Survey Information

Your RUA will outline the minimum frequency required for documented surveys, but you are required to perform self-surveys routinely while you work with radioactivity or radiation, as they are the primary tool for detecting contamination and measuring radiation fields.

How Do I:

Use a Survey Meter?

  1. Verify that the instrument is in calibration by checking the calibration sticker on the side of your instrument and confirming that the dates reflect a current calibration.
  2. Turn on your meter, as well as the audio and confirm that the batteries are good. Low batteries will give inaccurate readings.
  3. Verify that the probe is responding to radiation by placing the probe by a source of radioactivity such as a check source or your stock solution and confirming that it responds. If it does not respond, contact Radiation Safety for assistance.

In general, you should avoid wrapping the detector probe with a mylar, parafilm, or plastic as this will eliminate (or at least significantly reduce) the instrument’s response to low energy betas particles.

Hand-held survey meters will not detect tritium (H-3) - swipe tests with a Liquid Scintillation Counter are required. Accurate surveying requires you to survey close to an object and to move slowly.

For information on how to perform a survey read the section "Perform a Swipe Survey and use a Liquid Scintilation Counter (LSC)?".

Calibrate or Repair my Survey Meter?

Calibration and repair of instruments can be obtained from:

  1. EH&S, Radiation Safety
    University Hall
    Phone (510) 642-3073, E-mail: radsafety@berkeley.edu
  2. Ludlum Measurements, Inc. 
    501 Oak Street, Sweetwater TX 79556
    Phone (800) 622-0828
  3. Thermo-Fisher Scientific
    Phone 1 (800) 274-4212
  4. Radiation Detection Co. for instrument calibration
    8095 Camino Arroyo, Gilroy, CA 95020
    Phone (800) 250-3314, option 1

UC Berkeley’s radioactive materials license requires each instrument be calibrated at least once a year and after repair. When our records indicate that you have a meter(s) that is due for calibration, we will contact you to make arrangements to calibrate your instrument(s). Note that some meters will require calibration by an outside vendor. Make sure to also provide EH&S with a copy of the calibration paperwork that you receive from the vendor so that we can update our records.

Questions regarding portable radiation survey meters?

Call the Radiation Safety Team at (510) 642-3073 for information. For more information on how to survey your lab areas read our guidelines for how to survey your lab.

Perform a Swipe Survey and use a Liquid Scintilation Counter (LSC)?

In order to determine if there is any unfixed contamination in the lab, swipe (or wipe) surveys are the best tool. These swipes will then be counted in an appropriate radiation detector, usually a liquid scintillation counter (LSC). Swipe tests are the only reliable method of determining H-3 contamination without special equipment.

Contact Radiation Safety if you need help identifying an LSC for you to use.

Taking Swipes

Be sure to use appropriate media (paper filters, cotton swabs, glass fiber filters, etc.) and adequately cover the laboratory. Each swipe should cover at least 100 cm2, which can be accomplished by using medium pressure and drawing an “S” over a 2’x2’ (60cm x 60cm) square. These swipes should then be segregated to prevent cross contamination between swipes before counting.

Counting Swipes

Swipes should be loaded into an appropriately sized LSC vial. LSC cocktail (counting fluid) will then be added to the vial and then the vials will be placed into LSC racks and counted. Be sure to use a counting protocol that is programmed to detect the radionuclides being used by your lab. A background sample (a clean swipe in cocktail) should be prepared and run along with your swipes. Contamination is considered to be any swipe sample that is found to have a count rate greater than two times the count rate of the background sample.

Addressing Contamination

All contamination outside of radioactive work area must be cleaned  and resurveyed until the count rate is below two times background. Contamination limits inside radioactive work areas are outlined in the Radiation Safety Manual. Contact Radiation Safety if you are having difficulty with any decontamination efforts or if you have any questions about setting up LSC protocols, counting consumables, or other general questions.

Decontaminate an Area?

  1. Place absorbent materials at the edges of the spill if it is spreading.

  2. Begin the decontamination process from the edges of the spill working inward.  Use decontamination solution (or soap and water) and paper towels to decontaminate the area.

  3. Working  in small (12" by 12" square) areas you will reduce the spread of contamination.

  4. As you decontaminate the area, use swipes to find out how much contamination there is, where it is, and how effective  your efforts are to remove the contamination as you proceed.

  5. Be careful to stay out of the spill, absorb any liquids by placing paper towels on top of the spill.

  6. Carefully place all contaminated papers and materials in a properly labeled radioactive waste bag as you go.

  7. When you think that you have the spill cleaned up, take swipes of the spill area and of  surrounding areas such as doorways, adjacent hallways, elevators, and shoes. Keep cleaning until the area is clean (below twice background).

  8. Document the spill findings, your final survey, and any notes that you may need to refer to in the future. Keep your self-surveys and swipe data.

Remember to monitor all persons, equipment, and waste being moved from the spill area. Handle contaminated materials as radioactive waste.