What is the purpose of a dosimeter?

A dosimeter is a device that measures an individual's exposure to ionizing radiation over a specified period. This is crucial in radiation safety practices, especially for healthcare workers and others working in environments where they may be exposed to radiation. The information obtained from a dosimeter helps to ensure that exposure levels remain within safe limits, allowing for appropriate safety measures to be taken if necessary.

The other choices do not align with the primary function of a dosimeter. While detecting environmental radiation levels is important in broader safety practices, this task is typically associated with other types of monitoring equipment rather than personal dosimetry. Medical treatment is unrelated to the function of a dosimeter, as it is not a therapeutic tool but rather a monitoring device. Additionally, calculating the half-life of isotopes pertains to nuclear physics and radiochemistry rather than individual radiation exposure measurement, further distinguishing dosimeters from these functions.