EH&S is responsible for calibrating portable survey instruments at Iowa State University. When the instrument is due for calibration, an EH&S staff member will inspect, inventory, and calibrate the meter. A calibration sticker is affixed to the instrument, indicating the date of calibration, when the next calibration is due, and the name of the calibrator. However, lab personnel are responsible for ensuring that they are using a meter with current calibration. Do not use a meter that has not been calibrated within the last 12 months. Call EH&S at (515) 294-5359.
Portable / Handheld Instruments
- The Geiger-Mueller (GM) detector is a common portable instrument choice for a general laboratory radioactive material survey.
- GM detectors are capable of detecting alpha, beta, and gamma radiation. However,this instrument is limited by its ineffectiveness for detecting lower energy beta and gamma emittters.
- The end-window or pancake Geiger-Mueller is a great instrument for detecting medium- to high-energy beta emitters, such as Phosphorus-32, Phosphorus-33, Chlorine-36, or Calcium-45.
- Due to its poor efficiency for detecting some kinds of radiation, a Geiger-Mueller instrument is not effective for detecting low-energy beat emitters, such as Hydrogen-3, Carbon-14 or Sulfur-35. It is also not effective for low-energy gamma emitters, such as Iodine-125 or Iodine-131.
- The NaI Scintillation detector is another type of portable detector for general laboratory radioactive material surveys.
- NaI detectors are capable of detecting low-energy gamma radiation.
- The NaI is a great instrument for detecting low-energy gamma emitters, such as Chromium-51, Iodine-125, Iodine-131, or Iron-59.
- Due to its poor efficiency for detecting some kinds of radiation, a NaI detector instrument is not effective for detecting beat emitters, such as Hydrogen-3, Carbon-14, Phosphorus-32, Phosphorus-33, Chlorine-36, or Sulfur-35.
- Portable Meter Operations Check (PDF)
- Liquid Scintillation Counter
- For detecting low-energy beta emitters, such as Hydrogen-3(Tritium), Carbon-14, or Sulfer-35, a liquid scintillation counter (LSC) must be used. You will need to have wipes and prepare vials for counting.
- Please note that a liquid scintillation counter can be used to monitor any radionuclide.
- Recording routine background and standard counts and running the LSC’s normalization or calibration procedure will ensure that the LSC is operating correctly. EH&S has a liquid scintillation counter available for your use if your LSC fails to operate correctly.
- Contact EH&S if you have questions about operating a LSC or wish to use the EH&S LSC.
- Calibration and Normalization of Liquid Scintillation Counters (LSC) (PDF)