Gnorts, Piantelli's theory of NiH reactions involves the nuclear capture of a H- ion by Ni and the resulting emission of alphas, protons and Auger electrons. This video:
http://www.youtube.com/watch?v=Efgy1bV2aQo has an excellent demonstration of alpha emission by radium gas within a cloud chamber. The beginning shows natural background radiation. Enjoy! http://www.youtube.com/watch?v=Efgy1bV2aQo T
