www.reading.ac.uk/EMLab Transmission Electron Microscopy Peter
Harris
Slide 2
EM Workshops 2013 Transmission electron microscopy What is
transmission electron microscopy? TEM in biological science CfAMs
TEMs TEM in physical science Recent developments in TEM
Slide 3
EM Workshops 2013 SEM & TEM Scanning electron microscope
Electron gun Specimen Electron gun Condenser lens Objective lens
Specimen Projector lens Fluorescent screen Electron gun Digital
camera Condenser lens Objective lens Specimen Projector lens
Fluorescent screen Electron gun Digital camera Transmission
electron microscope
Slide 4
EM Workshops 2013 Transmission electron microscopy
Electromagnetic lenses A current through the coils creates a
magnetic field, symbolized by red lines in the diagram on the left.
Electrons close to the centre are less strongly deflected than
those passing through the lens far from the axis. Electron gun
Current passed through LaB 6 crystal causes electrons to be
emitted. Anode accelerates electrons to 80 kV 200kV.
Slide 5
EM Workshops 2013 Transmission electron microscopy Specimens
for TEM 3 mm TEM grid Carbon films
Slide 6
EM Workshops 2013 Absorption contrast: Heavy atoms absorb more
electrons than light atoms. Contrast in the TEM - 1 Biological and
soft matter Scattering contrast: Some electrons blocked by
objective aperture.
Slide 7
EM Workshops 2013 Positive staining Electron-dense heavy metal
salt selectively stains certain features within the sample. Block
copolymer containing polystyrene and polymethylmethacrylate stained
with ruthenium tetroxide.
Slide 8
EM Workshops 2013 Biological TEM - negative staining
Surrounding biomolecules with thin amorphous layer of heavy metal
salt. Reveals structure, and reduces structural flattening that
occurs in the absence of stain. Commonly used stains: uranyl
acetate, uranyl formate, sodium/potassium phosphotungstate,
ammonium molybdate. Adenovirus negatively stained with uranyl
acetate
Slide 9
EM Workshops 2013 Biological TEM - negative staining Peptide
fibrils, stained with methylamine tungstate (1%) on formvar/carbon
grids. Marta Krysmann, School of Chemistry
Slide 10
EM Workshops 2013 Biological TEM preparing specimens from
tissue Microtome Fix dehydrate set in resin section deposit on
grids stain
Slide 11
EM Workshops 2013 Biological TEM thin section Kidney
Slide 12
EM Workshops 2013 The transmission electron microscope is not
just a microscope! Diffraction pattern (crystalline C 60 ) Energy
dispersive X-ray spectrum X-ray analysis workshop: November 27
Slide 13
EM Workshops 2013 Diffraction contrast Contrast in the TEM -
2
Slide 14
EM Workshops 2013 Transmission electron microscopy TEM in
physical science bright field imaging Dislocations in stainless
steel foil Platinum/alumina catalyst
Slide 15
EM Workshops 2013 Phase contrast: lattice imaging Contrast in
the TEM - 3
Slide 16
EM Workshops 2013 Multiple electron scattering Electrons
passing through a crystal are multiply scattered
Slide 17
EM Workshops 2013 Image simulations Example of image
simulation: amphibole crystal
Slide 18
EM Workshops 2013 EM Labs TEMs FEI/Philips CM20 Analytical TEM
JEOL 2010 High resolution TEM
Slide 19
EM Workshops 2013 New developments in TEM - 1 Ultra-high
resolution TEM, with aberration correction, Tsukuba, Japan.
Slide 20
EM Workshops 2013 New developments in TEM - 2 Tomography
bringing the 3 rd dimension to TEM
Slide 21
EM Workshops 2013 TEM at CfAM Carbon nanostructures
Slide 22
EM Workshops 2013 TEM at CfAM Nanoporous Pt particles -
applications in catalysis. Samina Akbar& Joanne Elliott,
Department of Chemistry
Slide 23
EM Workshops 2013 TEM at CfAM Micro-phase separated polymer
particle, 120nm diameter. Hamley group.
Slide 24
EM Workshops 2013 Becoming an EMLab user Sherrie Foo
Slide 25
EM Workshops 2013 Remaining workshops DateTopic 20 November
2013 Environmental & Cryo SEM 27 November 2013 X-ray Analysis
and Elemental Mapping
Slide 26
EM Workshops 2013 Questions? Transmission electron microscopy
Demo