スピニングロータ真空計の圧力測定限界

抄録

The argon pressure measured by a spinnig rotor gauge (MKS SRG-2), P_SRG, has been compared to the pressure measured by an ionization gauge, P_IG. The linearity of P_SRG as compared to P_IG was previausly observed between 10^-1 and 10^-4 Pa using the average value of the residual drag, P_OFS, by other authors. In the present study, the value of P_OFS has been newly determined using data obtained in the range above 2×10^-5 Pa, where the fluctuation of P_OFS becomes relatively small. P_OFS was determined such that the standard deviation of [Log (P_IG) -Sa⋅Log (P_SRG-P_OFS) -Log (Sb)] was minimized. Here, Sa and Sb are constants and nearly equal 1. The linearity was found to extend to a lower pressure region using the P_OFS obtained in present method, as opposed to that obtained by the conventional averaging method. It was found that the standard deviation of P_SRG at constant pressure was proportional to T^-2.5, where T is a sampling interval used with the SRG. This relation is valid up to 10^-6 Pa.