The Sensitivity Factors of the Rare Earths in an rf Spark Source Mass Spectrograph

Abstract

Experimentally determined sensitivity factors for the rare earths in Y₂O₃ are presented along with computed values based upon some electrical and physical properties of the elements and compounds. The sample electrodes consisted of 2 mol of pelletizing graphite and 1 mol of Y₂O₃ powder. The properties considered are (1) the heat of formation of the gaseous metal, (2) the dissociation energy of the monoxide, (3) the ionization potential of the metal, and (4) the experimentally determined charge distribution of the metal ions in the rf spark ion source. Even for the rare earths, a class of elements with similar chemical and electrical properties, the experimentally determined and computed sensitivity factors differ by as much as a factor of 6 from one another.