| 摘要 |
PURPOSE:To realize an optimum design and improve the resolution without resticting the form of a pole piece for an object lens, by forming a gaseous layer on the electron beam optical axis, and radiating the electron beams to the gaseous layer. CONSTITUTION:On the way that electron beams 3 pass through an intermediate chamber 8, the electron beams strike to the accumulated gas molecules g in the intermediate chamber 8, giving the speed V1 in the direction of the electron beam passing to the gas molecules g. When the initial speed of the gas molecules g is V0, the given speed V=V0+V1. Furthermore, since the electrons which passed through a differential exhaust throttle 7 and the gas molecules repeat striking again and again to accelerate the speed of the gas molecules g, almost all the gas molecules g are converted into neutral particle beams 3' and radiated over the sample 5. The neutral particles radiated over the sample strike to the sample with a kinetic energy mv<2>. Since such neutral particles are not charged, they flow straightly without deflection in the magnetic field of the object lens, and irradiate the analysis point, or the electron beam radiating point accurately. Therefore, the gas and impurities attached over the sample 5 are removed, and a clean sample can be observed.
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