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Forum: Film SLRs and Compact Film Cameras
08-14-2011, 01:19 PM
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The nuclei that are prodcued as a result of the alpha decay of thorium are themselves radioactive, they decay further in a number of steps to a stable isotope of lead. Some of the steps in the decay chain produce beta particles.
Still, because the half-life of thorium is very long (= rate of decay low) the resulting activity is low.
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Forum: Film SLRs and Compact Film Cameras
03-23-2011, 05:21 PM
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... or, in a wider sense the visible light is radiation as well. I guess 'radiation' is commonly used as a shorthand of 'ionising radiation' that is, particles and quanta that are energetic enough to mess with the electrons minding their own business whirring around nuclei making them atoms. This, in turn means that the chemical bonds binding atoms to molecules (making up us) might get broken (and so by extension may we); chemical bonds are about the outermost electrons of atoms interacting in ways that result in more or less stable arrangements of atoms where in the stable ones the little darlings have arranged themselves in a way that takes some energy to change (and therefore does not happen all by itself).
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Forum: Film SLRs and Compact Film Cameras
03-23-2011, 08:46 AM
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Thorium-232 is an alpha emitter with remarkably long half-life (14.05x1E9 years) which means very low activity / mass. Besides, as mentioned, the alpha particles do not tend to get far before colliding into other matter losing their energy and thereby the ability to do harm. Kind of like small shotgun pellets, essentially harmless at a bit of a distance (but still deadly at closer range), only the scale of things is so much smaller that thorium would need to be, essentially, in contact to tissue to do harm.
Actually, it might be kind of cool having one of these :)
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