| 摘要 |
PURPOSE:To obtain a transmission X-ray beam monitor which can monitor even a small diameter beam while utilizing the X-ray beam simultaneously with no influence on the the cross-sectional profile of the beam. CONSTITUTION:A monitor plate 2 is provided photoelectric membranes 4, 5, respectively, on the surface and the rear thereof, i.e., on the left and right when viewed from the incident direction of an X-ray beam 1. Secondary electron multipliers 6a, 6b are disposed oppositely to the photoelectric membranes 4, 5 on the surface and rear sides. When the X-ray beam 1 transmits the monitor plate 2, a faint electron current is emitted from the surface of the rear thereof toward the secondary electron multipliers 6a, 6b and amplified output currents therefrom are measured by means of electrometers 8a, 8b. Intensity and lateral displacement of the beam are then measured, respectively, based on the sum and difference of the measured current values.
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