抄録
A new type thermistor vacuum gauge is described. In a thermistor, the electric resistance changes largely with its temperature, so that it can be used as a pressure sensitive elenent in a thermal vacuum gauge. Owing to a nonlinear relation between the temperature and electric resistance in a thermistor, however, the problem of the ambient temperature compensation in a thermistor gauge is very difficult. So a gauge of new type was designed, emploging two thermistors one of which is a monitor of gauge head temperature. The signal from the temperature monitoring thermistor drives a vacuum tube and control its plate current, the load of which is a nichrome wire winding around the gauge head. If the temperature of the gauge head is lower than the setting point, the plate current increases so that the temperature will be raised and vice versa, thus the gauge head is hold at a constant temperature irrespective of the ambient temperature. Some theoretical discussions concerning thermal vacuum gauge designs are presented. The measureable pressure range is 10 torr to 10-3 torr. Thermistor gauges of this type, together with Penning gauges and hot cathode ionization gauges, are now being used as pressure monitors in a vacuum system of a 1 Bev electron synchrotron at the Institute for Nuclear Study, University of Tokyo.
