Instrumentation: Transmission Electron · PDF fileAdvanced Instrumentation. light source...
Transcript of Instrumentation: Transmission Electron · PDF fileAdvanced Instrumentation. light source...
Contents:
1. Introduction
2. Sources
3. Lenses
4. Spectrometers and Filters
5. STEM
6. Advanced Instrumentation
light source
illumination system
imaging system
specimen
Basic functions of an optical microscopeH.J. Penkalla
Imagingsystem
specimen
Arrangement of the main components at the TEM
illuminationsystem
light (electron)source
H.J. Penkalla
plane wave
Transmissionfunction
Fourier-Transformation
Fourier-Transformation
Diffractionpattern
real image
HRTEM
Lens
P
CS = 0
Image plane
Aberration corrected electron optics
TU DarmstadtEMBL HeidelbergForschungszentrum Jülich
Volkswagen Stiftung
Haider, Rose, Urban et al. Nature 392, 768 (1998)
Example: SrTiO3, calculated images
Structuremodel
withoutcorrector
Cs-corrector,Cs = + 40 µm
Cs-corrector, Cs = - 40 µm, changes in oxygen sublattice
Jia, Lentzen, Urban, Science 299 (2003)
CsxNb2.54W2.46O14
Focal-series reconstruction of the object exit-plane wave function
Phase image = projected potential for thin object
Th. Weirich
J. Barthel, A. Thust (ER-C)
G. Cox, H. Hibst(BASF)
aa
bb
averaged phase image+ p2gg symmetry correction
projected crystal structure
CsxNb2.54W2.46O14
Th. Weirich, J. Barthel, A. Thust (ER-C), G. Cox, H. Hibst (BASF)
h ν
( 2 ) E k i n
( 1 ) E 0 - Δ E ,
D
= E B + E k i n
E 0
E Δ
Inelastic Scattering: Analytical Information
CondensorSystem(KöhlerIllumination)AnalyticalObjective Lens
First ProjectorSystem
Imaging½-Spectrometer
SecondProjectorSystem
ViewingChamber
ElectronDetectorand Camera
Energy SelectingSlit
EucentricGoniometer
Cathode
Energy Filter
Specimen
ImagingΩ−Spectrometer
Energy selectingslit