| 摘要 |
PURPOSE: To easily lower the lower limit of measurement by soft X-rays, and accurately measure gas pressure by forming a metallic net ion collecting electrode (collector) out of fine wires. CONSTITUTION: Gas coming in toward a vacuum gauge from a vacuum device, is ionized by an ion source 16, goes in the inlet 14 of an energy analyzer 13 composed of paired coaxial semi-spherical surfaces (inner side electrode 3 and outer side electrode 4) through both a hole at the lower section of a grid 2 and the hole of a bulkhead 8, only ions of specified energy can pass through the analyzer 13, and the ions come in a metallic net collector (metallic net ion collecting electrode) 5 formed out of fine wires. The quantity of X-rays coming in the collector 5, is proportional to the projected area of the collector when it is viewed from the outlet 15 of the analyzer 13, however if the collector 5 is formed out of fine wires, its projected area can be reduced to roughly 10% of a metallic disc identical in outer diameter. Therefore, the quantity of soft X-rays coming in the collector 5 can be reduced to a level of 2×10-13Pa, and gas pressure in a vacuum can thereby be accurately measured to a level of 10-13Pa.
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