Detection and Quantification Problems in the Analysis of Light Elements With UTW Detectors

Recent developments in windowless (WL) or ultra-thin window (UTW) detectors, improved energy resolution, larger angles of collection (0.15-0.2 sterad), higher voltages (200-400 kV) make energy dispersive spectrometry more attractive for the analysis of low Z elements down to beryllium (Ref. 1 and Fig. 1). It lends itself to faster, more routine analysis and offers in many cases the possibility of carrying out qualitative analysis for a wider range of materials thickness. It has, however, generally been recognised to have lower sensitivities than EELS except for some elements in biological materials. Also, UTW analysis have been restricted to qualitative analyses, largely due to the large absorption even for relatively thin samples. This paper presents results that can typically be achieved with both SEM and TEM’s, difficulties in quantifying the data and the sensitivity that can be expected. The detectors (Link LZ-4 and Link LZ-5) on both our SEM (JEOL 840) and TEM (JEOL 2000FX) have a resolution of ≈ 134 ev at 5.9 kev and allow the detection of boron from pure B with the peak well resolved from the background and a peak/valley ration of 12.