-----Original Message----- From: Terry Blanton > I am interested in only the *triple tracks* for now.
They also got triple tracks from 5.5 MeV alphas from Am; but, of course, that is 4 times the mass of the single neutron: ... not to mention, the alpha is a charged particle. What would be the threshold energy for an alpha to impinge on 12C ? (unless there is a spallation neutron intermediary) The chart that Horace found does make a prima facie case for fast neutrons, since the cross-section has increased by two orders of magnitude compared to lower energy neutrons - but it still appears to be too low to happen the 10 times per run, based on the tritium inventory in the small cell that they have reported in earlier experiments. I'm still trying to get a handle on the required flux to result in 10 triple tracks but think it would be much higher than can be possible. The .3 barns is about the same cross-section as the hydrogen atoms in the water of a fission reactor, which does become slightly activated over years of time in the confines of a reactor, in a flux that is typically 10^14 neutrons per cc... but that may not be a good indicator to compare with a thin piece of CR-39 over three days in a flux that should be about 10^13 times less. Triple tacks from another alpha interaction, unless that alpha first creates a fast spallation neutron, as Robin suggested seems remote - and even then, the needed flux just isn't there to make it work out statistically IMHO. All in all, I am still of the opinion that the triple tracks are not indicative of a three-alpha reaction (12C fission), and that alternatives should be looked at. Jones
