Wipe test counter

A wipe test counter is a device used to measure for possible radioactive contamination in a variety of environments. When using radioactive materials it is necessary to test for accidental contamination, whether from use of liquid unsealed sources or to check for leaking sealed sources. A swab or small absorbent smear can be used to “wipe” an area, the wipe is then placed into a test tube and counted, typically using a gamma counter. Testing for leaks in this manner is a method described in the ISO 9978 standard.[1]

Equipment

Survey instruments may be used to detect surface contamination without requiring wiping, however this requires careful calibration and technique to ensure adequate sensitivity is achieved.[2]

A gamma counter is a typical choice for measuring wipe samples for radioactivity as it allows multiple tests to be counted in a largely automated way. These systems detect radiation using a scintillator and photomultiplier tube and may allow the energy spectrum of a sample to be recorded, which can be used to identify the contaminant.[3][4]

Use of a gamma camera has also been proposed, where collimators are removed to improve sensitivity.[5]

Regulation

Wipe testing is typically a requirement of licenses to hold radioactive materials. In the United States the Nuclear Regulatory Commission requires wipe testing of sealed sources "periodically" using equipment sensitive down to 185 Becquerels.[6] In the United Kingdom the Health and Safety Executive guidance for the Ionising Radiations Regulations 1999 requires wipe testing (usually every two years) and it is also likely to be a requirement of Environment Agency permits.[7][8] In Australia licence conditions may require adherence to Australian standard AS2243.4 and ISO 9978 for wipe testing of sealed sources.[9]

gollark: We will use approval voting. You can vote for people who are not lyric.
gollark: They *may* be mildly evil and also appear to make claims to objectivity which I don't think are valid.
gollark: So more people have time to do things.
gollark: Hey, I'm running too.
gollark: THINGS.

References
  1. "ISO 9978:1992 Radiation protection -- Sealed radioactive sources -- Leakage test methods" (PDF). Public.Resource.Org. Retrieved 27 February 2017.
  2. "Information Notice No. NO. 93-30: NRC Requirements for Evaluation of Wipe Test Results; Calibration of Count Rate Survey Instruments". Nuclear Regulatory Commission. 12 April 1993. Retrieved 27 February 2017.
  3. Rayburn, Stephen R (1990). The Foundations of Laboratory Safety a Guide for the Biomedical Laboratory. New York, NY: Springer New York. p. 206. ISBN 9781461233206.
  4. Lombardi, Max H (2006). Radiation Safety in Nuclear Medicine (2nd ed.). Hoboken: CRC Press. p. 129. ISBN 9780849381799.
  5. Friede, Juan; Dumesnil, Cecile; Caron, Camille (1990). "Gamma Camera and Computer-Assisted Wipe Tests: A Simple Method". Journal of Nuclear Medicine Technology. 18 (1): 49–51. ISSN 0091-4916.
  6. "10 CFR 39.35 Leak testing of sealed sources". Nuclear Regulatory Commission. Retrieved 27 February 2017.
  7. Health & Safety Commission (2000). Work with ionising radiation : Ionising Radiations Regulations 1999 approved code of practice and guidance. London: HSE Books. ISBN 9780717617463.
  8. "Sealed sources: how to comply with your EPR RSR environmental permit". Environment Agency. 2011. Retrieved 27 February 2017.
  9. "Wipe Testing of Sealed Sources & Use of Sealed Sources Beyond Recommended Working Life" (PDF). Australian Radiation Protection and Nuclear Safety Agency. February 2013. Retrieved 27 February 2017.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.