Undoped InSb Schottky detector for gamma ray measurements

Using an undoped InSb Schottky detector, the energy spectra of the gamma rays of ²⁴¹Am and ¹³³Ba were measured. For the measurements of X-rays and gamma rays with better energy resolution and higher efficiency than conventional semiconductor detectors such as Si and Ge detectors, we are studying InSb radiation detectors. Until now, we fabricated p-InSb Schottky type, pn junction type detectors, and undoped InSb Schottky type detectors with an electrode of 3 mm in diameter, and measured alpha particles of ²⁴¹Am. For the measurement of gamma rays, we fabricated undoped InSb Schottky type detectors with smaller electrode areas. Gamma ray signals were clearly separated from the background, and the difference between the energy spectra of ²⁴¹Am and ¹³³Ba gamma rays was observed.