

New (super 14) C reference materials with activities of 15 and 50 pMC.
Abstract
Two new (super 14) C reference materials have been developed for international use, filling a gap in the present C1-C6 series available from the IAEA. By mixing a modern and a synthetic substance, 150 kg of C7 (ca. 50 pMC activity) and C8 (ca. 15 pMC activity), respectively, were obtained.
Keywords
natural materials;recrystallization;synthetic materials;mixing;chemical reactions;carboxylic acids;oxalic acid;standard materials;organic acids;isotope ratios;organic compounds;C 14;carbon;isotopes;radioactive isotopes;C 13 C 12;stable isotopes