The Calculation of Gamma Ray Penetration of the Walls of Cylindrical and Conical Collimating Holes

Abstract

~XTRODUCTIOSA CYLISDRICAL or conical hole in a block of high density material is commonly used as a diaphragm for the definition of an x-ray beam or in conjunction with a gamma-ray detector to define the solid angle of radiation which may reach the detector.The diaphragm, however, cannot be considered ill every case t o limit the radiation passing through the hole t o t'hat defined by the geometrical factors, i.e. hole diameter, length and position of source relative to the diaphragm, and shape of the source, since radiation may penetrate through the diaphragm edges or be scattered by the diaphragm wall.I n a detection system such as a collimated scintillation counter, the diameter of the crystal is usually larger than the diameter of the collimating hole.