The Scottish Boinc Team

If you plan to run Radioactive@Home on a WIndows systems, you can buy a GMC-300E detector on Amazon and use it with the project. It's not plug and play though. It requires installing custom app files, similar to installing optimized project programs, setting the correct com port number in a file and manually opening the com port on the detector the first time and when ever system reboots. It's easy.

Full instructions here...download and unzip the contents onto your computer. Follow the Radioactive_GMC300E_readme.pdf guide. Worked for me.
Radioactive@home gmc-300.zip