This preview shows page 1. Sign up to view the full content.
Unformatted text preview: icroanalysis: Lecture 13
! 32 ZAF factors in Microanalysis!
Atomic Number Effect: X-ray Absorption Effect: Fluorescence Effect: Z – Atomic Number Effect! • Backscattering, R
– Some electrons are backscattered and leave
sample without exciting an x-ray
• No energy loss therefore no x-ray
• BS electron yield from a Au:1 Al alloy will be dominated
by the Au and this must be accounted for if a pure Al
standard is used for Al analysis.
• Can model with Monte Carlo simulations • Energy Loss, S
– Rate of energy loss due to inelastic scattering
depends on Z CBEMS 164 – XRD, SEM & Microanalysis: Lecture 13
! 33 CBEMS 164 – XRD, SEM & Microanalysis: Lecture 13
! 34 A- X-Ray Absorption Effect! • Once generated, x-rays have
to traverse sample until they
exit the top surface
– Some are absorbed, possibly
ejecting inner shell electrons
from their sites - inner shell
– Higher keV results in a longer
traverse path I/I0 = exp[-(µ/)(t)]
µ/ is mass absorption coefficient F - Flourescence! • Ionizations of inner atomic shells can result...
View Full Document
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