A wipe test counter is a device used to measure for possible

radioactive contamination Radioactive contamination, also called radiological pollution, is the deposition of, or presence of Radioactive decay, radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is uni ...

in a variety of environments. When using radioactive materials it is necessary to test for accidental contamination, whether from use of liquid unsealed

sources Source may refer to: Research * Historical document * Historical source * Source (intelligence) or sub source, typically a confidential provider of non open-source intelligence * Source (journalism), a person, publication, publishing institute ...

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 A test tube, also known as a culture tube or sample tube, is a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top and closed at the bottom. Test tubes are usually placed in s ...

and counted, typically using a

gamma counter A gamma counter is an instrument to measure gamma radiation emitted by a radionuclide. Unlike survey meters, gamma counters are designed to measure small samples of radioactive material, typically with automated measurement and movement of multip ...

. Testing for leaks in this manner is a method described in the

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

9978 standard.

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. 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 A scintillator ( ) is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the ab ...

and

photomultiplier tube Photomultiplier tubes (photomultipliers or PMTs for short) are extremely sensitive detectors of light in the ultraviolet, visible light, visible, and near-infrared ranges of the electromagnetic spectrum. They are members of the class of vacuum t ...

and may allow the

energy spectrum In the physical sciences, the term ''spectrum'' was introduced first into optics by Isaac Newton in the 17th century, referring to the range of colors observed when white light was dispersed through a prism. Soon the term referred to a plot o ...

of a sample to be recorded, which can be used to identify the contaminant. Use of a

gamma camera A gamma camera (γ-camera), also called a scintillation camera or Anger camera, is a device used to image gamma radiation emitting radioisotopes, a technique known as scintigraphy. The applications of scintigraphy include early drug development ...

has also been proposed, where collimators are removed to improve sensitivity.

Regulation

Wipe testing is typically a requirement of licenses to hold radioactive materials. In the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

the

Nuclear Regulatory Commission The United States Nuclear Regulatory Commission (NRC) is an independent agency of the United States government tasked with protecting public health and safety related to nuclear energy. Established by the Energy Reorganization Act of 1974, the ...

requires wipe testing of sealed sources "periodically" using equipment sensitive down to 185

Becquerels The becquerel (; symbol: Bq) is the unit of radioactivity in the International System of Units (SI). One becquerel is defined as an activity of one per second, on average, for aperiodic activity events referred to a radionuclide. For applicatio ...

. In the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

the

Health and Safety Executive The Health and Safety Executive (HSE) is a British public body responsible for the encouragement, regulation and enforcement of workplace health, safety and welfare. It has additionally adopted a research role into occupational risks in Great B ...

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 The Environment Agency (EA) is a non-departmental public body, established in 1996 and sponsored by the United Kingdom government's Department for Environment, Food and Rural Affairs, with responsibilities relating to the protection and enha ...

permits. In

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

licence conditions may require adherence to Australian standard AS2243.4 and ISO 9978 for wipe testing of sealed sources.

References

{{DEFAULTSORT:Wipe Test Counter Radiation health effects Particle detectors