Avalanche Diode Low Energy X-Ray and Nuclear Particle Detector

Avalanche diodes which are sensitive enough to detect low energy x-rays and beta particles have been fabricated and tested. They operate at room temperature and their structure is based on large area avalanche photodiodes. X-ray response has been measured over the energy range of 4 keV to 26 keV. At 5.9 keV a FWHM of 10% was obtained. In addition, multi-element sensors have been fabricated. Beta particles were detected from a variety of isotopic sources including C1-36, Sr-90, C-14 and H-3. The tritium beta particles, with 5 keV average energy, were detected with a 20% counting efficiency from a calibrated source. Tritium beta particles from biological samples were also measured. The high sensitivity to low energy x-rays and beta particles makes this detector useful for many industrial, military and commercial applications, and in particular for biomedical research.