UNCLASSIFIED -SEGRET [-1175-AEC 2-30-53 » 23 - carrier, and determining the amount of ye and therefore also of BO present by absolute counting. The technique outlined above was tested and shown to yield skhtisfactory results both using inactive yttrium and neodymium as carriers for] the y* and both in the presence and absence of calcium in the solution. The] following examle of a test experiment performed with neodymium carrier and in the absence of calcium serves to illustrate the details of the chemical procegure, the counting technique, and the calculations involved in making a Sr oD assay by the milking technique. 2.005 2 Sr(C.)., were dissolved in 5C mlHC, and to it was aaded epproximately 22,000 dom of an acid solution of Sr FO _ yy tracer in equilibriun. A few ml of 85% HPO, were next added, followed by 0.304 g of Na in HC] solution. The solution was stirred and heated. I [T earrier To the hot solution . oN a NH,OH was added gradually with vigorous stirring until the precip tation of NdPO, +2E,,0 was believed to be complete. (NdPO, * 2H,,0 and YPO, +22, out completely well below pH 1, while the phosphates of calcium do not begin to precipitate until pH 3 or 4 is exceeded). To the filtrate were added a few ml of 2 precipitation occurred, showing that the precipitation of neodymi camplete. ad strontium The pr elpitate was digested with heating for 15 minutes, filtered onto a f-cm f and washed with water. precipitate ter paper, NH,08. No had been Additional NE,OH was now added to the same solution un il SrHP0, was precipitated completely. The SriPo, vas also filtered onto 7 m paper. The precipitates were dried and mounted onto lucite semicylinders of 1-7/8" a [045324 i i ee SECRET Y Cd UNCLA SSIFIED *