Neutron Contribution to CaF2:Mn Thermoluminescent Dosimeter Response in Mixed (n/y) Field Environments

Abstract

Thermoluminescent dosimeters (TLDs), particularly CaF 2 :Mn, are often used as photon dosimeters in mixed (n/γ) field environments. In these mixed field environments, it is desirable to separate the photon response of a dosimeter from the neutron response. For passive dosimeters that measure an integral response, such as TLDs, the separation of the two components must be performed by post-experiment analysis because the TLD reading system cannot distinguish between photon and neutron produced response. Using a model of an aluminum-equilibrated TLD-400 chip, a systematic effort has been made to analytically determine the various components that contribute to the neutron response of a TLD reading. The calculations were performed for five measured reactor neutron spectra and one theoretical thermal neutron spectrum. The five measured reactor spectra all have dosimetry quality experimental values for aluminum-equilibrated TLD-400 chips. Calculations were used to determined the percentage of the total TLD response produced by neutron interactions in the TLD and aluminum equilibrator. These calculations will aid the Sandia National LaboratoriesRadiation Metrology Laboratory (SNL-RML) in the interpretation of the uncertainty for TLD dosimetry measurements in the mixed field environments produced by SNL reactor facilities.4

Criticality Accident Alarm System Shielding Benchmark: Integral Experiment Request 498, Critical Engineering Decision 2 Report

“…A TLD is roughly accurate to 3% based on a paper for doses at the 0.36 mGy level (calculated as roughly the exposure over the measurement period) [24]. TLDs do not tend to suffer from neutron activation [25]. A report on Sandia Pulsed Reactor (SPR) III, a highly enriched uranium (HEU)-fueled burst assembly with similarities to Godiva IV, notes that activation near the TLD can interfere with the dose measurement [26].…”

Analysis and Recent Advances in Gamma Heating Measurements in MINERVE Facility by Using TLD and OSLD Techniques

“…Difficulties arise when the nuclear data are poorly known, which it is not the case for an application to OSLD measurements. This method has been studied in reference [22], by using aluminum surrounding material, and could be directly transposed to the first phase of measurements in MINERVE aluminum pillboxes.…”

Analysis and recent advances in gamma heating measurements in MINERVE facility by using TLD and OSLD techniques

“…This method has been studied in reference [20], by using aluminum surrounding material, and could be directly transposed to the first phase of measurements in MINERVE aluminium pillboxes.…”