OP should not be messing with one of the smoke detectors mandated to protect an area.

I certainly hope that she obtained a seperate smoke detector specifically for these experiments. IMO, any smoke detector which has been modified in any way should not be used for life safety.

Regards the radioactive stuff, don't smash the smoke detector, and if you do, don't eat the parts or breathe the dust. If you burn it, don't breathe the smoke; it may contain lead (Pb).