Eric-- I think the key to looking for beta+/beta- annihilation is to do co-incident counting in detectors looking for photons coming in opposite directions (from a single point) and to look for radiation of any wave length and above--say 50 ev. The annihilation photons come off back-to-back. I did this experiment on a radioactic sodium isotope that decays by beta+ emission to determine the rest mass (energy) of an electron in 1959. It was quite an accurate experiment. The photons will loose energy as they pass by atoms with electrons in any shield. The denser the material the quicker the loss of energy. Until they get to real low energies they mostly move in a straight line. Thus even shielding will not destroy the coincident events that detectors will record.
Bob ----- Original Message ----- From: Eric Walker To: [email protected] Sent: Friday, March 21, 2014 11:10 PM Subject: Re: [Vo]:My current views on the 'Rossi's process' On Fri, Mar 21, 2014 at 7:54 AM, Teslaalset <[email protected]> wrote: 1.. The ß+ decay energy of Cu(x) > Ni(x) + e+ + ve (2 -4 MeV) of each decay step in the chain, causing the Ni/Cu powder to heat up. I think the electron-positron annihilation photons from the radioactive decay of certain isotopes of nickel would escape the system. Since the mean free path of these photons is long, they would be unlikely to thermalize, unless some sort of 100 percent efficiency gamma thermalization mechanism is at play. (Only handfuls of gammas are typically seen.) Eric
