Radiation Monitoring Devices

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  • Occupational Safety & Risk Management
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  • Radiation survey meters are required in most labs working with radiation. There are several types of survey meters, and care must be taken to select one sensitive to the radiation in use. One common isotope that requires special consideration is Tritium (H-3), which emits a low-energy beta that is not detectable by most handheld survey meters.

    Some common types of radiation monitoring devices include:

    • Geiger Muller (GM)
      • Best for: Beta Sources (e.g. P-32, S-35, Tc-99)
    • Ionization Chamber
      • Best for: Medium to high dose rate Gamma/X-Ray measurement
    • Sodium Iodide (NaI)
      • Best for: Gamma sources (e.g. Na-22, Cs-137, I-125)
    • Liquid Scintillation Counter (LSC)/Gamma Counter (GC)
      • Best for: Tritium contamination detection, radiation quantification

    Choosing a meter

    Meters are typically sold in two parts, a meter and a detector (or probe). Many meters and detectors are interchangeable. For example, one of the most popular meters is the Ludlum Model 3. The Model 3 can be equipped with different detectors based on the needs of the lab, such as the Model 44-9 pancake GM detector which is good for beta sources or the Model 44-3 NaI detector for gamma sources.

    Radiation Safety - Ludlum Model 3

    Ludlum Model 3

    Radiation Safety - 44-9 GM Detector

    44-9 GM Detector

    Radiation Safety - 44-3 NaI Detector

    44-3 NaI Detector

    Some common meter vendors/manufacturers include:

    If ordering a new meter, please contact the Radiation Safety Office. Certain meters cannot be calibrated on campus and would need to be serviced by an outside vendor. Additionally, the new meter will need to added to the EH&S database.

    Radiation meters are required to be calibrated:

    • Every nine months for non-human use
    • Every six months for human use

    EH&S offers calibrations and minor repairs for most meters. Every meter should be labeled with a calibration sticker which will state the due date of the next calibration.

    Radiation Safety

    Meters are collected from labs as their due date approaches. Please do not use a meter if it is outside of the calibration date. If your meter has become out of calibration, notify the Radiation Safety Office.