Abstract
It is known that when the mean free path of the gas molecule is sufficiently large compared with the thickness of the surface layer surrounding a body placed in the gas, the heat loss by thermal conduction through the gas is proportional to the pressure. Therefore in a low pressure region, the temperature rise of a constantly heated body in the gas depends upon the pressure. The thin-plate vacuum gauge here reported is based on the above mentioned phenomenon.
The vacuum gauge examined is composed of a thermopile attached to a thin long rectanguler mica plate, with a heating wire near one end of the plate. The measurable range with the unwrapped sensing part seems to be almost the same as that with a usual gauge of thermal conductivity type. The range with the wrapped sensing parts is ca 5×10-4∼1×102 Torr. The vacuum measurement is done by a temperature difference less than 30 degrees.
