Some Interesting Tracks of Alpha Particles in Gases

Abstract

SELECTED photographs taken from about ten thousand exposures show a number of types of alpha ray tracks, some of which have been described before and some have not. Fig. 1 gives a track in which it is apparent that the alpha particle hits the nucleus of an oxygen or nitrogen atom. The nucleus is projected forward at a very high speed, while the alpha particle is reflected backward at a sharp angle. In Fig. 2 the track is an almost straight line with a branch which goes off at an angle of about 8°. In some instances the branch is at an angle as great as 50° with the straight track. An example of this is given in Fig. 3, though in the plane of the photograph the angle is only 40°. In some instances another type of track is given, in which one of the branches is very short, the other very long. It is not unlikely that some of the longest tracks are due to hydrogen nuclei. A discussion of the tracks will be published very soon in one of the physical journals. All the photographs were taken by the Shimizu-Wilson method, by means of which many more photographs showing views at right angles will soon betaken.