ENHANCEMENT OF THE SENSITIVITY OF AN IONIZATION TYPE SEMICONDUCTOR PHOTOGRAPHIC SYSTEM

The investigation of the sensitivity of a ionization-type semiconducto r photographic system with high-resistivity cathode of large diameter (40-60 mm) is described. A photosensitive GaAs cathode with a resistiv ity of 10(6) Omega cm, has been studied. With a gas discharge gap form ed by a dielectric separator with the thickness ranging from 40 to 60 mu m, a discharge has been formed in air at pressures from 20-760 Torr . The cathode was irradiated on the back with light in a particular wa velength range that mns used to control the photoconductivity of the m aterial. The semiconductor material was found to stabilize the dischar ge. A local change of tile resistance inhomogeneity is determined by a local change of discharge radiation intensity. The assessment of the resistance distribution is then based on analysis of the discharge rad iation, visualized by a photograph taken through the SnO2 film. Means of increasing the sensitivity and improving the working characteristic s are proposed.