| 摘要 |
A sensitive radon monitor has a container with a flat bottom and an upwardly and outwardly extending truncated conical side wall terminating upwardly in a relatively large upper edge. A cover overlies the upper edge. The cover has a disk-shaped plate with holes in a circular arrangement. A filter is placed atop the disk and a retainer ring overlies a peripheral portion of the filter and the disk. A negatively charged electret is held against an underside of a central position on the disk, and a detector is held upward against the electret. A second positively charged electret lines the inside of the cup-shaped base. Ambient gases flow into and out of the container through the filter and through the holes in the cover disk. The filter removes liquid and solid particles flowing through the opening establish an equilibrium. Radon decays within the chamber and positively charged products of the decay are attracted and repelled toward the first electret and toward the detector. The positively charged particles are held on the detector while they decay. Later, the detector is removed and is studied for evidence of decay of charged particles repelled toward, attracted to and held on the detector by the electret combination. The container is portable and can be used as a badge for miners or as a radon detecting device in buildings.
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