New Isotopes of Strontium and Barium

Abstract

APPLICATION of high resolution to accelerated anode rays has now provided improved mass-spectra of these two elements. Strontium shows a third isotope 87 in addition to those already observed. Results with barium were only obtained with great difficulty. In addition to the main line 138, they indicate the presence of no less than three of the lighter isotopes expected from the chemical atomic weight 137.36. The positions and intensities of these new lines explain the failure to observe them with the older apparatus, for with inadequate resolution their general effect would be indistinguishable from the ordinary penumbra of the strong line 138. Quantitative estimates of relative abundance will be published later. The following are the mass numbers in order of intensity: Sr 88 86 87 Ba 138 137 136 135