8 Must-Know Facts About Control Dosimeters

Control dosimeters play an important role in calculating occupational radiation exposure, but they are often overlooked or used incorrectly. Our team at RDC compiled a breakdown of everything you need to know about control dosimeters so you can confidently manage your radiation dosimetry equipment.

Without further ado, here are eight things you should know about control dosimeters.

What Is a Control Dosimeter?

A control dosimeter is a dosimetry badge that is fundamentally the same as the radiation badge used to protect radiation workers. However, control dosimeters specifically measure external radiation exposure from ambient background radiation sources (while badges worn by staff measure occupational exposure and ambient background radiation).

The most common non-occupational sources of radiation exposure are:

• Cosmic radiation: natural background radiation originating in outer space and made up of penetrating ionizing radiation (particulate and electromagnetic)
• Irradiation that occurs during badge shipments and/or badge returns
• Natural radioactive material found in building materials and soil at a worksite

Why Do I Need a Control Dosimeter?

A control dosimeter plays an integral role in providing an accurate measure of occupational dose. Occupational dose is the amount of ionizing radiation (including X-ray, gamma, beta, or neutron radiation) exposure received by workers during their employment.

Control badges measure the background radiation dose received during shipment (either to your organization or back to your dosimetry provider) and storage throughout your wear period. To obtain occupational dose, the measurement recorded on the control dosimeter is subtracted from the individual doses recorded on each badge in the group.

The difference between the two measurements equates to the occupational dose of the radiation worker. Keeping an accurate measure of occupational radiation ensures the number is within the limit allowed by applicable regulations.

How Do I Get a Control Dosimeter?

A control dosimeter should be included in each regular badge shipment as part of your agreement with your service provider. Dosimeter badges from RDC include TLD (with or without a neutron monitoring option), OSL, or digital dosimeters – with extremity badges in both ring dosimeter and wrist options. RDC also offers multiple monitoring option types, such as personnel whole-body monitoring, area monitoring, fetal monitoring, and more.

If you are unsure what type of whole body dosimeter badge is best for your company, you can explore our complete range of solutions here. You can also complete our contact form and we'll be happy to connect with you and help evaluate your organization’s needs.

How to Store a Control Badge Dosimeter

Proper storage of the control dosimeter is essential for accurate reporting and compliance. Your company's radiation safety program and radiation safety officer should provide proper storage details. The most important element is that the control badge is stored away from the radiation source at your facility and in a location that represents the background radiation for your workplace.

Storing radiation dosimeters together with the control dosimeter provides the best estimate of the ambient background radiation onsite.

Dosimeter storage boards, also called " badge boards," can provide a standardized storage location for all workers to place their dosimeters when they're not in use. Placing these storage boards at your facility's entry or exit is a reminder for workers to put on their dosimeters when entering and to place them on the board before exiting the facility.

If you don't have a dosimeter storage board, the next best location is an area representative of the background radiation exposure that the control dosimeter is monitoring. In most cases, a break room or reception area is an appropriate storage location.

You don't need a custom badge board to store dosimeter badges. Below, we're sharing a few ideas for dosimeter badge storage based on feedback from our customers and ideas from our team.

8 Easy Dosimetry Badge Storage Options

#1: Labeled Drawer System

Use a small, sectioned drawer unit (like those for office supplies or jewelry) and label each section with staff names or roles for easy organization. A labeled drawer system is ideal for keeping dosimeters dust-free and secure.

#2: Pegboards with Clips

Mount a pegboard with labeled hooks or clips for each dosimeter. This method provides flexibility while keeping badges visible and organized. You can even customize the pegboards with colors or designs that match your office decor.

#3: Wall-Mounted File Organizer

Use a wall-mounted file organizer or mail sorter with individual slots for each staff member. Label each slot for quick access or clip the badges to each file – this option keeps dosimeters off counters but still within reach and easy to grab.

#4: Magnetic Strips or Boards

You can use a magnetic board to hang dosimeters with metallic clips in an out-of-the-way location away from radiation sources.

