Wipe test counter

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]

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]