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Low Level Radioactive Xenon
Monitoring by
Dr. Wolfgang Hennig,
Dr. William K. Warburton,
Business Official, bill@xia.com
DOE Grant No. DE-FG02-04ER84121
Amount: $750,000
The detection of dilute radioactive xenon isotopes in the
atmosphere is an important component of both national and international efforts
to detect clandestine underground nuclear weapons tests. Pacific Northwest National Laboratory has
developed an Automated Radioxenon Sampler/Analyzer (ARSA) that concentrates Xe
from the atmosphere and then counts it using a nuclear beta-gamma coincidence
counter. Although extremely sensitive,
this system employs 12 photomultiplier tubes to count 4 sample cells and
requires far more complex calibration and gain stabilizations efforts than would
be compatible with remote, unattended operations. Therefore, this project will construct a
composite “Phoswich” scintillator by joining a fast plastic scintillator for
beta detection to a slow CsI(Tl) scintillator
for gamma-ray detection, and coupling this composite to a single
photomultiplier tube. Phase I demonstrated that a phoswich detector and
digital signal processing could be used to detect beta-gamma coincidences
characteristic of Xe radioactive decay, achieved energy resolutions equivalent
to typical CsI detectors, and found an upper limit for wrongly detecting
coincidences of 0.1%.
Commercial Applications and Other Benefits as described by the awardee: An upgraded
ARSA system would be a key component of the