| 摘要 |
PROBLEM TO BE SOLVED: To uniformize the sensitivity over a wide energy range in a portable neutron detecting device for detecting a neutron. SOLUTION: An opening 24 is formed on the human body side in a thermal neutron shield container 22, a thermal neutron scattered in a human body 20 passes through the opening 24, undergoes nuclear reaction in a thermal neutron reaction layer 28, and a charged particle produced is detected with a detector 32. A fast neutron passes through the thermal neutron shield container 22, undergoes nuclear reaction in a fast neutron reaction layer 26, and a recoil particle produced is detected with the detector 32. Epithermal neutrons and intermediate neutrons pass through the thermal neutron shield container 22, undergo nuclear reaction in an epithermal/intermediate neutron reaction layer 30 to generate charged particles. The charged particles generated by the intermediate neutrons are detected with the detector 32 without receiving attenuation by this material, and on the other hand the charged particles generated by the epithermal neutrons receive attenuation by self absorption effect during moving in a nuclear material, and only a part is detected by the detector 32. Sensitivity of the epithermal neutron can be controlled by the self absorption effect.
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