PRIMARY ION MONITOR FOR ANALYZER OF MASS OF SECONDARY ION

摘要

PURPOSE:To detect the total volume of primary ions accurately by a method wherein a mechanism for making variable the electrode plate position is provided in such a way that the mechanism can convert the cores of an aperture and a primary beam into those concentric and non-concentric. CONSTITUTION:In place of a beam shutter by the prior art, a variable mechanism 8 using an air cylinder as an aperture electrode 5 is used. By this variable mechanism 8, an aperture 5 and a primary ion beam is made concentric in the first state. In the second state, a monitor electrode is moved so that the electrode plate provides a condition in which the whole primary ion beam is screened, while the whole primary ion beam is monitored by the aperture electrode 5, allowing the volume of the beam to be displayed by an indicator 6 via an insulating material 10. By so doing, the deterioration of an ion source, reduction in trucking efficiency and so on are readily monitored. Furthermore, the mechanism incorporating the beam shutter will contribute to the simplification of the apparatus.