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Reference areas for environmental radiation dosimetry

Tasks

  • Calibration at ambient dose equivalent rate between 10 nSv/h and 500 nSv/h
  • Determination of the response with regard to the ambient dose equivalent rate for cosmic radiation
  • Determination of the response with regard to the ambient dose equivalent rate for terrestrial radiation
  • Experimental simulation of a passing atmospheric contamination ("radioactive plume")
  • Performance of comparison measurements of active and passive dosemeters
  • Determination of the background of measuring systems
  • Long-term investigation of enviromental radiation

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Composition of natural radiation

Natural environmental radiation mainly consists of two components: terrestrial radiation which can be attributed to radioactive isotopes in the ground (e.g. potassium-40), and secondary cosmic radiation which results from primary cosmic radiation penetrating into the earth’s atmosphere.

The two components considerably differ in their composition. Terrestrial radiation is exclusively composed of gamma radiation with energies up to 2.6 MeV, whereas the ambient dose equivalent by cosmic radiation at sea level is generated to approx. 78 % by myons and electrons and approx. 20 % by neutrons. Gamma radiation contributes only less than 2 %. The energy range covers several orders of magnitude, from a few kiloelectron volt (keV) to a few hundred gigaelectron volt (GeV).

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