| 摘要 |
PURPOSE:To provide a long life ion sensing device, which ensures that a high sensitivity is obtained with a low operating voltage and which provides controllability for the operating voltage in compliance with the gain of a secondary electron multiplier. CONSTITUTION:Negative ion are cast incident to and makes bombardment of a conversion dinode 22 on which a positive voltage is impressed from a slit 21 and are converted into positive ions in the amount proportional to the bombardment. The obtained positive ions are attracted to a secondary electron multiplier 23 with a neg. voltage impressed on the cathode 24 and are boosted. The boosted electrons are accelerated by a metal film 26 with a voltage impressed and run against a scintillator 27. These electrons are converted into light and sensed by a photo-multiplier tube 28.
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