Editing Background radiation (section)

==Radiation metrology==
In a radiation metrology laboratory, '''background radiation''' refers to the measured value from any incidental sources that affect an instrument when a specific radiation source sample is being measured. This background contribution, which is established as a stable value by multiple measurements, usually before and after sample measurement, is subtracted from the rate measured when the sample is being measured.

This is in accordance with the [[International Atomic Energy Agency]] definition of background as being "Dose or dose rate (or an observed measure related to the dose or dose rate) attributable to all sources other than the one(s) specified.<ref name="IAEA Safety Glossary 2007"/>

The same issue occurs with radiation protection instruments, where a reading from an instrument may be affected by the background radiation. An example of this is a [[scintillation detector]] used for surface contamination monitoring. In an elevated gamma background the scintillator material will be affected by the background gamma, which will add to the reading obtained from any contamination which is being monitored. In extreme cases it will make the instrument unusable as the background swamps the lower level of radiation from the contamination. In such instruments the background can be continually monitored in the "Ready" state, and subtracted from any reading obtained when being used in "Measuring" mode.

Regular Radiation measurement is carried out at multiple levels.  Government agencies compile radiation readings as part of environmental monitoring mandates, often making the readings available to the public and sometimes in near-real-time.  Collaborative groups and private individuals may also make real-time readings available to the public.  Instruments used for radiation measurement include the [[Geiger–Müller tube]] and the [[Scintillation detector]].  The former is usually more compact and affordable and reacts to several radiation types, while the latter is more complex and can detect specific radiation energies and types.  Readings indicate radiation levels from all sources including background, and real-time readings are in general unvalidated, but correlation between independent detectors increases confidence in measured levels.

'''List of near-real-time government radiation measurement sites, employing multiple instrument types:'''
* Europe and Canada: European Radiological Data Exchange Platform (EURDEP) [https://remap.jrc.ec.europa.eu/GammaDoseRates.aspx  Simple map of Gamma Dose Rates]
* USA: EPA Radnet [https://www.epa.gov/radnet/near-real-time-and-laboratory-data-state near-real-time and laboratory data by state]

'''List of international near-real-time collaborative/private measurement sites, employing primarily Geiger-Muller detectors:'''
* GMC map: http://www.gmcmap.com/ (mix of old-data detector stations and some near-real-time ones)
* Netc: http://www.netc.com/
* Radmon: http://www.radmon.org/
* Radiation Network: http://radiationnetwork.com/
* Radioactive@Home: http://radioactiveathome.org/map/ {{Webarchive|url=https://web.archive.org/web/20160329050624/http://radioactiveathome.org/map/ |date=29 March 2016 }}
* Safecast: [http://safecast.org/tilemap/?y=0&x=0&z=3 http://safecast.org/tilemap] (the green circles are real-time detectors)
* uRad Monitor: http://www.uradmonitor.com/