ASNT Industrial Radiography Radiation Safety Practice Test

What distinguishes an ion chamber from film badges and thermoluminescent dosimeters (TLDs)?

1. Ion chambers are less accurate

2. Ion chambers cannot be easily transported

3. Ion chambers are direct reading instruments

4. Ion chambers are cheaper to manufacture

The correct answer is: Ion chambers are direct reading instruments

The distinguishing feature of ion chambers compared to film badges and thermoluminescent dosimeters (TLDs) is that ion chambers are direct reading instruments. This means they provide immediate readings of radiation exposure, allowing users to monitor radiation levels in real-time. This characteristic is especially useful in environments where rapid assessments are crucial for safety, such as during industrial radiography operations. In contrast, film badges and TLDs measure cumulative exposure over a period. They require processing to obtain the readings, which can result in delays in assessing exposure levels. While each dosimetry option has its unique applications, the immediate feedback offered by ion chambers sets them apart as a critical tool for monitoring radiation exposure in real-time situations.