Electron-probe microanalysis of low atomic number elements

Decontamination in the Electron Probe Microanalysis with a Peltier-Cooled Cold Finger

“…During spot analysis, carbon contamination forms ring shape deposits as hydrocarbons cracked by the electron beam deposit adjacent to the beam position (e.g., Castaing & Descamps, 1954; Ranzetta & Scott, 1964; Fourie, 1976). In this study, contamination is quantified using BSE images calibrated for carbon thickness.…”

Electron probe microanalysis using soft X‐rays – a review. Part 1: Instrumentation, spectrum processing and detection sensitivity

“…The method was very successful; not only could it measure light element concentrations of a few wt.%, but there was also sufficient X‐ray signal to produce X‐ray maps of elements down to, and including, beryllium (Dolby, 1963). Figure 13(a) was obtained using a four‐channel network system (Ranzetta & Scott, 1964) built with Dolby's co‐operation and fitted to a very early scanning electron‐probe microanalyser. This is a carbon X‐ray map showing the presence of uranium carbides in uranium and it is instructive to compare the contrast achieved with that obtained when using a lead stearate crystal available at the time, see Fig.…”

Low-Voltage Electron-Probe Microanalysis of Uranium

“…Electron-probe microanalysis (EPMA) has been an invaluable tool for the nuclear industry since its very earliest days. The first EPMA spectra acquired on Pu were reported in 1961 (Scott, 1961), and within a few years, the technique was being used to measure Fe, C, and Ga contents in Pu (Scott & Ranzetta, 1961;Hakkila et al, 1964;Ranzetta & Scott, 1964) for the analysis of U-alloys (Colby, 1963(Colby, , 1966 and for inclusions in UO 2 (Jeffery, 1967). The ability of EPMA to provide the nondestructive analysis of almost the entire periodic table down to trace-level (less than ∼100 ppm) detection limits at micron-scale resolutions (Reed, 1975) is particularly valuable to an industry, where the materials are often only available in small quantities, are difficult to handle and prepare, and where the disposal of excess waste is extremely costly.…”

“…U-metal and U-alloys pose several problems for microanalysis: U oxidizes extremely readily, growing a surface oxide film of several nanometers almost instantly on contact with air (Ranzetta & Scott, 1964;Bowles, 1978;Younes et al, 2007); being a high Z element U emits a large number of x-ray lines (e.g., Bearden (1967) lists 80 lines for U), increasing the potential for overlaps when analyzed in the presence of other elements (Ranzetta & Scott, 1964;Jeffery, 1967;Walker, 1999); and absorption corrections are large and not well constrained. These problems are exacerbated when analyzing at lower accelerating voltages in order to investigate smaller and smaller features, since the energies of x-ray lines that can be excited are decreased, forcing the use of lower energy x-ray lines for analysis.…”

“…These problems are exacerbated when analyzing at lower accelerating voltages in order to investigate smaller and smaller features, since the energies of x-ray lines that can be excited are decreased, forcing the use of lower energy x-ray lines for analysis. For example, for U this means using the M-lines, for which the correction factors are larger and even less well characterized than the L-lines (Ranzetta & Scott, 1964;Bowles, 1978;Romig, 1984).…”