Electron Microscopy: Instrumentation, History, and Applications PDF

MICROSCOPY IN THE NEW WORLD UN YEAR OF MICROSCOPY 2031 To recognized the contribution of Ernst Ruska in the advancement of Microscopy ELECTRON MICROSCOPE 1920 - FOUND THAT ACCELERATION OF ELECTRON IN VACUUM HAS THE SAME CHARACTERISTIC AS LIGHT IMPORTANT CHARACTERISITIC OF ELECTRON T...

MICROSCOPY IN THE NEW WORLD UN YEAR OF MICROSCOPY 2031 To recognized the contribution of Ernst Ruska in the advancement of Microscopy ELECTRON MICROSCOPE 1920 - FOUND THAT ACCELERATION OF ELECTRON IN VACUUM HAS THE SAME CHARACTERISTIC AS LIGHT IMPORTANT CHARACTERISITIC OF ELECTRON TRAVELS IN STRAIGHT LINE HAVE A WAVELEGTH OF 100000 X SMALLER THAN LIGHT ELECTRIC POWER & ELECTROMAGNETIC WAVES HAVE EFFECT ON THE ELECTRONS Light vs Electron Microscope Instrumentation & Techniques IT-1. Electron optics and optical elements IT-2. High resolution TEM and STEM IT-3. Super-resolution light microscopy and nanoscopy imaging IT-4. Scanning electron microscopy IT-5. Analytical electron microscopy IT-6. Environmental electron microscopy IT-7. In-situ microscopic techniques and cryo-microscopy IT-8. Ultrafast microscopies IT-9. Electron diffraction techniques IT-10. Electron tomography IT-11. Electron holography and lens-less imaging IT-12. Surface microscopy and spectroscopy IT-13. Focused ion beam microscopy and techniques IT-14. Scanning probe microscopy and near-field microscopies IT-15. X-ray, neutron and other microscopies IT-16. Electron microscopy theory and simulations IT-17. Atom probe and non-traditional microanalytical tasks Materials Science MS-1. Nanoobjects and engineered nanostructures, catalytic materials MS-2. Carbon-based nanomaterials, nanotubes, fullerenes, graphenes MS-3. Thin films, coatings and surfaces MS-4. Metals, alloys and metal matrix composites MS-5. Ceramics and inorganic materials MS-6. Polymers and organic materials MS-7. Composite materials and hybrids MS-8. Semiconductors and materials for information technologies MS-9. Defects in materials and phase transformations MS-10. Porous and architectured materials MS-11. Amorphous and disordered materials, liquid crystals, quasicrystals MS-12. Magnetic, superconducting, ferroelectric and multiferroic materials MS-13. Materials in geology, mineralogy and archeology MS-14. Energy-related materials Life Sciences LS-1. Live imaging of cells, tissues and organs LS-2. Structure and function of cells and organelles LS-3. High-resolution localization of molecular targets and macromolecular complexes LS-4. Structure of macromolecules and macromolecular assemblies LS-5. Cellular transport and dynamics LS-6. Microbiology and virology LS-7. Invertebrates and parasitology LS-8. Plant science and mycology LS-9. Genetically-modified organisms and animal science LS-10. Human health and disease LS-11. Physiology and pathology LS-12. Advances in immunohistochemistry and cytochemistry LS-13. Embryology and development biology LS-14. Neuroscience Interdisciplinary ID-1. Correlative microscopy in life and material sciences ID-2. Imaging mass spectrometry ID-3. Microscopy of single molecule dynamics ID-4. High-throughput microscopy and its applications ID-5. Nanoparticles: