University of Tokyo Radiocarbon Measurements IV

The C 14 measurements reported here were made in this laboratory between January 1969 and July 1970. Details of our apparatus, sample preparation, and measuring procedure were described in R., 1968, v. 10, p. 144–148. A change has been made since January 1969: strontium carbonate is reduced to strontium carbide with a mixture of 60g of SrCO 3 to 40g of Mg-powder (<200 mesh) instead of 60g of SrCO 3 to 50g of Mg-powder (<50 mesh).