Well, radiation sources are a little more common than one might think, even today. I have half a dozen in my home -- smoke detectors, tritium lights. That may

Well, radiation sources are a little more common than one might think, even today. I have half a dozen in my home -- smoke detectors, tritium lights. That may be in things people don't even expect. Objects made out of uranium glass may set off a Geiger counter. A lot of watches have tritium dials, and older ones have radium dials (a serious risk, unlike tritium). Quite a few people have something radioactive in their jewellery or keepsake box somewhere. A relative gave me his old US Army compass, and one day while re-examining it I noticed the marking on the back: https://i.imgur.com/CLT98kI.jpg https://i.imgur.com/CLT98kI.jpg 130 millicuries of tritium at manufacture. And sure enough, the dial is still very faintly lit some decades later (tritium half-life is about 12 years), though it takes total darkness to see it at this point. Of course any ionizing radiation outside of the tritium-containing glass means something has gone terribly wrong. But when your experiments, and security precautions, are all sensitive to any sort of radiation, I can imagine wanting to keep it off-site.