Scanning Electron Microscopy and X-Ray Microanalysis

354

21

Photon energy (keV)

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0

. Fig. 21.14 Sequence of measurements for determining pathological
scattering effects by the “in-hole” method. For the same dose, EDS spectra
are measured on the brass block, aluminum stub, platinum aperture, and

at the center of the 200 μm diameter hole of the platinum aperture. A

logarithmic display reveals the very low counts in the “in-hole” spectrum

compared to the spectra measured on the various materials

EDS

detector

window

Collimator &

electron trap

Final

lens

Chamber

wall

Aperture

scattering

Conventional SEM,

pathological scattering

“In-hole Spectrum”

Green =

Extent of

specimen

X-ray sources

NOT excluded

by collimator

Multi-material Faraday Cup “in-hole” test specimen

. Fig. 21.13 Measurement of
“in-hole” spectrum with a
multi-material Faraday cup
consisting of three materials
arranged concentrically

Chapter 21 · Trace Analysis by SEM/EDS