What does a dosimeter measure?

A dosimeter measures the amount of ionizing radiation exposure that an individual has received over a certain period. The key aspect of a dosimeter's function is that it captures and stores the accumulated dose of radiation, which can be read later to indicate how much radiation the wearer has been exposed to since the last time it was read or reset.

The concept that a dosimeter registers the dose received from the last time it was charged aligns with its primary purpose of monitoring and recording personal radiation exposure for safety evaluations and regulatory compliance. This cumulative measurement helps ensure that personnel are not exceeding prescribed radiation limits during their work, thus maintaining safety in environments where radiation is present.

The other choices pertain to measurements that may be relevant in specific contexts but do not accurately reflect what a dosimeter directly measures. For example, dose rate is a measure of exposure over time rather than total accumulated exposure. Lifetime exposure would require a different type of record-keeping and is generally not the direct function of a dosimeter. Similarly, weekly exposure indicates a periodic assessment, which is not how dosimeters function as they provide a total measure from the last reading.