Thermoluminescent dosimeters are passive detectors. After irradiation, a controlled heating cycle releases stored energy as light. The measured signal is used to estimate dose through a calibrated readout process. This makes the element, holder, reader, annealing procedure and calibration method parts of one dosimetry system.
1. Define the monitoring objective
Start by identifying the quantity and use case. Personal whole-body monitoring, extremity monitoring, workplace monitoring and environmental monitoring are not interchangeable. IEC 62387:2020 distinguishes quantities such as Hp(10), Hp(3), Hp(0.07), H*(10), H'(3) and H'(0.07) for photon and beta radiation monitoring systems.
2. Match the element to the radiation field
LiF:Mg,Ti
LiF:Mg,Ti is a well-established thermoluminescent material. It is widely used where a robust, familiar material and established laboratory procedures are important.
LiF:Mg,Cu,P
LiF:Mg,Cu,P is valued for high sensitivity and near tissue equivalence. Its response characteristics and heat-treatment requirements still need to be validated with the intended reader and annealing process.
6Li-enriched LiF
Where neutron response is required, lithium isotope composition matters. A dedicated neutron dosimetry design should be evaluated as a complete system. ISO 21909-1:2021 describes performance and test requirements for passive neutron personal dosimetry systems.
3. Evaluate the dose and energy ranges
Ask the supplier for the applicable dose range, element dimensions, batch information and available technical data. Energy dependence is important: different LiF materials can show different responses as photon energy changes. For a new application, laboratory irradiation tests should cover the relevant radiation qualities and dose levels.
4. Confirm reader and process compatibility
- Confirm whether the element format fits the reader tray, holder and handling workflow.
- Validate annealing, preheat and readout parameters before routine use.
- Measure background signal and repeatability using a representative sample from each batch.
- Check whether fading during the intended monitoring period is acceptable.
- Verify calibration traceability and document the acceptance criteria.
Practical recommendation: do not select a TLD element solely because it has higher nominal sensitivity. Choose the element that performs consistently within your complete, validated dosimetry system.
References
- IEC 62387:2020, dosimetry systems with integrating passive detectors for photon and beta radiation.
- ISO 21909-1:2021, passive neutron dosimetry systems for personal dosimetry.
- IAEA Individual Monitoring, Practical Radiation Technical Manual No. 2.