Personal alpha dosimetry and measurement of exposure to radon and thoron progeny and long-lived radioactive dust
- Canadian Inst. for Radiation Safety, Saskatchewan (Canada)
Personal alpha dosimeters are used in Canadian uranium mines and mills to monitor workers for exposure to radon and thoron progeny and Long-Lived Radioactive Dust (LLRD). Personal alpha dosimeters commonly used in Canadian uranium mines consist of a solid-state nuclear track detector (SSNTD) mounted in a battery operated air pumping system. The SSNTD system utilizes LR 115 Type II film as a detector which provides a permanent record of the exposure. The film is mounted inside a specially designed non-electronic spectrometer which consists of a collection filter, and a series of collimators fitted with energy absorbing materials of precise thicknesses. The spectrometer isolates the alpha particles emitted by radon and thoron progeny into separate and readily identifiable irradiated regions on the LR 115 film. After chemically etching the film to enlarge the tracks made by alpha radiation, the concentrations of radon and thoron progeny can be computed directly by optically counting the number of tracks created on the film. The lower limit of detection for the personal alpha dosimeter is between 4 and 5 mWLM and is based on a one month operation period at a nominal air flow rate of 4 L h{sup -1} through the SSNTD. LLRD measurements are obtained by performing standard gross alpha counts of the collection filter inside the SSNTD. The Minimum Detectable Amount (MDA) for the personal alpha dosimeter was calculated to be between 0.04 and 0.06 Bq m{sup -3} depending on the counting period. Comparative studies of the SSNTD measurement of radon and thoron progeny have been carried out at the United States Environmental Measurements Laboratory (EML) in New York, at the LANMET Radon/Thoron Chamber in Elliot Lake, Ontario, Canada, and at the CAIRS Radon/Thoron Calibration Chamber in Saskatoon, Saskatchewan, Canada.
- OSTI ID:
- 394054
- Report Number(s):
- CONF-9607135-; ISSN 0017-9078; TRN: 96:028732
- Journal Information:
- Health Physics, Vol. 70, Issue Suppl.6; Conference: 41. Annual Meeting of the Health Physics Society, Seattle, WA (United States), 21-25 Jul 1996; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Intercomparison of active and passive instruments for radon and radon progeny in North America
Personal computer programs for use in radon/thoron progeny measurements