A neutral pion decays into two gammas. In the rest frame of the pion, these are back to back and have energies of 67 MeV. I'm interested in the case where the pion's energy in the lab frame is on the order of a few hundred MeV. Can anyone point me to any source of information on what kind of experimental signature you would get from this in a laboratory experiment? These two gammas would probably interact through pair production, so then you'd have some high-energy electrons and positrons. After that, do you get a further cascade of gammas? Charged particles?