| 摘要 |
PURPOSE:To reduce the energy loss of a particle beam so that the measurement can be executed precisely by adhering a collector electrode to a resin plate by vapor-depositing a metal or performing the plating. CONSTITUTION:When the particle beam 12 passes through the inside of a housing filled with a gaseous material 3, the particle beam 12 and a molecule of the gaseous material 3 are brought into collision with each other and a gas molecule is ionized. Also, when an electric field is applied between a high voltage electrode 4 and a collector electrode 20 formed in a resin plate by vapor- depositing a metal by using a high voltage power source 7 an ionized electron e<-> and an ion i<+> are collected to the collector electrode 20 and the high voltage electrode 4, respectively. The number of ionized electrons e<-> and ions i<+> is proportional to the intensity of the passing particle beam, and the moving speed of the electron e<-> is higher than the moving speed of the ion i<+>, therefore, the electron e<-> is collected to the collector electrode 20 and measured by a measuring circuit. That is, the irradiation quantity of the particle beam 12 is measured by a dose measuring electrode 26, and the gradation of the particle beam 12 when the particle beam 12 is spread out and distributed can be measured by a flatness measuring electrode 27.
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