How to Use a Geiger Counter

If your lab is authorized to use radioactive Materials, you are required to conduct routine contamination surveys. Contamination Surveys are required to be performed weekly after each radioactive material use. We encourage researchers to perform contamination Surveys after each individual experiment. Your surveys should include the Geiger meter survey and wipe tests. The lab areas that must be scanned include the bench top or work surface, floor near the work area, centrifuges, waste containers, waste storage areas, and isotope storage locations. The fol-lowing provides information on how to use the Geiger Counter.

Note H3 and C14 will not register on Geiger Meter.


  • Check the calibration sticker to confirm that Geiger Counter has been calibrated within last 12 months.
  • Conduct battery test.

Change multiplier to Batter Test (BAT) position and confirm that needle is over BAT test region on Geiger Meter scale.


  • Switch Audio to ON position.
  • Switch Fast/Slow to F position.
  • Turn multiplier from OFF position to one of the multiplier options, starting at the lowest multiplier position (x0.1) and increasing as necessary.
  • Slowly scan 1” above the surface moving 2-3” per second.
  • Use audio beeping noise to guide you to areas that have higher levels of contamination
  • Rapid beeping indicates higher levels of radioactive contamination.


  • Use middle mR/hr scale for all multipliers except x100.
  • Multiply the reading on the center scale by the multiplier dial. For instance, on the x10 multiplier, the reading is 0.8×10= 8.0 mR/hr.
  • Use bottom mR/hr scale for x100 multiplier.

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