ULTIMATE SENSITIVITY AND PRACTICAL PERFORMANCE OF THE TELLURIUM PHOTOCONDUCTIVE DETECTOR*

Abstract-Calculations of the ultimate sensitivity and measurements of the practical per-formance have been made for the tellurium photoconductive detector. For the condition that detector sensitivity is limited by fluctuations of background radiation, the theoretical NEP (noise equivalent power) at the peak of spectral sensitivity (X = 3.4 p) was calculated to be 5.1 x IO-i3 W. For the “best ” tellurium detector the measured value of NEP was 3.1 x lo-i3 W at the same wavelength and at the optimum chopping frequency. These values indicate that the tellurium photoconductive detector is background limited and therefore is ideal