A dosimeter is a device used to measure an individual's exposure to ionizing radiation over time. It is commonly used in environments where radiation is present, such as hospitals, nuclear power plants, and research facilities. Dosimeters help ensure that workers are not exposed to harmful levels of radiation, providing important safety data. There are various types of dosimeters, including film badges, thermoluminescent dosimeters (TLDs), and electronic personal dosimeters (EPDs). Each type operates differently but serves the same purpose: to monitor radiation exposure. Regular monitoring helps protect health and safety in radiation-related occupations.