#5: Countertop Organizer

Use a compact countertop organizer for an easily accessible option with a minimalistic aesthetic. Organizers meant for glasses or keys work great and will hold dosimeters upright in individual compartments.

#6: Hanging Pockets

We've seen this one work nicely for larger teams or as a mobile storage solution. Simply utilize hanging pocket organizers (often used for shoes or office supplies).

#7 Artistic or Thematic Displays

This could be a fun team-building activity: gather your staff to build a custom display.

• Veterinary clinics: Use animal-shaped hooks, a wooden cutout of a bone or paw print, or dog leashes.
• Dental offices: Use tooth-shaped pegs or organizers.
• Hospitals: Use a simple, professional acrylic cutout of a first aid sign or stainless-steel rack personalized with your organization's logo.

#8: Individual Lanyards, Dog Leashes, or ID Clips

Assign each staff member a lanyard or clip specifically for their dosimeter and encourage them to wear it when not in storage, then use a designated hook or area for storing lanyards when not in use.

What to Avoid When Storing a Control Badge Dosimeter

It's essential to follow best practices for storing your control dosimeter (and personnel dosimeters!). Remember to keep these "don'ts" in mind so you can get the most accurate dose reports.

• Don't store radiation dosimeters (or control dosimeters, for that matter) in desks, offices, control rooms, outside X-ray rooms, in cars, at home, or on a lead apron.
• Never store the control dosimeter in a lead box or safe because it will underestimate the background radiation.
• Don't issue a control dosimeter to a radiation worker or use it as an area monitor. If your office has a badge coordinator, they can share where your badge should be stored.

For more information about wearing and managing X-ray badges, please check out our blog on Best Practices for Wearing a Radiation Dosimeter Badge.

Frequently Asked Questions

How Many Control Dosimeters Do I Need?

If you plan on storing all personnel radiation badges in the same area, at least one control dosimeter for each badge type and wear period will suffice. Typically, a wear period will be one month (meaning badges are exchanged monthly), two months, or one quarter.

If your account is split into groups and your dosimetry provider is shipping badges to other locations, a control dosimeter must travel with each group of badges. In this instance, the absence of a control dosimeter may result in an incorrect measurement of occupational dose.

RDC customers can purchase additional control dosimeters by contacting our Customer Care team.

What Does it Mean When My Control Dosimeter Records a Dose?

If your control dosimeter records a dose, there's no need to panic; this is a normal occurrence. The recorded dose represents the background and transit dose received on the badge from when it left our facility until it was returned.

The dose recorded on a control dosimeter is usually low and generally relatively constant from report to report. A control dosimeter will usually record a small dose (5-20 mrem per month) depending on the area of the country you live in or if air transportation is used to ship dosimeters.

When Should I Return the Control Dosimeter?

Please return your control dosimeter with all badges for the same wear period. The wear period dates are listed on each badge so you can easily tell which set a badge belongs to. All badges should be returned in the box or pre-addressed envelope provided to you in your regular shipments.

What Happens if I Accidentally Return My Radiation Dosimeter Badges Without the Control Dosimeter?

For badges returned without a control, the reported dose will include background and transit dose along with the occupational dose received by the individuals, and a subtraction of 0.18 mrem per day from the anneal to processing will be applied. However, this calculation results in an inaccurate measure of occupational dose for each badge in the group – that's why it's so important to follow the correct process for returning control dosimeters.

Next Steps for Radiation Safety

Do you want to take the next step in setting up your organization with RDC’s dosimetry badge products? Please visit our Solutions page to view our full suite of offerings.

We offer a wide range of affordable and comprehensive X-ray badge services to fit the needs of any organization, large or small. We understand that choosing a solution can be difficult, which is why our world-class customer service team is happy to provide guidance to help you make the best decision for your company.

Have a question that we did not address in this article? Please reach out to our Customer Care team, and one of our specialists will be happy to assist you.

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