Applications and bio-safety issues ID-6. Forensic science ID-7. Arts, restoration and archeology ID-8. Three-dimensional reconstructions ID-9. Microscopic image analysis and stereology ID-10. Advances in sample preparation techniques ID-11. Multidisciplinary applications of progressive light microscopy imaging techniques ID-12. In situ and environmental microscopy of material reactions and processes ID-13. Materials for medicine and biomaterials HISTORY OF EM 1931 ERNST RUSKA ( 1986 NOBEL PRIZE FOR PHYSICS) – THE FIRST TEM – 2 ELECTROMAGNETIC LENS HISTORY OF EM IN MALAYSIA 1ST EM IN MALAYSIA UNIVERSITI MALAYA (1969) DEPT. OF PATHOLOGY UNIVERSITI KEBANGSAAN MALAYSIA (1980) Bombardment of electron on the specimen causes 1. e to be absorbed by the specimen (thickness & composition of the specimen) 2. e diffracted at a small angle depending on the composition of the specimen. Bombardment of electron on the specimen causes 1. e to be absorbed by the specimen (thickness & composition of the specimen) 2. e diffracted at a small angle depending on the composition of the specimen.  3) e diffraction in a specific pattern/direction (in crystal specimen – crystal structure 4) Backscattered electron  5) secondary e - e colliding with the specimen releasing the electron 6) e causing the specimen to produce X- ray Peak show the energy level and wavelength in relation to the elemental composition of the specimen  7) e causes the specimen to produce photons - cathodluminescen 8) e energy loss due to interaction with the specimen and detected with EELS (Energy Loss Spectrometry)  TRANSMISSION ELECTRON MICROSCOPE TEM 4 MAIN COMPONENTS 1. ELECTRON OPTIC COLUMN 2. VACUUM SYSTEM 3. LENSES & ELECTROMAGNETIC WAVES 4. CONTROL PANEL ELECTRON GUN 1. FILAMENT 2. WELHNELT CYLINDER 3. ANODE FILAMEN 1. TUNGSTEN 2. LaB6 (LANTHANUM HEXABORIDE) 3. FEG (FIELD EMISSION GUN) TUNGSTEN FILAMENT (W) SOURCE THAT EMIT ELECTRONS 2 STRONGER ELECTRON SOURCE - LaB6 & FEG LaB6 - 10X MORE ELECTRONS AS COMPARED TO W FEG - 1000X MORE ELECTRONS AS COMPARED TO W VACUUM SYSTEM THE PROPERTIES OF ELECTRON AS LIGHT IF MANIPULATED IN VACUUM. THE WHOLE COLUMN FROM THE ELECTRON GUN TO THE FLUORESCENT SCREEN (INCLUDING THE CAMERA) IS UNDER VACUUM DIFFERENT VACUUM STATUS VACUUM IS HIGH AT THE 1. SPECIMEN SECTION 2. ELECTRON GUN - VACUUM ACHIEVE USING ION GETTER PUMP LOWER VACUUM 1. PROJECTION AREA 2. CAMERA ACHIEVED USING OIL DIFFUSION PUMP  At this pressure, the gas molecule / liter = 7 X 1012 and the chances of an electron colliding with a gas molecule during the acceleration in the column is almost 0. Electron will acclerate from the electron gun to the specimen in the column without disturbance. ELECTROMAGNETIC LENSES Same function as glass lens (LM) When electrical energy is applied through the circuit, electronmagnetic pressure can be detected. By changing the electrical energy to the circuit coil, magnification can be obtained. Abberation 1. spherical aberration Magnification at the centre of the lens differ from the magnification at the edge of the lens. Chromatic aberration Magnification of the lens is directly proportional to the wavelength of the electron - reduce due to stable accelerating voltage