Which type of personnel radiation monitor can provide an immediate reading of radiation levels?

The ionization chamber is a type of personnel radiation monitor that provides immediate readings of radiation levels. This device functions by measuring the electrical charge produced when ionizing radiation passes through a gas contained within the chamber. As radiation interacts with the gas molecules, it results in ionization, creating positive ions and free electrons. This generates a measurable current that correlates with the radiation intensity, allowing for real-time monitoring of exposure.

In contrast, other options like the film badge, thermoluminescent dosimeter, and optically stimulated luminescent dosimeter do not provide immediate readings. Film badges require chemical processing before the exposure can be assessed, thermoluminescent dosimeters must be heated to release stored energy before readings can be taken, and optically stimulated luminescent dosimeters rely on a specific light stimulation process for reading. These properties make the ionization chamber particularly valuable in situations where instant radiation level assessments are necessary for monitoring safety in environments with potential radiation exposure.