What device measures radiation exposure?

A dosimeter is specifically designed to measure the amount of radiation exposure that an individual or object has encountered over a specified period. It typically contains materials that react to ionizing radiation in a way that allows for the quantification of exposure, providing valuable personal safety information, especially in environments where radiation is present. Dosimeters can be in the form of passive devices, which are read after a period of wear to assess accumulated exposure, or active devices that give real-time readings.

While a radiometer also measures radiation, it is more commonly used to evaluate the intensity of radiation fields rather than tracking personal exposure over time. A Geiger counter detects and measures radiation but is primarily used for surveying radiation levels in an area rather than quantifying dose received by individuals. A calorimeter measures heat and energy transfer and is not related to radiation measurement.

Thus, the dosimeter stands out as the most appropriate choice for measuring personal radiation exposure.