Shielding of skyshine interference with radiation detection systems

Skyshine, the radiation scattered from the air above a source, such as radiography or x-ray imaging systems, can be a problematic source of background gamma rays that interfere with radiation detection systems even at very large distances. The effects of skyshine have been studied for many years, but almost entirely within the context of nuclear power and radioactive waste storage. These earlier studies show that modeling of skyshine is made difficult because it must take into account huge volumes of space in the models that slow analysis significantly. This paper reports on results from various modeling and measurement efforts that examine shielding approaches to the skyshine interference problem with radiation detection systems.