X-rays Nature and origin of X-rays Interaction of X-rays with atoms.
-
date post
19-Dec-2015 -
Category
Documents
-
view
252 -
download
2
Transcript of X-rays Nature and origin of X-rays Interaction of X-rays with atoms.
X-rays
Nature and origin of X-rays
Interaction of X-rays with atoms
Energy Levels for a one electron atom
Energy levels for multielectron atoms
Ene
rgy
Sca
le (
log)
Electronic Transition to inner electron levels
Partial energy level diagram showing common transitions leading to X–radiation.
The most intense lines are indicated by the widest arrows
The orbital shells are labelled as K for n=1, L for n=2, M for n=3.
Some Experimental Data
Generation of X-Rays
Mo
e-
AccelleratingVoltage V
X-ray emission process
Inner shell ionization
Radiative de-excitation
Auger Emission
Auger electron emission following inner shell ionisation
Fluorescence Yield for K and L shells
Probability of a core hole in the K or L shell being filled by a radiative process
X-ray emission from a Silver targetIntensity
Characteristic Silver emission lines are over imposed on a continuous radiation background (Bremsstrahlung radiation) due to deceleration of high-energy electrons.
The three curves are in dependence from the electron accelerating voltage V
X–ray emission from a Mo and Cu target
X-ray absorption
€
I t = I0e−μ m ρx
It = incidentIo = transmitted X-ray intensitym = mass absorption coefficient (characteristic of the absorber)= density, andx = thickness of absorber.
X-ray absorption by lead
K
L
M
Absorption edges
Use of absorption edge as a filter to provide effectively monochromatic X-rays