The ³He/⁴He ratio of the new internal He Standard of Japan (HESJ)

Abstract

We have prepared an artificial mixture of ³He and ⁴He to be used as an internal standard for precise ³He/⁴He measurements of terrestrial mantle-derived samples. The mixture is named HESJ (He Standard of Japan). The ³He/⁴He ratio of HESJ was determined by obtaining the weighted average of repeated analyses from five machines in four laboratories in Japan. The recommended value of the ³He/⁴He ratio of HESJ relative to the air value (R/Ra) is 20.63 ± 0.10. HESJ is available to all researchers.