Application of flash desorption spectroscopy to pressure measurement in extremely high vacuum

Abstract

Flash desorption spectroscopy (FDS) was applied to measure pressure in the range of extremely high vacuum (XHV). After adsorption of hydrogen gas on a clean tungsten filament, in an XHV chamber made of aluminum alloy, the pressure rise during flash heating of the filament was measured by an extractor gauge (EG). The pressure rise was observed to be linearly proportional to the exposure to hydrogen in the pressure range 5 × 10 −10−2 × 10 −8 Pa. The pressure in the chamber was expressed as a function of the pressure rise. For the lower pressure range, the same technique was applied to the adsorption of the residual gas. The pressure rise was bserved again to be approximately proportional to the pressure in the chamber, even in the range of 10 −10 Pa. Since the linearity between the pressure rise and the chamber pressure may be extrapolated to the lower pressure range of 10 −11 Pa, the present FDS technique can be applied to pressure measurement in the range of 10 −11 Pa.