High dose-rate gamma radiation response of commercial off-the-shelf diodes

Abstract

Ionizing radiation plays a vital role in numerous applications, such as radiation safety, industrial monitoring, and medical dosimetry. This study evaluates the performance of four commercially available off-the-shelf (COTS) rectifier diodes—1N4007, UF4007, BY203–20S, and GP02-40—as detectors for high dose-rate gamma radiation, using a Cobalt-60 source. Their sensitivity, its variation with accumulated dose (SVWD), and with temperature (SVWT) were assessed using an ionization chamber as a reference dosimeter. The results indicate that two diode models exhibit promising performance for dosimetric applications. In fact, the BY203–20S and UF4007 showed a sensitivity ~7.5 times higher than the ionization chamber, and minimal sensitivity variation with accumulated doses (~5 % and ~2 %) up to 23 and 33 kGy, respectively. The 1N4007 demonstrated the highest sensitivity (~9 times higher), but also the most significant sensitivity decay, ~-13 % at 22 kGy. In contrast, GP02-40 diode exhibited the lowest sensitivity, the greatest sensitivity decay, and the lowest reproducibility among the tested samples. Thermal compensation procedures have been applied to the diode dark current and SVWT, monitoring in real time the device temperature with the UF4007 as sensor. Around +0.4 %/◦C of increase in relative sensitivities were measured for BY203–20S and UF4007 diodes, highlighting the relevance of compensation the temperature effects for accurate measurements. These findings suggest that low-cost rectifier COTS diodes may serve as viable candidates for high dose-rate radiation detection as compact and affordable devices.