Faculty and Staff

How to Perform a Radiation Survey

Last updated September 3, 2009 4:23:14 PM PDT
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Routine surveys are required to detect incidental radiation contamination that may occur during research activities. Learn about survey methods and how to document the results.

Read Radiation Contamination Survey Overview to determine the appropriate survey method for your lab.

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Document lab surveys.

Keep survey documents where they can be easily retrieved upon request by inspectors.

  • Use 1 of the forms below to document your radiation surveys:
    • Laboratory Meter Survey Record (PDF) (Word)
    • Laboratory Survey Sheet, which records either a meter survey or wipe test results (PDF) (Word)
  • Keep survey documents on file for 3 years.

Follow these steps to perform a meter (direct) survey.

Survey using a meter and probe
Radiation survey using a meter and probe.

Survey the benchtop, equipment, and inventory and waste storage areas. Check clothing, hands, shoes, regular trash, and the work area floor.

Note: Do not use this method for tritium. Use the wipe test method instead.

  • Check the meter's battery condition, then set the range.
  • Meters will detect some background radiation, so take a background reading in a clean area before every meter survey.
  • Hold the probe within 1/2 inch of the surface. Sweep the area or item at a rate of 1 to 2 inches per second.
  • Readings statically different than background indicate contamination.

Follow these steps to perform a wipe test (indirect) survey.

Wipe testing
Radiation survey using wipes.

Take enough wipe samples to confidently survey the radioactive materials use area, including the benchtop, equipment, floor, and inventory and waste storage areas.

  • Use the wipe test method:
    • If you use tritium
    • In areas where contamination is detected with a meter
    • In areas where meter monitoring is impractical (inside a microfuge, for example)
    • In areas where very small amounts of activity are used (less than 1 microcurie)
  • To detect background radiation, set up a clean filter or cloth wipe as a blank.
  • Using filter paper or cloth wipes, wipe an area of 16 square inches (100 square centimeters) for each sample.
  • Analyze the samples using a liquid scintillation counter or gamma counter.
  • Areas with readings exceeding these values (in dpm/100 sq cm) are contaminated:
    Emission Example isotopes Loose
    Beta C-14, P-32, P-33, S-35 1,000
    Photon Ca-45, Cr-51, Mn-54, 1,000
    Photon I-125, I-131 200
    Alpha Pb-210, Ra-228 20
    Various U-nat, U-dep, Th-nat 200

Clean up contamination.

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Need an expert? Contact EH&S Radiation Safety, (858) 822-2494.

Notice: Refer to the Radiation Safety Manual (PDF) (Word file) for a detailed description of UCSD's radiation safety program.