The diagram of the electron microscope shows its complex internal components, including electron sources and electromagnetic lenses. There are two types of electron microscopes. The electron gun releases electrons that pass through multiple components and hit the gold-coated specimen. The diagram of an electron microscope with labels helps understand the various parts and their functions easily.
The well-labeled diagram of the electron microscope is given below:
Table of Content
What is Electron Microscope?
An electron microscope is a powerful tool used to visualize objects at extremely high magnifications. The diagram of electron microscopes shows the use of a particle beam of electrons to illuminate a specimen and create a highly magnified image. The formation of the image is achieved by using electromagnetic lenses to focus the electron beam onto a specific plane relative to the specimen.
Working Principle of Electron Microscope
Electron microscopes are designed to provide information about a sample’s structure, morphology, and composition by detecting signals that result from the interaction of an electron beam with the sample.
- The electron gun creates electrons.
- Two sets of condenser lenses concentrate the electron beam on the specimen and then into a slim, focused beam. To propel electrons along the column, an accelerating voltage (usually between 100 kV-1000 kV) is applied between the tungsten filament and the anode.
- The specimen being analyzed is exceptionally thin, at a thickness of at least 200 times less than that used in the optical microscope.
- The specimen holder is already equipped with ultra-thin sections measuring 20-100 nm.
- When the electronic beam passes through the specimen, electrons scatter in different directions, influenced by the specimen’s thickness or refractive index. The more electron-dense regions in the specimen scatter more electrons, resulting in a darker appearance in the image since fewer electrons reach that area of the screen. Conversely, transparent regions appear brighter.
- The electron beam emanating from the specimen travels to the objective lens, which boasts high magnification power and generates an intermediate magnified image.
- Subsequently, the ocular lenses produce the final, further magnified image.
Types of Electron Microscope
There are two primary types of electron microscopes, each with its own unique method of operation:
Transmission Electron Microscope (TEM)
The transmission electron microscope utilizes electron passage through thin specimens to generate a projection image. The Transmission Electron Microscope (TEM) has several similarities to the standard compound light microscope. Among its many uses, TEM is employed to image the internal structures of cells in thin sections, the configuration of protein molecules using metal shadowing, the organization of molecules in viruses and cytoskeletal filaments through negative staining, and the arrangement of protein molecules in cell membranes via freeze-fracture techniques.
Scanning Electron Microscope (SEM)
Scanning Electron Microscopy typically relies on the ejection of secondary electrons from a specimen’s surface. A scanning electron microscope, with its exceptional depth of focus, is analogous to a stereo light microscope in the field of electron microscopy. The scanning electron microscope (SEM) is a powerful tool that provides highly detailed images of cell surfaces and entire organisms that cannot be obtained through transmission electron microscopy (TEM).
Also, SEM is also used for particle counting and size determination, as well as process control. The SEM operates by scanning a focused electron beam over the specimen’s surface in a raster pattern, forming an image.
Parts of Electron Microscope
The Electron Microscope diagram shows that it comprises of a tall, vacuum-sealed column that is mounted vertically. It consists of the following components:
Electron gun
- The electron gun consists of a filament made of tungsten that is heated, thereby producing electrons.
Electromagnetic lenses
- The condenser lens directs the electron beam onto the specimen.
- A thin and tightly focused electron beam is created by the second condenser lens.
- The electron beam emitted by the specimen travels through the objective lens, a set of high-power magnetic coils, to produce an intermediate magnified image.
- The final, much-enlarged image is created by the projector (ocular) lenses, which are the third set of magnetic lenses.
- Each of these lenses functions as an image magnifier, retaining an amazing degree of detail and resolution.
Specimen Holder
- The specimen holder is comprised of a metal grid that secures an extremely thin film of carbon or collodion.
Image viewing and Recording System
- A fluorescent screen receives the final image projection.
- A camera for capturing the image is located beneath the fluorescent screen.
Conclusion – Diagram of Electron Microscope
Optical and electron microscopes are the two fundamental varieties of microscopes that we compare here. Unlike the optical microscope, which uses visible light to magnify images, the electron microscope uses a beam of electrons and their wave-like properties to magnify an object’s image. There are two types of electron microscope – SEM and TEM. The diagram of electron microscope helps us understand their structure clearly.
Also Read:
FAQs on Diagram of Electron Microscope
What is Electron Microscope Used for?
High resolution images of both biological and non-biological specimens including tissues, cells, organelles can be obtained using the electron microscopy (EM) technique which can be used to study f
What are the Three Electron Microscopes?
Electron microscopes can be classified into multiple types, such as transmission electron microscope (TEM), scanning electron microscope (SEM), and reflection electron microscope (REM).
Who Discovered the Electron Microscope?
The electron microscope is said to have been invented by German electrical engineer Ernst Ruska. The first commercially available, mass-produced electron microscope was created in 1931, and it was first made available for purchase in 1939.
What is the Structure of an Electron Microscope?
The electron microscope consists of a series of lenses including the condenser lens, second condenser lens, objective lens, and projector (ocular) lenses. These lenses work together to focus a thin electron beam onto the specimen and magnify the resulting image.
What are the Parts of a Microscope?
The parts of a microscope include the eyepiece, objective lenses, stage, light source, condenser, and focus knobs. Together, these components enable magnification and visualization of tiny objects with clarity.