| 摘要 |
PURPOSE:To enable accurate measurement in wide range of energy region weighted appropriately by providing an ion chamber part having a pair of ion chamber loaded on a human body side and on outside of the human body, an electric source, a neutron filter and an arithmetic means. CONSTITUTION:A neutron equivalent dosimeter is loaded on a human body 26. If thermal neutrons 100 are irradiated from outside, these thermal neutrons 100 go into a second ion chamber 10-2 on the other side of the body and react here to produce alpha ray which causes ionization. Due to this ionization, electrons reach a collecting electrode and resulting pulse is counted by a counter. On the other hand, if medium and fast neutrons 200 are irradiated from outside and they go into the ion chamber 10-2, the medium and fast neutrons having high energy pass the ion chamber 10-2 due to very small reaction cross section area for 10B. Furthermore, the neutrons 200 pass through a neutron filter 14 and an ion chamber 10-2 as they are to go into the human body 26. The neutrons 200 having reached the human body 26 are scattered in the human body 26 to be thermal neutrons 300, go out of the human body and again go into the ion chamber 10-1.
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