| 摘要 |
PURPOSE:To make it possible to measure both 1-cm dose equivalent and 3-mm dose equivalent efficiently with a single apparatus by providing a first incident window for transmitting a low energy region excellently and an adjusting window which can be freely attached to and removed from the first incident window. CONSTITUTION:A first incident window 29 and an adjusting window 30 are provided at a first detecting part 10. For example, a voltage of -500V is applied to an applying electrode 18 of the first detecting part 10. At this time, when, e.g. +20V is applied to a first capacitance correcting electrode 32, the effective volume of the ionization chamber of the first detecting part 10 can be reduced by about 4 - 5%. Thus, the total detecting sensitivity can be lowered by a specified level. Meanwhile, a voltage of +500V is applied to an applying electrode 20 of a second detecting part 12. At this time, when, e.g. -20V is applied to a second capacitance correcting electrode 34, the effective volume of the ionization chamber of the second detecting part 12 can be reduced by 4% or more. Thus the radiation of a characteristic curve 202 can be measured.
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