Radiation Monitoring Badges

When Radiation Monitoring Badges Are Required

You must wear radiation monitoring badges if:

  • You operate x-ray machines (including x-ray diffraction equipment, x-ray fluorescence equipment and cabinet x-ray systems)
  • You are a Declared Pregnant Worker working in a lab where x-ray and gamma emitters or energetic beta emitters are used
  • If you use radioactive materials under the following conditions:


    Monitoring Is Required If:

    For Open Radioactive Sources

    P-32 (and other beta emitters
    with energies > 250 keV)

    Used in amounts of 5 mCi or more for extended operations. Not required for simple aliquoting from a stock vial

    I-125 and Cd-109 (and other
    x-ray or gamma emitters with energies < 100 keV)

    Used in amounts of 1 mCi or more for extended operations. Not required for simple aliquoting from a stock vial

    Cr-51, Co-57, Fe-59 and Zn-65
    (and other x-ray or gamma emitters with energies > 100 keV)

    Used in amounts of 0.5 mCi or more for extended operations. Not required for simple aliquoting from a stock vial

    For Contained  (Non-Dispersible Sources)

    Co-60, Cs-137 and Ra-226
    (and other energetic beta/gamma emitters)

    Used in amounts > 0.1 mCi

    Optional Monitoring

    (When badging isn’t required but you’d like to be badged)

    If you work in a laboratory in which gamma emitters or energetic beta emitters are used, you may request radiation monitoring badge service, even if you do not meet the criteria for required monitoring. Use the Badging Service Request form on the Resources sidebar to make your request or email the RSO. We do not provide monitoring for persons working in laboratories in which only alpha emitters or low energy beta emitters (< 250 keV) are used, since our radiation monitoring badges cannot detect these radiations.

    >Return to Top

    Using & Wearing Radiation Monitoring Badges

    How the Monitoring Badges Work

    The body badge and the ring badge each contains a radiation-sensitive lithium fluoride crystal. When atoms in the crystal are exposed to radiation, electrons are trapped in an excited state until the crystal is heated to a very high temperature. The released energy of excitation, which is given off as visible light, is measured to determine radiation dose. This phenomenon is called thermoluminescence and dosimeters that use this principle are often referred to as TLDs (thermoluminescent dosimeters).

    The minimum reported dose for the body badge is 10 millirems for x-rays and gamma rays. The minimum detectable dose for the ring badge is 20 millirems for x-rays and gamma rays.

    Where to Wear Monitoring Badges

    • Wear your body badge on the part of the body between your neck and waist that is closest to the source of radiation.
    • The body badge contains a series of filters designed so that the energy and type of radiation can be determined. In order for the radiation type and energy to be determined, the dosimeter must be worn so that the front of the badge faces towards the source of radiation.


      Body badge clipped to the front of the lab coat with the name tag facing out

      The nametag on the badge is facing away from the body.

    • Wear your ring badge so that the label is facing out from the side of the hand most likely to receive a radiation exposure.
    • If you are wearing gloves, wear the ring inside your glove so the ring does not become contaminated. Be careful not to leave the badge inside the glove when you pull the glove off.

    Guidelines for Monitoring Badge Use

    • Never share your badges or wear another person’s badges. If you discover that your badges are missing or damaged, notify EHS promptly. EHS can usually provide you with replacement badges within a couple of hours.
    • Do not intentionally expose badges to radiation. Intentional tampering with badges is a very serious legal matter.
    • No matter how curious you are, do not wear your badges when you receive a medical x-ray or other medical radiation treatment. Your badges are intended to document your occupational dose, not your medical dose. 

    Lost or Damaged Monitoring Badges

    If you lose, damage, or contaminate your badge, call EHS immediately for a replacement. EHS can generally provide you with a replacement badge within a few hours of your request. Do not borrow anyone else's badge.

    Badge Exchange and Processing

    Badges are exchanged quarterly. You should expect to receive your new badges a day or two before the start of each calendar quarter. The badges are either mailed directly to you or delivered to the badge contact person in your lab. Mail your old badges from the quarter just ended back to EHS or return them to the lab’s badge contact.

    Charges for Lost or Late Badges

    Your lab will be charged $5 for each ring badge and $14 for each body badge that is not returned within 90 days following the end of the quarter in which the badge was worn.

    >Return to Top

    Dose Reports and How to Read Them

    Reviewing Dose Reports

    After you return your monitoring badges at the end of each quarter, the badges are sent out to Mirion Technologies for processing. EHS receives and reviews the dose reports several weeks after the end of a monitoring period. EHS has established investigational levels at doses that are 10% or less of the federal and state dose limits. If a dose is reported that exceeds the investigational level, EHS will contact you to determine whether the reported dose is likely to be accurate and to investigate the causes of the dose in an effort to minimize dose in the future.

    Your Online Account with Mirion

    Mirion Technologies provides you with the capability to create an online account so that you can be notified when your dose results are available online and so that you can view your dose report online. Mirion calls this feature MDR (My Dose Review). When you receive your badges, EHS will provide you with instructions for setting up this account. You can also request a summary of your monitoring badge results by calling EHS.  It is not required that you view your dose report; however, this is the only way that you will routinely be notified about your dose results. The RSO always reviews the quarterly dose reports and will follow up with you if the RSO notes any doses of concern.

    Deep & Shallow Doses

    In the case of body badges, doses are reported as deep or shallow or as doses to the lens of the eye. Deep dose is due to penetrating radiations such as gamma rays or higher energy x-rays. Deep doses are applied against the whole body dose limit. Shallow dose is due to less penetrating radiations such as beta radiation and low energy x-rays. Shallow doses are applied against the skin dose limit. Dose to the lens of the eyes is due to an intermediate range of radiations and energies and is applied against the lens of the eye dose limit. In the case of ring badges, dose is only reported as shallow dose and is applied against the extremities dose limit.

    Minimum Detectable Doses

    Doses are reported in millirems. The minimum reported dose for x-rays for body badges is 10 millirems for x-rays, and for ring badges is 20 millirems. If no dose is reported, the total dose received was less than the minimum reported dose.

    >Return to Top

    Exposure History

    Contact EHS for a copy of your radiation exposure history. EHS maintains radiation exposure records indefinitely. If you terminate employment with the University, EHS will provide your radiation exposure history to you or your new employer upon request. Requests for radiation exposure histories should be mailed to: EHS, 262 Alexander Street, Princeton, NJ 08540

    >Return to Top

    Radiation Use at Other Institutions

    Do not take Princeton monitoring badges to any other institution. Princeton University provides badges to you solely to measure the radiation dose you receive while working at Princeton University. If you perform radiation work at another institution, it is the responsibility of that institution to provide you with monitoring badges. However, Princeton University must still control the dose you receive while working at Princeton so that your total occupational dose does not exceed regulatory dose limits. If another institution issues you radiation monitoring badges, notify EHS. EHS will contact that institution and request copies of your dose records.

    >Return to Top



Colt Greer
Radiation Safety Officer

Chelsea McDonnell
Health and Safety Technician