In-Chamber Vacuum Gage Calibration Method and Its Application to Cryopumping Measurements

摘要

The report describes a method of calibrating mass spectrometers and ion gages for pumping speed measurements. Sensitivity factors and pumping speed constants are determined from an analysis of the chamber pressures during gage calibration and pumping speed measurements. The CO2 sensitivity factor for the ion gage or mass spectrometer is obtained. The pumping speed constants were determined from the gage readings versus gas throughput. The method was applied to both ion gage and mass spectrometer measurements in determining the pumping speed of a 77K surface for 300K CO2, and approximately the same value of pumping speed was obtained for both gages. (Author)