The Thermopile for an Infra-red Spectrometer and its Application to a Vacuum Gauge

(1) The thermopiles have been constructed by depositing Bi-Te and Bi-Sb on thin colodion films by vacuum evaporation. (2) Thermoelectromotive force of the Bi-Te junction was measured as 450μV/℃ while that of the Bi-Sb, 120μV/℃. (3) Owing to the small heat capacity, the thermopiles were found to produce an oscillating thermoelectric power by the irradiation of the chopped infra-red ray. (4) The time constant was measured by observing the oscillating thermoelectric power in various chopping frequencies, and was given as 3/100 sec. (5) By evacuating the tube of the junction, the saturated thermoelectric power increased about 20 times. (6) The time constant also increased with equal proportion except a small discrepancy in high chopping frequency. (7) The change of characteristics due to the blackening was investigated. (8) Using the Bi-Sb junction, a convenient vacuum gauge has been constructed. In conclusion, the writers wish to their sincere appreciation to Dr. J. Okubo, the ex-superintendent professor of this institute, for his kind interest through the whole course of this work