Film badges, film badge dosimeters, are small portable devices for monitoring cumulative radiation dose due to ionizing radiation. Principle of operation is similar as for X-ray pictures. The badge consists of two parts: photographic film, and a holder. The film is contained inside a badge. The piece of photographic film that is the sensitive material and it must be removed monthly and developed. The more radiation exposure, the more blackening of the film. The blackening of the film is linear to the dose, and doses up to about 10 Gy can be measured.
Advantages and Disadvantages of Film Dosimeters
Advantages of Film Dosimeters
- A film badge as a personnel monitoring device are very simple and therefore they are not expensive.
- A film badge provides a permanent record.
- Film badge dosimeters are very reliable.
- A film badge is used to measure and record radiation exposure due to gamma rays, X-rays and beta particles.
Disadvantages of Film Dosimeters
- Film dosimeters usually cannot be read on site instead of they have to be sent away for developing.
- Film dosimeters are for one-time use only, they cannot be reused.
- Exposures of less than 0.2 mSv (20 millirem) of gamma radiation cannot be accurately measured.