Final answer:
A film badge is the personnel radiation monitoring device with an accuracy of about plus/minus 25%. It is less sensitive to low levels of radiation and less reliable compared to crystal-based systems or electronic personal dosimeters.
Step-by-step explanation:
The personnel radiation monitoring device that has an accuracy of about plus/minus 25% is a film badge. Film badges contain photographic film, which when exposed to ionizing radiation causes fogging on the film in proportion to the amount of radiation exposure encountered. They are simple to use, indicating a person's exposure to radiation upon development and comparison with standards. However, they have limited sensitivity to low levels of radiation and are less reliable when compared to other devices that use crystals, such as Thermoluminescent Dosimeters (TLDs) or modern electronic personal dosimeters which measure the discharge levels of a rechargeable internal capacitor to determine the amount of exposure to ionizing radiation.