ABSTRACT
This chapter discusses the background radiation and methods to reduce its impact are the subject. It also discusses the background for gamma-ray and primarily considers x-ray measurements. The minimization of this reflection contribution when the detector must be shielded from background radiation is considered. As background radiation incident on the walls of the counting cavity is attenuated, it also creates a buildup of secondary radiation in the form of Compton scattered photons, bremsstrahlung, and x rays. The alpha particles emitted by these airborne radionuclides are of little concern in most radiation measurements except in the case of alpha-particle spectrometers for which they contribute to the energy spectrum. Although sources of high-energy photon radiation are usually well shielded horizontally by thick building walls, they often have limited shielding provided by a roof and, hence, radiation escaping upwards can scatter in the atmosphere and contribute to the background radiation at locations far removed from the radiation facility.
