What is a Dosimeter?
A Dosimeter measures a person’s exposure to radiation in occupational settings, and is sometimes called a “badge” or “X-ray badge”. There are a number of different kinds of dosimeters. The types we use are called thermoluminescent dosimeters (TLDs), which contain filters and crystals to determine the type and amount of radiation received (X-ray, gamma, beta, or neutron).
As the dosimeter is exposed to radiation, energy is deposited in the crystals within the dosimeter. During processing, the crystals are heated and energy is released in the form of light and a glow curve is captured. The data is passed through an algorithm which is used to determine the type of received radiation and calculate the worker’s occupational exposure.
Why is Dosimetry important?
Employers utilizing sources of radiation in their business can only legally do so if they are in possession of a license permitting them to safely operate their sources. The licensee must control and monitor the occupational dose to individual employees. Occupational dose means the dose received by an individual in the course of employment in which the individual’s assigned duties involve exposure to radiation or to radioactive material from licensed and unlicensed sources of radiation. The Nuclear Regulatory Commission (NRC) states in the Code of Federal Regulations (10CFR20):
§ 20.1101 Radiation protection programs.
(a) Each licensee shall develop, document, and implement a radiation protection program commensurate with the scope and extent of licensed activities and sufficient to ensure compliance with the provisions of this part. (See § 20.2102 for recordkeeping requirements relating to these programs.)
(b) The licensee shall use, to the extent practical, procedures and engineering controls based upon sound radiation protection principles to achieve occupational doses and doses to members of the public that are as low as is reasonably achievable (ALARA).