On Thu, Jul 11, 2013 at 11:28 PM, Eric Walker <[email protected]> wrote:
> On Thu, Jul 11, 2013 at 12:11 PM, H Veeder <[email protected]> wrote: > > How many well known collisions produce outgoing particles who kinetic >> energy is approx. 100 times that of the incoming particles? >> >> Can it be compared with known collisions? >> > > It was closer to 15,000 times the original energy (5,000,000 eV / 350 eV), > after having traversed ~1 um of titanium (or, possibly, some daughter > particle resulting from a chain reaction of some kind that occurred closer > to the exiting side of the foil). The presence of the foil complicates > things, because it's not clear how far the daughter had to travel through > it. The longer it had to travel, the more it would slow down, I think, > especially if it was not initially aligned along an open pathway in the > crystal structure. > > Thanks for the clarification. I knew it was large, but since I couldn't immediately recall the figures I deliberately under estimated. > The authors speculated that the mystery particle was tritium on the basis > of the energy difference in the energy peak when the 200 V detecter bias > was turned off (silicon surface-barrier detector spectra respond to changes > in voltage, apparently). The authors did not offer a possible reaction. > > Another possibility apart from a nuclear reaction was that background > radiation was mistakenly associated with the incoming beam collisions. > They only saw events in four of nine experiments, and the particles could > have been cosmic rays or something similar. Also interesting is the fact > that there was an earlier experiment by a group in Germany with a very > similar setup that I just read about, and they saw nothing that could not > be explained by normal dd reaction cross sections. But I don't think they > saw anything above noise in the 300 eV range, and their foils were 3 um > thick. > Assuming it is a real anomaly, it suggests a memory effect whereby each incoming particle serves to nudge the nuclei closer together. Harry > > > Eric > >
