In-situ passive monitoring of alpha-emitting radionuclides
- Oak Ridge National Lab., TN (United States)
- Landauer, Inc., Glenwood, IL (United States)
- Rad Elec, Inc., Frederick, MD (United States)
Electrets and alpha-track detectors (ATDs) show considerable promise for inexpensive passive monitoring of alpha contamination on man-made surfaces or in soil. At the stringent Department of Energy (DOE) limit of 100 dpm/100 cm{sup 2}, the electret voltage drops 10 V in about 4 hours; 10 V is readily quantifiable since any reading of electret voltage is accurate to {plus_minus}l V. An analogous signal-to-noise ratio for the ATDs is obtained after an exposure time of about 3 hours. The alpha-track registration efficiency for CR-39 type plastic is about 70% with the background track density averaging 13 tracks/cm{sup 2}. Measurements for intercomparison were performed with electrets, ATDS, and conventional survey meters on a contaminated vinyl floor and a concrete loading dock. Agreement between different types of detector readings was satisfactory. Surface soil measurements, using an exposure time of 1 day, can detect contamination of just a few pCi/g. Preliminary horizontal mapping was conducted within and at the boundary of a plutonium contaminated area at the DOE Nevada Test Site (NTS). The means of making vertical profiles of subsurface contamination are being explored. Some problems that have to be overcome involve interference from natural radon, variable soil moisture, preventing moisture condensation, wide extremes of ambient temperature and wind-driven shifting of soil.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10167882
- Report Number(s):
- CONF-930257--7; ON: DE93015922
- Country of Publication:
- United States
- Language:
- English
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