Steady-State Sensitivity of a Vacuum Bolometer

Abstract

The theory of the steady‐state sensitivity of a vacuum bolometer as a function of operating temperature has been developed from exact heat flow equations which take into account losses by wire conduction as well as by radiation, and increase of bolometer resistance with temperature. Sensitivities predicted by the present theory differ by more than 50 percent from those computed from an earlier theory in which the effects of wire conduction and of increase of bolometer resistance with temperature were considered negligible. Experimental sensitivities determined with a test bolometer show good agreement with values calculated from the present theory, particularly in the region of optimum sensitivity where deviations are of the same order as experimental errors. The method of extending the theory to predict steady‐state sensitivities of bolometers which are not operated in vacuum has been illustrated for the pressure region in which free molecule conduction predominates.