Combination TLD/TED dose assessment
During the early 1980s, an appraisal of dosimetry programs at US Department of Energy (DOE) facilities identified a significant weakness in dose assessment in fast neutron environments. Basing neutron dose equivalent on thermoluminescence dosimeters (TLDS) was not entirely satisfactory for environments that had not been well characterized. In most operational situations, the dosimeters overrespond to neutrons, and this overresponse could be further exaggerated with changes in the neutron quality factor (Q). Because TLDs are energy dependent with an excellent response to thermal and low-energy neutrons but a weak response to fast neutrons, calibrating the dosimetry system to account for mixed and moderated neutron energy fields is a difficult and seldom satisfactory exercise. To increase the detection of fast neutrons and help improve the accuracy of dose equivalent determinations, a combination dosimeter was developed using TLDs to detect thermal and low-energy neutrons and a track-etch detector (TED) to detect fast neutrons. By combining the albedo energy response function of the TLDs with the track detector elements, the dosimeter can nearly match the fluence-to-dose equivalent conversion curve. The polymer CR-39 has neutron detection characteristics superior to other materials tested. The CR-39 track detector is beta and gamma insensitive and does not require backscatter (albedo) from the body to detect the exposure. As part of DOE`s Personnel Neutron and Upgrade Program, we have been developing a R-39 track detector over the past decade to address detection and measurement of fast neutrons. Using CR-39 TEDs in combination with TLDs will now allow us to detect the wide spectrum of occupational neutron energies and assign dose equivalents much more confidently.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 10134927
- Report Number(s):
- PNL-SA-19375; CONF-9211124-7; ON: DE93008257
- Resource Relation:
- Conference: Harshaw/quality systems (QS) 1992 thermoluminescent dosimetry (TLD) user symposium,San Antonio, TX (United States),9-13 Nov 1992; Other Information: PBD: Nov 1992
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
61 RADIATION PROTECTION AND DOSIMETRY
36 MATERIALS SCIENCE
FAST NEUTRONS
NEUTRON DETECTION
NEUTRON DETECTORS
RESEARCH PROGRAMS
RADIATION DOSES
THERMOLUMINESCENT DOSEMETERS
NEUTRON DOSIMETRY
DOSE EQUIVALENTS
POLYMERS
DIELECTRIC TRACK DETECTORS
ETCHING
440102
560101
360606
RADIATION DOSEMETERS
DOSIMETRY AND MONITORING
PHYSICAL PROPERTIES