Personal dosimeters are portable devices worn by individuals to measure, record, and track the cumulative dose of ionizing radiation they receive over a specific period. In industries dealing with NORM, such as Mineral sand mining and oil and gas, these devices are essential for ensuring that workers stay within regulatory dose limits and for validating the effectiveness of radiation safety controls.
Different types of dosimeters are used depending on the radiation field (e.g., Gamma Radiation, Beta radiation) and the required monitoring frequency.
TLDs contain crystals (like lithium fluoride) that trap electrons when exposed to radiation. When heated in a laboratory, the crystals emit light proportional to the radiation dose received.
EPDs provide real-time dose and dose-rate readings via a digital display. They often include audible alarms that trigger when specific thresholds are reached.
Similar to TLDs but read using laser light. They are highly sensitive and can be re-read multiple times.
In NORM environments, dosimeters primarily track external exposure from Gamma Radiation. However, they are often used in conjunction with other monitoring techniques, such as:
The use of dosimeters is part of a broader Radiation Management Plan (RMP). Employers are required to: