By my calculations, under some reasonable assumptions, the 'demon core' at the time was still a ~16.9 GBq alpha and gamma emitter when not undergoing a chain re

By my calculations, under some reasonable assumptions, the 'demon core' at the time was still a ~16.9 GBq alpha and gamma emitter when not undergoing a chain reaction (maybe more since its earlier criticality accident may have meant it had a higher proportion of shorter half-life elements). Calculation: Assuming 7% Pu240, 93% Pu239, (-(log 0.5 / (6560 * 365.25 * 24 * 3600)) * 6.02214076E23 / 240 * 0.07 -(log 0.5 / (24100 * 365.25 * 24 * 3600)) * 6.02214076E23 / 239 * 0.93) * 6.2 / 1E9 = 16.89 GBq. Admittedly, in the scheme of things, that's not that high, but criticality aside, handling it unshielded on a regular basis is not something that would be considered acceptable these days, especially not for a 'demonstration'. In 2023, when a 19 GBq sealed source (i.e. only slightly more activity) was lost in Western Australia when it fell from a truck, it sparked a massive search of a vast region, and the public were warned to keep a distance of 5 m. Obviously, they were worried someone would put it in a pocket or something for an extended period of time, and brief exposures wouldn't be that significant - but industrial radiographers working with similar sources, for example, would not get close to the source while it is unshielded and open.