A paper by Widom, Srivastava and Larsen [1] explores an old experiment that was reported in 1922 by Wendt and Irion, in which the two exploded tungsten wires by discharging a capacitor through them and afterwards saw spectral lines for helium show up. In addition to helium, lines for mercury and other unidentified elements were also seen. Wendt and Irion thought that the tungsten wires had completely disintegrated into helium. According to Widom et al., Rutherford did not think that the wires could carry enough energy to result in nuclear reactions. Rutherford also irradiated a tungsten target with a dilute beam of 100 keV electrons and saw no evidence for nuclear reactions.
A good description of the original experiment can be found here: http://www.levity.com/alchemy/nelson2_4.html I want to propose that what Wendt and Iron saw was the induced alpha decay of the tungsten wires, rather than the complete disintegration to helium: e- + 180W => e- + 4He + 176Hf + 2515 keV e- + 182W => e- + 4He + 178Hf + 1765 keV e- + 183W => e- + 4He + 179Hf + 1673 keV e- + 184W => e- + 4He + 180Hf + 1649 keV e- + 186W => e- + 4He + 182Hf + 1116 keV The mercury might have built up through a series of reactions along the following lines: 4He + 186W => 190Os - 1400 keV 4He + 190Os => 194Pt - 1500 keV 4He + 194Pt => 198Hg - 1400 keV Since these are all endothermic reactions, the only way for this to have happened would be if the alphas had sufficient energy, which they would have, according to the first set of reactions. Eric [1] http://arxiv.org/pdf/0709.1222.pdf
