Lect13_notes

Classic rayleigh criterion for visible light

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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 dependant) •  •  •  •  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.

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