This is cool. This guy makes a radiation detector without a Geiger tube, using other sensors that you might not think of. He also wrote software for it that is a free download.
The webinar starts around 10 minutes into the video. For the first 10 minutes he is having a problem with a mute button or something. So just skip to there.
Charting The Unquenchable Investor Thirst For Kool-Aid
10 minutes ago