Personnel neutron dosimetry using electrochemically etched CR-39 foils
This report describes a personnel neutron dosimetry system based on the electrochemical etching of CR-39 plastic at elevated temperatures. The CR-39 dosimetry system has several advantages: the doses obtained using this system are more accurate than those from other dosimetry systems, especially when varied neutron spectra are encountered; CR-39 does not have the severe energy dependence that exists with albedo neutron dosimeters, nor does it have the fading and reading problems encountered with NTA film. The energy response of CR-39 to neutrons is fairly flat from about 150 keV to 4.0 MeV, but drops by about 60% in the 13 to 16 MeV range. The sensitivity of the dosimetry system is about 4.5 tracks/mrem, with a background equivalent to about 8 mrem for new CR-39 foils. The limit of sensitivity is approximately 10 mrem. We describe our three-stage electrochemical etch procedure that can be used to process large numbers of CR-39 dosimeters quickly. The stages in the etching procedure improve the track quality and the precision of the track counting, and also reduce the background counts caused by imperfections, scratches, or dirt on the foils. We are investigating the use of a track-size distribution method to determine information on the incident neutron energy or spectrum. 6 refs., 17 figs., 2 tabs.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5550200
- Report Number(s):
- UCRL-53833; ON: DE88005099
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
61 RADIATION PROTECTION AND DOSIMETRY
655003 -- Medical Physics-- Dosimetry
DETECTION
DIELECTRIC TRACK DETECTORS
DOSIMETRY
EVALUATION
MEASURING INSTRUMENTS
NEUTRON DOSIMETRY
OPTIMIZATION
PARTICLE TRACKS
PERSONNEL DOSIMETRY
RADIATION DETECTORS
RADIATION PROTECTION
RESOLUTION
SENSITIVITY