutron beam. The developed detector may serve as the basis for the construction of monitors that are planned to be installed at experimental facilities of the PIK reactor at the Petersburg Nuclear Physics Institute.