Characterization of commercial off-the-shelf rectifier diodes as detectors for high dose-rate gamma radiation fields

Abstract

Accurate measurement of ionizing radiation at high dose rates underpins radiation protection, industrial sterilization, food irradiation, and advanced medical therapies, such as high-dose-rate brachytherapy and FLASH treatment. Detectors purpose-built for these intense fields are costly and complex, motivating the search for inexpensive and widely available alternatives that retain adequate sensitivity and long-term stability. This study evaluated four commercial rectifier diodes, 1N4007, UF4007, BY203-20S, and GP02-40, as detectors for high-dose-rate gamma fields from a 60Co source delivering 21.90 ± 0.11 kGy/h, benchmarked against a reference ionization chamber, with an embedded UF4007 diode providing in situ thermal correction of the dark current and sensitivity variation with temperature (SVWT) and dose (SVWD). The sensitivities of BY203-20S and UF4007 were nearly 7.5 times that of the ionization chamber, and they lost only approximately 5 % and 2 % of their responses at 22 and 33 kGy, respectively. The sensitivity of 1N4007 was almost nine times higher, but it degraded by approximately 13 % at 22 kGy. GP02-40 exhibited the poorest repeatability and stability. These findings show that the selected commercial diodes, once thermally corrected, remain operational across tens of kGy and provide accurate, low-cost, real-time detection of intense gamma fields.