| 摘要 |
PURPOSE:To detect the incident particle with high sensitivity by providing a secondary electron emission plate for emitting a secondary electron when the incident particle is emitted through one piece of incident port, and a constitution which can apply an electric field in the direction coinciding with the direction of a magnetic field. CONSTITUTION:An incident particle such as a neutral particle, a charged particle, etc., irradiates a secondary electron emission plate 1 through an incident port 0, and a secondary electron is generated. On the other hand, by applying a voltage between the secondary electron emission plate 1 and an acceleration electrode 2 from an acceleration power source 3, the secondary electron is accelerated in the direction of a line of magnetic force to irradiate a fluorescent screen 4 and light is generated, and this light is condensed by a condensing lens 5. Subsequently, this light is detected by a photodetector 7. In this case, in the acceleration electrode 2, since an electric field is applied in the direction coinciding with the direction of a magnetic field B, the electron is accelerated in a shape wound to the line of magnetic force, therefore, it does not occur that deterioration of sensitivity caused by a magnetic field is generated.
|
