At 11:45 AM 12/7/2009, Terry Blanton wrote:
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:
http://www.springerlink.com/content/022501181p3h764l/
The critical triple tracks are those which are generated where the
alphas can't penetrate.
The caption for a photo in the article seems to claim that there is a
triple track from exposure to Am-241. But that's an isolated track
and could be from cosmic ray background. I have some question about
how easy it is to find triple tracks when they are scattering down
into the material, as distinct from being generated deep in the
material, almost before the neutron would have exited. Triple tracks
would be generated at all depths in the detector at roughly the same
rate, but the most beautiful photos of them show converging grooves
at the bottom of the constellation of three pits. This has to has to
be an image of the triple track from the back side of the detector.
If it had been the front side and a three-lobed track were observed,
the point of original would have been completely etched away.
