Transcript Slide 1

Part of
MATERIALS SCIENCE
& A Learner’s Guide
ENGINEERING
AN INTRODUCTORY E-BOOK
Anandh Subramaniam & Kantesh Balani
Materials Science and Engineering (MSE)
Indian Institute of Technology, Kanpur- 208016
Email: [email protected], URL: home.iitk.ac.in/~anandh
http://home.iitk.ac.in/~anandh/E-book.htm
Incoherent Scattering (Compton modified) From loosely bound charges
 Incoherently scattered X-rays darken the background and are not useful from a XRD point
of view
 Here the particle picture of the electron & photon comes handy
E1  h  1
(  1 , 1 )
Electron knocked aside
2
E 2  h 2
(  2 , 2 )
    2   1  0 . 0243 (1  Cos 2 )
No fixed phase relation between the incident and scattered waves
Incoherent  does not contribute to diffraction
(Darkens the background of the diffraction patterns)
Fluorescent X-rays
 This signal is produced akin to the way the original X-ray beam was produced; just that
the input now is not electrons but X-rays
Knocked out electron
from inner shell
Vacuum
Energy
levels
E L3
L3
E L2
L2
E L1
L1
EK
K
Nucleus
Characteristic x-rays
(Fluorescent X-rays)
(10−16s later  seems like scattering!)