You are correct, the cosmic rays you see in a cloud chamber are typically muons (and its pretty easy to make one with stuff you can get at the drug store (or ap

You are correct, the cosmic rays you see in a cloud chamber are typically muons (and its pretty easy to make one with stuff you can get at the drug store (or apothecary if you're outside the US :-)). If you want to see the higher energy ones then shielding helps.