Which device is essential for monitoring the radiation dose received by personnel?

The dosimeter is the essential device for monitoring the radiation dose received by personnel because it is specifically designed to measure and record the amount of ionizing radiation exposure over time. Personnel working in environments where they might be exposed to radiation, such as healthcare settings or nuclear facilities, are required to wear dosimeters to ensure that their exposure stays within safe and regulated limits.

Dosimeters can be passive, such as film badges or thermoluminescent dosimeters, which accumulate exposure over time and are analyzed later, or active, such as electronic dosimeters that provide immediate feedback. This monitoring is crucial for maintaining safety standards and protecting the health and well-being of workers by ensuring that any radiation exposure is tracked and managed appropriately.

Other devices listed, such as a control panel, thermometer, or X-ray machine, do not serve the primary function of measuring radiation dose for personnel safety. The control panel manages the operation of radiological equipment, the thermometer measures temperature, and the X-ray machine generates radiation for imaging, but none provide direct monitoring of radiation exposure for individuals.