Here's how it works:
1. Exposure: When the film badge is worn by an individual, the film inside is exposed to ionizing radiation (like X-rays, gamma rays, or beta particles).
2. Development: After a specified period (usually a week or a month), the film badge is returned to a laboratory for processing.
3. Analysis: The developed film is analyzed using a densitometer, which measures the darkness of the film. The darkness is directly proportional to the amount of radiation received.
4. Dose Calculation: Based on the density measurements and the type of radiation involved, the laboratory calculates the individual's radiation dose in units like millirems (mrem) or millisieverts (mSv).
Uses of film badges:
* Monitoring radiation workers: Film badges are commonly used by individuals working in environments where they are exposed to ionizing radiation, such as:
* Hospitals (radiology, nuclear medicine)
* Nuclear power plants
* Research laboratories
* Industrial settings (e.g., welding)
* Assessing radiation exposure: Film badges are used to determine the total amount of radiation exposure received by an individual over a specific time period, helping to ensure their safety and compliance with radiation safety regulations.
* Investigating radiation incidents: Film badges can be used to determine the source and level of exposure in case of a radiation incident or accident.
Advantages of film badges:
* Passive: They don't require external power or charging.
* Convenient: They are small and easy to wear.
* Affordable: They are relatively inexpensive compared to other types of dosimeters.
* Historical records: The developed film provides a permanent record of radiation exposure.
Disadvantages of film badges:
* Limited sensitivity: Film badges are not as sensitive as some other dosimeters, especially for low doses of radiation.
* Time lag: It takes time to develop and analyze the film, so the results are not available immediately.
* Limited range: They have a limited range of radiation energies that they can detect effectively.
Note: Film badges are being gradually replaced by other types of personal dosimeters, such as thermoluminescent dosimeters (TLDs) and electronic personal dosimeters (EPDs), which offer advantages like real-time readings and higher sensitivity. However, film badges remain a useful and affordable tool for monitoring radiation exposure in many situations.