JPS57151882A - Neutron counting device for nuclear fusion reactor - Google Patents

Abstract

PURPOSE:To make it possible to count neutrons over the broad range of the dosage rate of the neutrons, by arranging a collimator whose opening degree is fixed so as to estimate the entire body of a plasma container, and providing at least two neutron detectors whose incident axes are intersected. CONSTITUTION:In a outer cabinet 1, an inner cabinet 7 comprising the same neutron decelerating material as that of the outer cabin is enclosed. Said inner cabinet 7 has a protruded part 4 which is intimately coupled into an opening 2 at the top surface of the outer cabinet, a longitudinal hole 5 which is opened in said protruded part, and a lateral hole 6 which crosses said longitudinal hole at a right angle. On the opening of the longitudinal hole, the collimator 8, which can look the entire body of the plasma container, and whose opening degree is fixed, is provided. The neutron detector 13 is embeded in the bottom of the longitudinal hole of the inner cabinet 7. The detector 15 is enclosed in the inner end of the lateral hole 6. In this neutron counting device, background counting can be decreased, and the neutrons over the wide range from the low dosage rate to the high dosage rate can be accurately measured.