What is a TLD dosimeter? Dosimetry is the process of measuring radiation. Multiple instruments are available that detect and measure the presence of radiation in a laboratory, handheld or worn, like a dosimeter badge or ring from RadiationSafety.com.  

When ionizing radiation loosens electrons, phosphor crystals in a dosimeter or dosimetry badge capture and store them. When those crystals are exposed to heat, they emit light as the electrons are released from the crystals, which illuminates a light on a dosimeter badge, band, or ring. That light is later measured and processed to provide a precise amount of radiation to which the dosimeter was exposed. When the dosimeter badge, band, or ring is worn over a period of time, anywhere from one to three months, the crystals can then be used to determine how much exposure the wearer has had over that period. This process is known as dosimetry.dosimeter badge OSL x-ray safety

A TLD dosimeter, or thermoluminescent dosimeter, is a passive radiation dosimeter that measures ionizing radiation. Ionizing radiation is caused by X-rays, gamma rays, beta particles, alpha particles, and other radioactive isotopes that carry enough energy to free electrons from their orbit around normally stable molecules. While this can cause damage to cells in living tissue, it also can be captured and measured in a well-designed environment, like in a dosimetry badge. In addition, ionizing radiation causes damage over time, so monitoring, limiting, and controlling how much a person is exposed to is essential. 

Invented by Professor Farringon Daniels of the University of Wisconsin-Madison in 1954, the TLD dosimeter requires heat to function. They are most useful for situations where information about radiation amounts must be precise but not immediately required. TLD dosimeters can measure accumulated dosages to monitor potential health impacts. 

A better alternative to TLD dosimeter badges is OSL XBG dosimeter badges.

Pros and Cons of TLD Dosimeters


  • TLD dosimeters measure a large range of doses over a period of time.
  • TLD dosimeters are typically the same price or even higher than OSL technology.


  • TLD dosimeters require heat to function.
  • Only one dose can be read at a time.
  • Once the dose is read, it resets the dosimeter.
  • One of the largest manufacturers of TLD badges and readers quit servicing their machines.
  • TLD dosimeter badges tend to have a higher rate of “fade” than OSL badges.

RadationSafety.com provides radiation badges and rings that are affordable and unobtrusive. They utilize optically stimulated luminescence OSL technology, a more advanced technology than TLD dosimeters. OSL dosimeter badges are the industry standard used by the government, hospitals, labs, and companies worldwide. An OSL dosimeter works similarly to a TLD dosimeter, but an OSL dosimeter only requires optical stimulation, whereas a TLD dosimeter requires heat to function. These small and discrete radiation badges can be worn on your lapel and are designed to detect X-rays, gamma radiation, and beta particles, with neutron monitoring available for an additional fee.

Source: ​​https://www.radiation-dosimetry.org/what-is-thermoluminescent-dosimeter-tld-definition/ 


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