Performance evolution of TLD-700H/600H dosimetry system at extended issue periods
Alexander A. Romanyukha, Matthew Grypp, F. Trompier, Alan Keith Thompson, Ronaldo Minniti, Jacque Debroas, Anthony S. Williams
Results of a comprehensive study of the TLD-700H/600H dosimetry system performance for an extended issue period are presented and discussed. It was concluded that the obtained results provide a technical justification to use the current dosimetry system at significantly larger extended issue periods (up to almost 600 days) compared to the current 95-day issue period used at the Naval Dosimetry Center (NDC). It was also found that extending (or reducing) the issue period has a statistically significant effect on the uncertainty of the dose equivalents measured with the dosimetry system. In order to accommodate use of various issue periods in the same dosimetry system the lower limit detection (LLD) linear model is proposed. A possible limitation of this model (no significant dose fading) is discussed. The factors responsible for both time independent and dependent LLD components are identified. The TLD residual signal and dosimetry system calibration are responsible for the time-independent LLD component; whereas the time-dependent LLD components are: dose fading, radiation background, and its standard deviation. Simple formulae for photon and neutron LLDs at variable dosimeter issue periods were proposed. As a result of the experimental study conducted, all LLD components were numerically evaluated for the four-element TLD-700H/600H dosimetry system at different issue periods. Implementation of these formulae in the dose algorithm may provide a more accurate LLD estimation for each reported dose equivalent at any technically justified dosimeter issue period.
, Grypp, M.
, Trompier, F.
, Thompson, A.
, Minniti, R.
, Debroas, J.
and Williams, A.
Performance evolution of TLD-700H/600H dosimetry system at extended issue periods, Radiation Protection Dosimetry, [online], https://doi.org/10.1016/J.radmeas.2017.12-0003
(Accessed December 5, 2022)