Standardization of a 89Sr solution from a BIPM intercomparison using a liquid scintillation method

A procedure to standardize 89Sr (as strontium chloride) solutions, within the frame of a BIPM intercomparison, by the CIEMAT/NIST method was presented for Instagel Plus, HiSafe III and Ultima Gold liquid scintillation cocktails. The stability was studied for two types of samples: those obtained by direct addition of the 89Sr solution and those by the extra addition of 0.5 ml of HCl (0.1 mol l−1) to the cocktails. The results only showed good stability with the three scintillants used when additional HCl was added to the cocktails. The activities per unit mass determined for 89Sr were: 26.344 kBq g−1 for Instagel Plus; 26.335 kBq g−1 for HiSafe III; and 26.310 kBq g−1 for Ultima Gold (at a reference time of 2000.10.01, 00 h UT) with a total uncertainty of 0.5% in each case (k=1).