Abstract
Avalanche diodes, up to 20 mm2 in area, have been made with sensitivities up to 6 × 106 counts/ Roentgen. Operating at 200 volts, typical gains of 20 are achieved. This permits the detection of 6 keV X-rays and dosimetry of gamma rays down to 30 keV with background counting rates of about 0.1 c/s.