Low-cost of-the-shelf SiPin photodiodes such as the BPW34F which have been featured in many DIY projects over the years seems the obvious choice. However these require significant amplification, very noisy and very susceptible to RFI. So can only be practically used as a simple gamma counter, with no energy resolution and has very low sensitivity having a very small aperture.
There are also specialist SiPin Photodiodes designed specifically for gamma ray and xray detection, but these are very expensive and difficult to source in small quantities. So the next best candidate are the medium range detectors usually with a 10mm x 10mm aperture. Current detectors I am testing include:
- Manufacture First Sensor Part # 5014450 - has visible light filter
- Manufacture First Sensor Part # PS100B-7-CERPINE - has visible light filter
- Hamamatsu Part # S3590 - no visible light filter
New part : as used in the Cosmic Pi 3x3mm Silicon PhotoMultiplier (SiPM) Manufactured by AdvanSiD - Part number - ASD-RGB3S-P, ASD-NUV3S-P this detector has to be used with a larger plastic or crystal scintillatior.