Hanford environmental CaF2:Mn thermoluminescent dosimeter
The TLD-400 chips combined with the Pb-Ta field capsule provide a sensitive method of measuring penetrating ambient radiation in the environment. The method is best used for field deployments of about 1 month or less to minimize problems associated with fading. A correction factor of about 10% is necessary for the readings obtained for a 28-day field deployment and a 1-day wait before readout. Integration of reader output from 150/sup 0/C to 280/sup 0/C provides a good signal-to-noise ratio for TLD-400 chips exposed to 5 mR for the reader and planchet described herein. Visual inspection of the glow curves is recommended during startup of any new program or following any major instrument repair. The glow curves can be easily drawn with an X-Y recorder. Because of the large energy dependence of bare TLD-400 chips, an energy-flattening filter is necessary to allow a direct conversion from a reference exposure to observed field exposures. The field capsule used, consisting of 10 mil of tantalum and 2 mil of lead, provides an approximate uniform energy response above 70 keV. Below 70 keV, the response decreases rapidly because of the shielding. Experiments conducted have not shown the TLD-400 chips to be sensitive to the extremes of summer temperature (approximately 50/sup 0/C) occasionally encountered at Hanford. Although the field dosimeter exhibits a directional dependence, this is of primary concern during calibration, in which the axis of the dosimeter should be normal to the photon beam. The procedures used to interpret the TLD chip reader output in terms of dose are fully described in the text.
- Research Organization:
- Battelle Pacific Northwest Labs., Richland, Wash. (USA)
- DOE Contract Number:
- EY-76-C-06-1830
- OSTI ID:
- 7029489
- Report Number(s):
- PNL-2489
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CALIBRATION
CORRECTIONS
DATA ANALYSIS
DOSEMETERS
DOSIMETRY
ENERGY DEPENDENCE
ENVIRONMENT
FILTERS
FLUORIDES
FLUORINE COMPOUNDS
GLOW CURVE
HALIDES
HALOGEN COMPOUNDS
HAPO
HEAT TREATMENTS
LUMINESCENT DOSEMETERS
MEASURING INSTRUMENTS
MONITORING
NATIONAL ORGANIZATIONS
PERFORMANCE
RADIATION MONITORING
READOUT SYSTEMS
THERMOLUMINESCENT DOSEMETERS
THERMOLUMINESCENT DOSIMETRY
US AEC
US ERDA
US ORGANIZATIONS