DETERMINATION OF YTTRIUM IN RARE EARTHS BY PHOTON ACTIVATION ANALYSIS

The determination of yttrium in the presence of large amounts of the rare earths by the thermal neutron reaction 89Y(n, γ)90Y is complicated because of frequent problems of sample self-shielding from major constituents of the sample, and the difficulty of separating 90Y, a pure beta-emitter, from other elements which are very similar chemically. A non-destructive photon activation analysis method has been developed for this determination. Bremsstrahlung from a 35-μA beam of 35-MeV electrons induces the photonuclear reaction 89Y(γ, n)88Y. Optimum sensitivity is obtained by coincidence counting of the 0.90 and 1.84 MeV gamma-rays associated with the decay of 88Y. The detection limit is less than 1 μg of yttrium. © 1969.