Personnel monitoring devices are designed to measure the accumulated external exposure or dose that a person receives over some time interval. These devices are integrating, unlike dose rate meters or surveying instruments, which give an instantaneous readout.

General Principles of Monitoring Devices

• These devices must be compact and light enough to be worn at all times during working hours.
  

• They also must be inexpensive since so many are used at an institution and they are changed every month.

General Characteristics of Personnel Monitors

• Should be reliable and accurate  
  

• Should be sensitive to the type of radiation being monitored
  

• Should be inexpensive, portable, and easy to understand its operation