Microscopy: Advancements and Types

Study Notes

Microscopy in the New World

Microscopy has advanced significantly, with contributions from scientists like Ernst Ruska.
The UN Year of Microscopy 2031 recognizes these advancements.

Electron Microscope

In 1920, it was discovered that accelerating electrons in a vacuum has similar properties to light.
Electrons travel in straight lines.
The wavelength of electrons is significantly smaller than light (100,000 times smaller).
Electromagnetic waves and electric fields affect electrons.

Different Types of Microscopy

Light Microscopy (LM): The diagram illustrates the path of light through a specimen, objective lens, projector lens, and to the viewer's eye.
Transmission Electron Microscopy (TEM): The diagram illustrates the path of electrons through an illumination source, condenser lens, specimen, objective lens, and final lens to create an image on a phosphorescent screen.
Scanning Electron Microscopy (SEM): The diagram illustrates the path of electrons emitted from an illumination source, condenser lens, specimen, final lens, to the signal detector, creating an image.

Instrumentation and Techniques

Various techniques and instrumentation are discussed, including electron optics, high-resolution TEM, super-resolution light microscopy, scanning electron microscopy, analytical electron microscopy, environmental electron microscopy, and more.

Materials Science

Materials science applications discussed include nanoobjects, engineered nanostructures, catalytic materials, carbon-based nanomaterials, thin films, metallic alloys, ceramics, polymers, composite materials, semiconductors, defects in materials, porous materials, magnetic materials, minerals, and energy-related materials.

Life Sciences

Life sciences applications discussed include live imaging of cells, tissues, and organs; structure and function of cells, molecular targets, cellular transport; microbiology, virology, invertebrates, parasites, plant science, mycology, genetically-modified organisms, animal science, human health, physiology, pathology, immunohistochemistry, cytochemistry, embryology, and neuroscience.

Interdisciplinary Studies

Interdisciplinary research in microscopy encompasses correlative microscopy in both life and material sciences, imaging mass spectrometry, single molecule dynamics, microscopy of nanoparticles, and bio-safety issues. These studies cover areas such as forensic sciences, arts restoration and archeological studies, three-dimensional reconstructions, microscopic image analysis, and advanced sample preparation techniques. Multidisciplinary applications of progressive light microscopy imaging techniques, in situ and environmental microscopy of material reactions and processes, and materials in medicine and biomaterials are also highlighted.

History of EM

Ernst Ruska received the 1986 Nobel Prize in Physics for his work in microscopy.
The first TEM (transmission electron microscope) used two electromagnetic lenses.
Details about the first EM in Malaysia and its location are provided.

Microscopy for the Future

Transmission Electron Microscopes (TEM): The diagram demonstrates the mechanism of a TEM.
Scanning Electron Microscopes (SEM): The diagram demonstrates the mechanism of a SEM.
Key characteristics of the SEM and TEM are tabulated.
Causes of electron bombardment on the specimen include absorption, diffraction at small angles, and diffraction patterns.
Various processes of electron interaction with the sample, such as generating secondary electrons, X-rays, and producing photons through cathodluminescence, are detailed.
The four main components of TEM and SEM are described.
The components of an electron gun, including tungsten filament, Lanthanum hexaboride (LaB6), and Field emission gun (FEG), are identified.
Characteristics of different types of filaments are highlighted, including their strengths and weaknesses.
The vacuum system's importance in maintaining a stable electron path through the column is explained using different vacuum states.
The role of electromagnetic lenses and their impact on magnification are discussed.
TEM lens aberration (spherical aberration, chromatic aberration, and astigmatism) is discussed and explained.
Components of a TEM, including condenser lens, objective lens, diffraction lens, projection lens, and their functions are outlined, including their cooling needs.
Control panel functions, such as image observation and recording methods (photography, videoprinting, and computers), are detailed.
High-resolution TEMs require stable accelerating voltages and currents.
Modern control panel systems use digital systems and microprocessors for improved functionality.
The diagram demonstrates the interactions of electrons with a sample in either a TEM or SEM setting.
Information on electron microscopy applications and sample preparation are presented, including sample coating, dehydration, and low voltage SEM techniques.
Details of Scanning Transmission EM (STEM) types of microscope and their specifications are highlighted.
Analysis techniques, such as energy-dispersive X-ray spectroscopy (EDS), are outlined.
Environment Scanning Electron Microscopes (ESEM) use for analysis of wet samples are detailed.