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www.reading.ac.uk/EMLab Transmission Electron Microscopy Peter Harris

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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

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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

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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.

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EM Workshops 2013 Transmission electron microscopy Specimens for TEM 3 mm TEM grid Carbon films

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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.

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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.

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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

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EM Workshops 2013 Biological TEM - negative staining Peptide fibrils, stained with methylamine tungstate (1%) on formvar/carbon grids. Marta Krysmann, School of Chemistry

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EM Workshops 2013 Biological TEM preparing specimens from tissue Microtome Fix dehydrate set in resin section deposit on grids stain

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EM Workshops 2013 Biological TEM thin section Kidney

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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

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EM Workshops 2013 Diffraction contrast Contrast in the TEM - 2

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EM Workshops 2013 Transmission electron microscopy TEM in physical science bright field imaging Dislocations in stainless steel foil Platinum/alumina catalyst

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EM Workshops 2013 Phase contrast: lattice imaging Contrast in the TEM - 3

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EM Workshops 2013 Multiple electron scattering Electrons passing through a crystal are multiply scattered

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EM Workshops 2013 Image simulations Example of image simulation: amphibole crystal

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EM Workshops 2013 EM Labs TEMs FEI/Philips CM20 Analytical TEM JEOL 2010 High resolution TEM

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EM Workshops 2013 New developments in TEM - 1 Ultra-high resolution TEM, with aberration correction, Tsukuba, Japan.

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EM Workshops 2013 New developments in TEM - 2 Tomography bringing the 3 rd dimension to TEM

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EM Workshops 2013 TEM at CfAM Carbon nanostructures

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EM Workshops 2013 TEM at CfAM Nanoporous Pt particles - applications in catalysis. Samina Akbar& Joanne Elliott, Department of Chemistry

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EM Workshops 2013 TEM at CfAM Micro-phase separated polymer particle, 120nm diameter. Hamley group.

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EM Workshops 2013 Becoming an EMLab user Sherrie Foo

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EM Workshops 2013 Remaining workshops DateTopic 20 November 2013 Environmental & Cryo SEM 27 November 2013 X-ray Analysis and Elemental Mapping

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EM Workshops 2013 Questions? Transmission electron microscopy Demo