On the determination of some medium and high Z elements using charged particle activation analysis

Abstract

Charged particle activation analysis has been evaluated as a rapid, non-destructive analytical procedure for several medium-Z elements based on the detection of short-lived nuclides (1-second < T[subscript 1/2] < 5 minutes) and for use in the detection of ultra-trace quantities of the heavy metals thallium, lead, and bismuth. Utilizing proton reaction products in the 1-second to 1-minute half-life range, non-destructive analyses for Se, Br, Y, Zr, La, Pr, Dy, and Nd have been carried out in metallurgical arid biological samples. The experimental detection limits found vary from a few parts per million to a few parts per thousand depending on the matrix-impurity combination considered. In addition a number of proton and ??He-ion reaction products with half-lives from 1 to 5 minutes have been examined for trace analysis possibilities. A comprehensive survey has been made of all possible activation reactions with protons, deuterons, and ??He-ions of up to 40 MeV and ?ü?He-ions of up to 50 MeV. The reactions found to be best suited for sub-ppm determinations were for lead: [superscript 206,207]Pb(d,xn)???ü??ü?Bi; for thallium: [superscript 203,205]Tl(p,xn)???ü???Pb; and for bismuth: ???ü??ü?Bi(p,3n)???ü??ü?Po. The pertinent activation curves (relative excitation functions) have been established and radiochemical separation procedures for the respective product nuclides have been devised and evaluated. The feasibility of non-destructive and destructive analyses was studied on a series of high purity materials with heavy metal concentrations in the part per million to part per billion range using the methods described, and the analytical results are presented and discussed. Estimated detection limits are 0.01 ppm for lead and 0.001 ppm for both bismuth and thallium for 12 ??Ampere-hour irradiations. In addition to the procedure for the determination of total lead, a method is presented for the determination of ???ü??ü?Pb/???ü??ü?Pb isotope ratios.