More Information About the Surveys and the Thermoluminescent Dosimeters | Region 10 | US EPA

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More Information About the Surveys and the Thermoluminescent Dosimeters

Southeast Idaho Phosphorus Slag Program

Surveys are performed with instruments that measure radiation and identify specific locations in the buildings where radiation exceeds natural background levels. Surveys measure radiation dose rates (for example, dose per hour) and in most cases can tell you whether your building has radiation levels above background, indicating that slag may be present.

The survey team will make an appointment with you, and you must be present to have the survey conducted. Once you have given your permission to the team to enter your building, team members will check for radiation levels that are higher than would be expected for Southeast Idaho. Measurements will be taken on the main floor and in the basement. The team will spend only a few minutes in your building. If the measurements do not show significant levels of radiation in your building, you will be given a statement of the team's findings. If elevated radiation levels are found, the team will inform you that the measurements indicate you may have slag in your building and recommend more extensive measurements.

Thermoluminescent Dosimeters are small devices that measure radiation dose over time. Normally, TLDs are used for a period of three months and then processed to determine the total dose accumulated during the period of exposure.

To find out how much radiation you are being exposed to, you can sign up to use a thermoluminescent dosimeter, or TLD. A TLD is an instrument that measures how much radiation a person is being exposed to. You can make an appointment to pick up a TLD by calling the District Health Department in Pocatello or Soda Springs. During your appointment, you will be given a demonstration for proper use of the TLD. TLDs are small enough to be used on a key ring, which is how it is recommended you use it.

In order to obtain a measurement that reflects your living habits, a TLD should be used for a period of three months. That means that you need to carry it with you, or have it near you, at all times. For example, you could place it on a bedside table at night while you sleep. After three months, you should bring the TLD back to the District Health Department, which will have it processed and provide you with your results within three weeks.

Comparison of Surveys and Thermoluminescent Dosimeters

Surveys measure the rate of radiation dose in a specific locationTLDs measure radiation dose for a specific individual or a specific location within a building over time
Surveys provide immediate results.TLDs must be used over a period of three months.
Homeowners must provide access to indoor house locations, and the method is somewhat intrusive for study participants. While TLDs are less intrusive, individuals wearing TLDs must keep the dosimeter on or near them over the required three-month time period.

I wear a TLD at work because I am exposed to radiation as part of my job. Should I wear the TLD for the phosphorus slag program to work as well?
Yes. This program is designed to assess total exposure to radiation, including radiation doses received at work and doses received at home. Subtracting the radiation dose you receive at work from the total dose measured by the TLD will help determine how much radiation you are being exposed to at home. If you were to leave the TLD at home, it would tell you only what radiation dose you would receive if you stayed at home all the time.

Should everyone in our family get their own TLD?
That's up to you. It does require some effort to keep track of the TLD for three months. What you might consider is having the person who spends the most time at home wear the TLD. If the results indicate elevated radiation exposures, other family members can always decide to wear a TLD later.

What if the building survey or TLD indicates exposure rates that are higher than expected?
If the initial building survey or TLD indicates that you may be exposed to elevated radiation levels, more extensive measurements will be recommended. These measurements will help you find out exactly where in your building you are being exposed to radiation. participate in the more extensive dose rate measurements, you need to make an appointment by calling the District Health Department.

First, the building owner must grant permission to the team members to enter the building and perform detailed measurements. Then, they will visually inspect the building to look for physical evidence of slag. Next, they will measure the radiation dose rate in every room in the building using a meter that measures radiation levels. Finally, they will provide detailed time logs to be used in calculating each individual's radiation dose.

Southeast Idaho Phosphorus Slag Homepage

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