| 摘要 |
PURPOSE:To secure a device removing scattering electrons in a primary electron beam, one of noise components which cause the S/N ratio to drop off, and improving the degree of sensitivity ever so better, by installing such a device that mechanically interrupts the primary electron beam, in position between an electron gun and a charged particle detector. CONSTITUTION:A primary electron beam 2 is interrupted by a rotary plate 16 whereby this primary electron beam 2 is irradiated on a sample 3 after passing through plural detectors 9 and an electrode inside 29 only when it runs past a hole of the rotary plate 16. An Auger electron 10 produced out of a primary electron irradiation point 30 describes an analyzed electron orbit 31 and passes through a space between an inner cylindrical electrode 5 and an outer cylindrical electrode 4, reaching to plural charged particle detectors 9 after passing through a slit system 15. At this time, only when the primary electron beam 2 is colliding with the rotary plate 16, an electric current flows into an ammeter 24, turning an interspace between terminals 26 and 27 to ON, and a signal securable in a lock-in amplifier 33 is outputted to an X-Y recorder 34. A spectrum being secured like this is exempted from a drop in the S/N ration produced out of the disturbance of signals due to scattering electrons by the slit 15 or the like in the primary electron beam, thus coming into a state of high sensitivity. |
