Radiation Protection Dosimetry Advance Access originally published online on July 11, 2008
Radiation Protection Dosimetry 2008 131(3):279-286; doi:10.1093/rpd/ncn182
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Long-term fade study of the DT-702 LiF: Mg,Cu,P TLD
1 Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
2 US Naval Dosimetry Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA
* Corresponding author: delzer{at}tds.net
Received March 4, 2008, amended June 4, 2008, accepted June 10, 2008
LiF thermoluminescent dosemeters (TLDs) are used by the US Navy to record radiation exposure of personnel. The Model DT-648 LiF:Mg,Ti TLD has been replaced by a new Model DT-702 LiF:Mg,Cu,P TLD. The DT-648 was used for many years and has undergone extensive testing to identify its pre- and post-irradiation fade operating characteristics. Studies have shown that the addition of copper increases the thermoluminesence sensitivity of the TLD for improved low-level radiation monitoring. This study evaluates various fading characteristics of the new copper-doped dosemeter using current equipment for processing of TLDs and calibrating to a National Institute of Standards and Technology standard source. The 57-week study took place at the Naval Dosimetry Center, Bethesda, MD, USA. TLDs were stored for various lengths of time before and after being exposed to a National Institute of Standards and Technology calibrated radiation sources. TLDs were then processed using current US Navy instructions and the resulting dose compared with the calibrated exposure. Both loss of signal and loss of sensitivity were evaluated. The results of this study have shown that the DT-702 TLD has no statistically significant change in sensitivity or change in signal with up to 57 weeks of pre- or post-irradiation time. The results of this study will increase the accuracy of exposure record keeping for the Navy and will allow longer issue periods. This will increase flexibility with international and domestic shipping procedures, as well as reduce workload requirements for dosimetry processing.
J. A. Delzer is a military service member (USA). This work was prepared as part of my official duties. Title 17 U.S.C. 105 provides that ‘Copyright protection under this title is not available for any work of the US Government’. Title 17 U.S.C. 101 defines a US Government work as a work prepared by a military service member or employee of the US Government as part of that person's official duties.