Separation of the Secondary Electrons from the Gamma Radiation near the Surface of an Encapsulated Gamma Source Using a Magnetic Field

Abstract

Secondary electron generation on the surface of encapsulated gamma sources can play a large role in the dose measured near the surface of the encapsulation. An experiment has been designed so that the gamma and electron components of the radiation dose can be measured separately, near the surface of an encapsulated 137-CsCl source. This is done using an electromagnetic field to bend the surface electrons away from the gamma dose measurement. Simulations using the Monte Carlo transport code PHITS show that a magnetic field of at least 75mT is needed to obtain a pure gamma measurement near the source.