부산대학교 도서관

Expected backgrounds for electrostatic PIN-diode radon-emanation systems consist of three basic terms: a grow-in term, due to radon emanating from the detection chamber itself; a decaying term, due to radon that is transferred into the chamber along with radon from the sample; and a term constant in time due to environmental backgrounds such as cosmic rays. The first two backgrounds should produce energies corresponding to the radon-daughter peaks, while the third is expected to produce a continuous energy spectrum. To determine what is the dominant background for the South Dakota Mines emanation system, many background runs were co-added. Results indicate that environmental backgrounds are small, producing < 0.28 counts/day at 95% confidence in the 214Po energy region of interest (ROI). The grow-in and decay terms are 2.01±0.39 counts/day and 0.95±0.15 counts/day respectively in the same ROI (for the best-fit value for environmental backgrounds). The decay term is larger than expected, so a cold radon trap is now being used to attempt to reduce it. [ABSTRACT FROM AUTHOR]