A thermoluminescent dosimeter, abbreviated as TLD, is a passive radiation dosimeter, that measures ionizing radiation exposure by measuring the intensity of visible light emitted from a sensitive crystal in the detector when the crystal is heated. The intensity of light emitted is measure by TLD reader and it is dependent upon the radiation exposure. Thermoluminescent dosimeters was invented in 1954 by Professor Farrington Daniels of the University of Wisconsin-Madison. TLD dosimeters are applicable to situations where real-time information is not needed, but precise accumulated dose monitoring records are desired for comparison to field measurements or for assessing the potential for long term health effects. In dosimetry, both the quartz fiber and film badge types are being superseded by TLDs and EPDs (Electronic Personal Dosimeter).
Advantages and Disadvantages of TLDs
Advantages of TLDs
- TLDs are able to measure a greater range of doses in comparison with film badges.
- Doses from TLDs may be easily obtained.
- TLDs can be read on site instead of being sent away for developing.
- TLDs are easily reusable.
Disadvantages of TLDs
- Each dose cannot be read out more than once.
- The readout process effectively “zeroes” the TLD.