公开(公告)号：JPH0434828A

公开(公告)日：1992-02-05

申请号：JP14179190

申请日：1990-05-30

Applicant: ALOKA CO LTD

Inventor： SATO HIROO ,  YAMAMOTO YUKIYOSHI ,  SAKUMA YOICHI

IPC: G01T3/00 ,  H01J47/12

Abstract: PURPOSE:To obtain a simple detector detecting a high-density neutron beam in real time without the effect of a gamma-ray by detecting a neutron beam and a gamma-ray in a first ionization chamber and concurrently detecting the gamma-ray in a second ionization chamber with specific gas sealed in each of the said chambers, and eliminating the participation of the gamma-ray, based on each output of the first and second ionization chambers, to detect a neutron. CONSTITUTION:Output by a neutron and a gamma-ray is obtained in the neutron detection ionization chamber 26 of a first ionization chamber which is injected with the BF3 gas of a first gas including a neutron-reactive atom and generating ionization by the incidence of the neutron and the gamma-ray, and output by only the gamma-ray is gained in the gamma- ray detection ionization chamber 28 of a second ionization chamber which is injected with the BF3 gas of a second gas including an atom, which is the isotope of the neutron-reactive atom and nonsensitivity to the neutron, and producing the ionization by the incidence of the gamma-ray and not producing the ionization by the incidence of the neutron. Then participation of the gamma-ray relating to neutron detection is eliminated and the output by only the neutron is obtained, by determining the sum of the outputs of the ionization chambers 26 and 28 when the applied voltage of them has reversed polarity, or by having the difference between the outputs of the ionization chambers 26 and 28 when first applied voltage has the same polarity, and thus a simple gamma-ray compensated neutron detector which can correctly detect the neutron is obtained.