Effect of Scattering Neutrons on Induced Radio-activity

Abstract

M. DANYSZ, J. Rotblat, L. Wertenstein and M. Zyw¹ have found that iodine and silver exposed to neutrons acquire a stronger radioactivity if the neutrons are allowed to pass through lead or gold. We have investigated further this effect using different substances as scatterers, in the form of cylinders of 55 mm. height and 24.5 mm. diameter, with a coaxial cylindrical hole of 7 mm. diameter for the source of neutrons consisting of 35 millicuries of radon mixed with beryllium. Silver tubes of 25 mm. inside diameter were placed around the cylinders for activation. In this arrangement, practically all primary and scattered neutrons pass through the receiver. For comparison, source and receiver were placed in exactly the same positions but without any scatterer. With all substances we have found that the activity is increased, the effects ranging from a few per cent to about 18 per cent.