and very thin specimen Astigmatism Circle in a specimen appeared as oval in the image formed. Corrected using variable electromagnetic coil TEM have 5 lenses CONDENSOR LENS OBJECTIVE LENS DIFFRACTION LENS PROJECTION LENS LENS REQUIREMENT HIGH STABILITY HIGH MAGNIFICATION TEM LENSES NEED TO BE WATER-COOLED CONDENSOR LENS FOCUS THE ELECTRON BEAM ON THE SPECIMEN ELECTRON BEAM GENERATED FROM THE ELECTRON GUN IS COORDINATED IN SUCH A WAY THAT THE ELECTRON BEAM IS PARALLEL TO THE SPECIMEN OBJECTIVE LENS TO PRODUCE AN ENLARGED IMAGE OF THE SPECIMEN PROJECTION LENS TO PRODUCE AN ENLARGED IMAGE THAT IS ENLARGED BY THE OTHER LENSES AND PROJECTED ONTO THE FLUORESCENT SCREEN. CONTROL PANEL - OBSERVATION AND RECORDING OF IMAGES IMAGES ON THE FLUORESCENT SCREEN CAN BE OBSERVED THROUGH THE WINDOW ON THE PROJECTION AREA. PERMANENT IMAGE CAN BE RECORDED IN 1. PHOTOGRAPHY 2. VIDEOPRINT 3. COMPUTER  For high resolution - Accelerating voltage and current through the lens system must be very stable.  Control knob are replaced by microprocessor & digital system. SCANNING ELECTRON MICROSCOPE (SEM) 1935 MAX KNOLL 1937 MANFRED VON ARDENNE 1942 ZWORYKIN, HILLIER & SNIJDER RESOLUTION = 50 NM, MAGNIFICATION: 8000X 1998 RESOLUTION = 1 NM, MAGNIFICATION : 400 000X 2008 Resolution = 0.1 nm, Magnification: 600 000X  SEM (SCANNING ELECTRON MICROSCOPE) 4 MAIN COMPONENTS 1. ELECTRON OPTIC COLUMN 2. VACUUM SYSTEM 3. LENSES 4. CRT SCANNING DIFFRACTION/REFLECTED SECONDARY ELECTRON BACKSCATTERED ELECTRON (BSE) ELECTRON GUN Is a device that emits electron from the source (metal) and accelerates them in a strong electric field ELECTRON GUN 1. FILAMENT 2. SELINDER WEHNELT CYLINDER 3. ANODE FILAMENT 1. TUNGSTEN 2. LaB6 (LANTHANUM HEXABORIDE) 3. FEG (FIELD EMISSION GUN) VACUUM SYSTEM ELECTRON BEHAVE AS LIGHT IF MANIPULATED IN VACUUM. The whole column from the electron gun to the sample are in vacuum Evacuates the column and specimen chamber to a high vacuum level (10 -4 to 10 -9 Pa). ELECTRONMAGNETIC LENSES 3 LENSES CONDENSOR LENS used to converge electron beam emitted from the electron gun into a fine beam OBJECTIVE LENS Used to converge electron beam into a fine beam and focus it on the sample surface. APPLICATION 7 SAMPLE PREPARATION APPLICATION TO GET INFORMATION ON THE SURFACE MORPHOLOGY OF THE SPECIMEN SAMPLE PREPARATION REQUIRED DEHYDRATION  COATING OF THE SPECIMEN - GOLD/OTHER HEAVY METALS CONTROL PANEL - OBSERVATION & RECORDING OF IMAGES PERMANENT IMAGES ARE RECORDED USING 1. PHOTOGRAPHY 2. VIDEOPRINT 3. KOMPUTER CATEGORIES OF NEW SEM LOW VOLTAGE SEM Does not require coating and specimen is not charge up. Usage of low voltage From 0.1 kV to 10 kV. SCANNING TRANSMISSION EM (STEM) Hybrid of TEM-SEM or SEM-TEM Specimen must be ultra thin ( 60 nm to 120 nm). TEM – Image is formed from e that is transmitted and collected. SEM – Image formed from SE & BSE SEM WITH EDX ELECTRON BOMBARDMENT PRODUCES X-RAY THAT CAN BE DETECTED USING EDX ATAU WDX. LINE INTENSITY IS DIRECTLY PROPORTIONAL TO THE CONCENTRATION OF THE ELEMENTAL COMPONENT. ENVIRONMENTAL SCANNING ELECTRON MICROSCOPE (ESEM) - DOES NOT REQUIRED SAMPLE PROCESSING - DOES NOT REQUIRED COATING F THE SAMPLE. - CAN BE USED TO SCAN WET OR LIVE SPECIMEN