Codes & Standards - Purchase
ISO 6980-1:2006 proposes two series of beta reference radiation fields from which the radiation necessary for determining the characteristics (calibration and energy and angular dependence of response) of an instrument can be selected.
Series 1 reference radiation fields are produced by radionuclide sources used with beam flattening filters designed to give uniform dose equivalent rates over a large area at a specified distance. The proposed sources of 90Sr + 90Y, 85Kr, 204Tl and 147Pm produce maximum dose equivalent rates of approximately 200 mSv h-1.
Series 2 reference radiation fields are produced without the use of beam-flattening filters, which allows large area planar sources and a range of source-to-calibration plane distances to be used. Close to the sources, only relatively small areas of uniform dose rate are produced but this series has the advantage of extending the energy and dose rate ranges beyond those of series 1. The radionuclides used are those of series 1 with the addition of the radionuclides 14C and 106Ru + 106Rh; these sources produce dose equivalent rates of up to 10 Sv h-1.