Letter | Published:

British Standard of Radioactive Iodine-131

Naturevolume 199page898 (1963) | Download Citation



IN 1952 it was agreed1 to define the above standard in terms of the γ-ray dose-rate in air at 1 cm from a point source of 1 mc. of iodine-131. Such a procedure, utilizing a graphite ionization chamber, resulted at that time in greater precision and reproducibility than could be obtained by particle counting. It was estimated that the derived disintegration rate would not differ from the absolute value by more than ± 5 per cent.

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  1. 1

    Nature, 170, 916 (1952).

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  1. Applied Physics Division, National Physical Laboratory, Teddington

    • W. J. CALLOW


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