Skyshine Contribution to Gamma Ray Background Between 0 and 4 MeV

Mitchell, Allison L. ; Borgardt, James D. ; Kouzes, Richard T.

Pacific Northwest National Laboratory (U.S.)

关键词: 46 Instrumentation Related To Nuclear Science And Technology;    Cosmic Rays;    Solar Radiation;    Gamma Ray Background;    Gamma Radiation;   

DOI  :  10.2172/990599
RP-ID  :  PNNL-18666
RP-ID  :  AC05-76RL01830
RP-ID  :  990599

美国|英语

来源: UNT Digital Library

【 摘 要 】

Natural gamma-ray background is composed of four components; which include cosmic rays, cosmic ray produced atmospheric activity, terrestrial sources, and skyshine from terrestrial sources. Skyshine is radiation scattered from the air above a source that can produce a signal in radiation detection instrumentation. Skyshine has been studied for many years but its contribution to the natural background observed in a detector has not been studied. A large NaI(Tl) detector was used to investigate each of the four components of the natural background using a series of 48-hour measurements and appropriate lead shielding configured to discriminate contributions from each component. It was found that while the contribution from skyshine decreases rapidly with energy, it represents a significant portion of the background spectrum below ~500keV. A similar campaign of measurements using a HPGe detector is underway.