If you’re good Santa might bring you some for Xmas (not sure I’d call them compact though)
I confess I have a soft spot for the muon (the particle, not the speaker which TBH I didn’t like when I heard them) - a sort of turbo-charged electron which is heavy enough to get close and personal with the nucleus (it can catalyse cold fusion that way). It’s a shame it’s so short-lived. But if we accelerate it up to close to light speed then its lifetime is extended in our frame of reference by relativistic time dilation. This is one of the clearest and (relatively) simplest ways of showing this effect (none of that malarkey with trying to fly ultra-precise ultra-delicate atomic clocks around the earth on aircraft).