Ion Microprobe Mass Analyzer

Abstract

The quantitative analyses and other applications described in this article indicate a useful future for the ionmicroprobe mass analyzer in many areas of the science of solid materials. It should be possible to analyze all the elements quantitatively, but detection sensitivities will vary depending on the matrix, the element, and the polarity of the sputtered ion being studied. Most elements will have optimum yields in the spectrum of positive sputtered ions, and will be detected in concentrations of parts per million in micrometer-sized sampling areas. Electronegative elements will be detected with similar sensitivities in the spectrum of negative sputtered ions, but inert gases, which are ionized with difficulty and have small electron affinities, will be detected with considerably poorer sensitivities. In general, it will be possible to measure isotope ratios without chemical separation of the constituent elemrents of the sample. The precision of an ion microprobe isotope ratio measurement depends basically on the counting rates involved, and its accuracy can approach its precision if auxiliary standards are used. The isotope ratios of different elements can be compared readily because of the small mass-discrimination effects of the system. Surface layers can be quantitatively analyzed in depth with a resolution of tens of angstroms; hence, it should be possible to study the migration of atoms.

Imaging mass spectrometry demonstrates age-related decline in human adipose plasticity

“…MIMS is made possible by an ion microscope (NanoSIMS) (15), which incorporates principles of secondary ion mass spectrometry (16,17) and state-of-the-art ion optics. A sample surface is sputtered with a focused primary ion beam, triggering emission of atoms and molecular fragments, a fraction of which are ionized and transmitted to a mass spectrometer.…”

Estimation of picked-up lunar ions for future compositional remote SIMS analyses of the lunar surface

“…The application of the Saha equation describing the charge state distribution probabilities of plasma is efficacious to quantitative SIMS analyses (Andersen and Hinthorne, 1972). In laboratory quantitative SIMS analysis, however, the relative sensitivity to the standard sample is generally utilized because the interaction between secondary ions and their matrix, which is called the 'matrix effect', strongly affects the absolute yield of secondary ions.…”

Radiohalos in Coalified Wood: New Evidence Relating to the Time of Uranium Introduction and Coalification

“…The fact that just the oppo site is true is in good agreement with the evi dence found by Jedwab (1) and private commu nication] indicating that during the U infiltration the gel-like wood exhibited much higher sensitiv ity to a induced coloration as compared to the later stages of coalification. Possibly then, a relatively dark halo could have formed rather quickly from as few as 10 4 to l0 5 Po atoms, whereas some 20 to 50 years later the change in the coloration sensitivity of the matrix might require an a-dose 50 to several hundred times higher from the 210 Pb decay sequence to produce even a light halo. Thus possibly only in rare cases would the Pb-Se inclusions accumulate large enough quantities of 2 "'Pb to subsequently generate the outer circular halo.…”