The Flash desorption (FD) technique was applied to measure the pressure in the range of extremely high vacuum (XHV). After the adsorption of hydrogen gas on a clean tungsten filament, in the XHV chamber made of aluminum alloy, the pressure rise during the flash heating for the filament was measured by an ionization gauge of the extractor type (EG). The peak value of the pressure rise, ΔP, was observed to be linearly proportional to the exposure of hydrogen gas at less than 0.15 L in the pressure range from 5 × 10
-10 to 2 × 10
-8 Pa. The pressure of the chamber was expressed as a function of the ratio between ΔP and exposure time, t
ad. For a lower pressure range, the same technique was applied based on the adsorption of the residual gas in the chamber. The pressure rise was again observed to be approximately proportional to the pressure of the chamber, even in the range of 10
-10 Pa. Since the linearity between ΔP/ t
ad and the chamber pressure may be extrapolated to the lower pressure range of 10
-11 Pa, the present FDS technique can be applied for the pressure measurement in the range of 10
-11 Pa.
抄録全体を表示