Scattering of Fast β-Rays

IN two previous notes¹ some results have been described which were obtained with a beam of fast (β-rays (1500 < E < 3000 ekv.) in a nitrogen-filled expansion chamber. It is clear from the photographs that these β-rays are considerably scattered in the gas. By selection of those cases where there is a perceptible change in the direction of path (whenever the deflection exceeds 20°) and by measurement of the angle of deflection with a Pulfrich stereo-comparator, Curve I in Fig. 1 was obtained for the single scattering in a gas at angles greater than 10°-20°.