A Mass-Spectrographic Study of the Isotopes of Hg, Xe, Kr, Be, I, As, and Cs

A new mass spectrometer is described which has been constructed for the purpose of making accurate determinations of relative abundances of isotopes. The high intensity and high resolving power of the apparatus allow the search for rare isotopes to be extended beyond previously attainable limits. The elements Hg, Xe, Kr, Be, I, As, and Cs have been investigated. Measurements of the relative abundances of the Hg, Xe, and Kr isotopes were made. A search was made for other isotopes than those already known, but none was found. The nonexistence of Hg¹⁹⁷ is confirmed, and the existence of Hg²⁰³ is shown to be extremely doubtful. Cs, As, and I are shown to be single to a very high degree. A search for Be⁸ revealed that if it existed it must be less than 1/100,000 of Be⁹.