Alpha, Beta & Gamma Radiation - Teaching Aid

[puncheex]

I don't think you're beta particle analysis is the case. It makes no difference, as far as I know, whether that aluminum sheet were, say, a ceramic tile of equivalent density. What stops betas, just like alphas, is the loss of kinetic energy through ionizing collisions with the atoms in the shielding. I don't think it has anything to do with the ability to conduct electricity or not.

[viptutorialscom]

Very cool since Alpha is an uncharged He (size a lot larger then e- or photon).

B- (electron emission) small and neg charged, will pass paper but will get "consumed" aluminum.  Here is why: Aluminum is a conductor (any conductor will have outer-most shell e- roaming free throughout it). e- striking such surface could be compared to charging of the AL surface with additional e-.

Gamma being a high energy particle of negligible mass (photon), will stop on lead & cause E transfer to e- excitation