GB870652A - Radiant energy meter - Google Patents

Abstract

870,652. Radiant energy detectors. COLMAN, R. March 11, 1959 [March 14, 1958], No. 8476/59. Class 40(3) A radiant energy detector comprises a photosensitive device PC (Fig. 1), the resistance of which is related to the intensity of incident radiant energy and determines, together with the voltage derived from a potentiometer P 1 , the voltage applied to a neon type indicator I, so that by adjusting P 1 to extinguish the indicator, comparative or, with suitable calibration of P 1 , absolute measurements of the intensity of incident radiant energy may be made. In the arrangement shown the operational voltage is derived from an A.C. source connected at a, a, via a voltage doubling circuit D 1 , D 2 , C 1 , C 2 and a smoothing circuit comprising R 1 , R 2 and a gas discharge stabilizing tube T 1 . Any suitable power supply may be employed instead of the arrangement shown the elements R 1 , R 2 and T 1 , however, being retained if a battery supply is utilized. All of the components of Fig. 1 may be mounted in an enclosure Fig. 2 (not shown). The photosensitive device PC may be connected in series with the slides of potentiometer P 1 and the indicator I 1 (Fig. 4A, not shown), or in parallel with the latter (Fig. 4B, not shown). The photosensitive device PC may be either a photoconductive or a photovoltaic device operated as a variable radiant sensitive impedance and the range of the instrument may be made to include any section of the radiant spectrum including the X-ray and gamma ray regions.