Abstract
We report on the retrofitting of a standard DP2 environmental radiation monitor replacing the photomultiplier tube with a silicon photomultiplier (SiPM). The use of a SiPM has several advantages for a hand-held radiation monitor, including convenient low voltage operation and physical robustness. The SiPM is used to replace the existing photomultiplier tube, and we report the detection efficiency and alpha/beta discrimination performance of the modified probe compared to an unmodified version.