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Unformatted text preview: ay photon cannot exceed energy of electron
exciting the photon. CBEMS 164 – XRD, SEM & Microanalysis: Lecture 13
! 15 Microscopy and the Concept of Resolution!
Classic Rayleigh Criterion for
Visible Light Microscopy δ=
δ= 0.61 λ
µ sin β
Smallest distance that
can be resolved Louis de Broglie’s Equation λ= 1.22
E1 2 100 keV electron: λ 4 pm ( 0.004 nm ) CBEMS 164 – XRD, SEM & Microanalysis: Lecture 13
! 16 The Pieces of the Pie!
• Electron beam impinges on sample
– Interacts with sample within an interaction volume
– Energy loss in incident beam during multiple interaction events result in
characteristic and background x-radiation • X-rays leave point of creation in all directions
– Intensity generated is f(Z)
– Some get absorbed
– In so doing, can cause fluorescence of other x-ray lines (chemistry
• An energy dispersive detector collects the resulting x-rays
Displays the familiar EDS spectrum
Extract peak intensities from spectrum
But these do not exactly correspond to t...
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This note was uploaded on 01/16/2014 for the course CBEMS 164 taught by Professor Porter,j during the Fall '08 term at UC Irvine.
- Fall '08