What device is primarily used for measuring radiation dose over time?

A dosimeter is a device specifically designed to measure and record the exposure to ionizing radiation over a period of time. It is often worn by individuals who work in environments where they may be exposed to radiation, such as medical professionals in radiology or nuclear facility workers. Dosimeters provide a cumulative radiation dose reading, allowing for assessment of long-term exposure to radiation, which is essential for ensuring safety and health compliance in radiation-sensitive occupations.

In contrast, while other devices like Geiger counters and scintillation counters are excellent for detecting radiation levels at a specific moment, they do not record cumulative exposure over time in a manner comparable to dosimeters. Survey meters are also used for evaluating radiation levels but are typically employed for immediate measurements rather than ongoing exposure assessments. Hence, the dosimeter uniquely fulfills the requirement for monitoring radiation dose over time, making it the correct choice for measuring cumulative radiation exposure.