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Unformatted text preview: Detector! • 20 keV – copper
• Energy loss sequence:
• Black • Consider a conventional BS
• Beam enters sample
• Multiple specimen interactions
result in gradual loss of energy
in primary beam electrons
• At any time, these electrons
can exit sample surface and be
• As Z increases, so does
likelihood of a scattered
electron exiting sample surface
• (An x-ray excitation event will
cause a larger energy drop in
primary beam electron)
• Modeled with a David Joy Monte
• Consider ten electrons
CBEMS 164 – XRD, SEM & Microanalysis: Lecture 11
! 10 Back-Scattered Electron Detectors – Solid State Devices!
! • Principle
– Energetic electrons excite electron-hole pairs in intrinsic
– Typically 2-4 times more BS electrons than SE electrons
• Always a BS component in an SE image
– Thin geometry allows close physical placement to specimen • Energy needed ~3.6 eV
– Each incident 10 KeV...
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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