X-RAY BEAM ELECTRON STREAM SETOFF METHOD AND HOT CATHODE TYPE ELECTRIC DISSOCIATE VACUUM METER USING THE METHOD

摘要

PURPOSE:To provide precise measurability for ultra-high vacuum by selecting negative bias on a screen grid installed between an anode grid and a collector, and cancelling the X-ray photo-electron beam. CONSTITUTION:Voltages of 300V and 150V approximately are impressed on a spherical grip 10 and filament 20, respectively, and an electron having hopped out of the filament 20 vibrates inside and outside of the grid 10 to generate pos. ions. These ions are accelerated by a neg. suppressor electrode and flow into an ion collector 33. The current flowing in this collector 33 is measured by an ammeter 60, and the pressure is determined. Meantime, soft X-rays generated when electrons bombard with the grid 10, are cast onto a collector plate of the collector part 30 to give ill affection to the pressure measurements. Therefore, a certain neg. potential is impressed to a screen electrode 100 installed over the collector plate, and thereby influence of the soft X-rays is removed to ensure that the pressure is measured accurately.