Geiger counters and Radon detection

It is that time of the year, and I’ve been in touch with a number of people who I’ve not spoken with in months (in some cases since the same time last year). And a few asked me about Geiger counters, and radon detection that I’d written about in the last few posts.

TL;DR

Geiger counters aren’t a good way to measure household radon concentrations. But read on if you want to know more.

Geiger counters detect any form of radiation. The ones I was working with could detect α, β, or γ particles. That’s pretty much it. It tells you nothing about the source of the ionizing particle, its energy, or anything else. That’s it, it is a counter. It counts clicks per minute (CPM), and from that you can compute fancy things like sieverts an hour and such like.

Radon related problems are much more specific. There is exactly one decay of interest and that is the one from Radon to its decay to Polonium. The issue is that this Polonium is charged, and can adhere to dust and get inhaled. The health risk of radon is related to the concentration of Radon in the air, and there is no way to correlate CPM to Radon concentration.

So to get to Radon concentration, I’d have to go look at mechanisms based on alpha spectroscopy, or alpha track detectors, or traditional charcoal canisters.

That’s what I’m following up on now 🙂