Fig4_4 Nuclear transformation

Fig4_4 Nuclear transformation

Fig. 4.4 . When an alpha particle, or helium nucleus denoted 4He, is sent through a cloud chamber, it usually passes right through it, with a trajectory that marks out a straight line. Very occasionally, the alpha particle will strike the nucleus, 14N1, of a nitrogen atom in the air within the chamber, transforming it into the nucleus, 17O, of an oxygen atom with the emission of a proton, the nucleus of a hydrogen atom and denoted 1H. Such a nuclear transformation was first observed in cloud chamber photographs taken in the early 1920s by Patrick Blackett (1897-1974).

Copyright 2010, Professor Kenneth R. Lang, Tufts University