What is an Electron Microscpe?

A group of microscopes that uses a beam of accelerated electrons as a source of radiation is called electron microscopes.

What is Electron Microscopy?

Electron microscopy (EM) is a technique for obtaining high-resolution images of biological and non-biological samples. Electron microscopy is used in biomedical research to examine the exact structure of tissues, cells, organs, and macromolecular complexes. The high resolution of electron microscope images is due to the use of electrons as radiation sources.

Electron Microscope Vs. Optical (Light) Microscope

Because the wavelength of an electron beam is 100,000 times shorter than the wavelength of visible light photons, electron microscopes have far greater detection power than light microscopes. These microscopes can provide a structural image of the smallest objects with a resolution better than 50 picometers. Electron microscopes have a magnification of more than 10 million times, while optical microscopes have a resolution of 200 nanometers and a magnification of less than 2000 times due to the limitation of the diffraction phenomenon.

What are the Types of Electron Microscopes?

Types of electron microscopes include four main types: Transmission Electron Microscope (TEM) Scanning Electron Microscope (SEM) Field Emission Scanning Electron Microscopy (FESEM) Reflection electron microscope (REM) Scanning tunneling microscopy (STM)

Scanning electron microscopy is based on the emission of secondary electrons. Due to the fact that the secondary electrons have low energy, they have a small mean free path in solid materials and move at the surface to a depth of a few nanometers.

A transmission electron microscope is used to look at thin specimens (tissue sections, molecules, etc.) through which electrons pass and produce an image. TEM is in many ways similar to a conventional light microscope. TEM is used to image intracellular space (in thin sections), the structure of protein molecules (using the Metal Shadowing technique), the structure of molecules in viruses and skeletal filaments, and the arrangement of protein molecules in cell membranes.

What are the Advantages of Electron Microscopes?

Exceptionally high magnification Extremely high resolution Provides investigation in a greater depth of field

What Is Plasma? | What Is Plasma Physics Good For?

Last updated on August 26th, 2023

Plasma Physics

Plasma is the fourth state of matter that can be reached in high energies. Normally, when atoms in a solid gain enough energy it goes to liquid phase, and then the phase transition is continued to the gas phase at higher energy levels, and then plasma is formed at extremely high temperatures. In a typical plasma, some or all of the electrons in an atom gain enough energy to overcome nucleus potential barrier and an ionized gas is formed. So, plasma contains free electron-ions and is able to conduct electricity. Since atoms are normally neutral, the plasma is electrically neutral. Plasma may contain magnetic fields as moving electric charges create them.

Plasma Temperature

Plasma is not condensed enough that its constituent particles collide with each other frequently, so energy transfer and thermal equilibrium in plasma is not the same as the gas phase. Applying electromagnetic fields to the plasma, it may go unstable and a bunch of very fast particles appear in it, hence the plasma can possess different temperatures in different parts at a time; as the temperature of sun’s corona – made of plasma – can reach to millions of degree, while the temperature of the surface of the sun is about thousands of degrees (Figure 1).

Plasma of the sun — Figure 1. Plasma of the Sun

Electromagnetic Interactions

Electromagnetic interactions are so important in the plasma as a result of electron-ion separation. Moreover, these interactions can occur at larger distances compared to the gas phase. So, waves in plasma, or organized motion of it, is very significant. Another noticeable feature of it is that it can be confined by using a magnetic field (Figure 2), a capability used in fusion energy research.

Figure 2. Utilizing Heated, Ionized Air to Stop Shock Wave of an Explosion

Plasma in the Universe

Plasma is the most abundant form of matter in the universe, as 99% of the seen universe is in the form of plasma. Stars, nebulas, and the aurora seen in the north and south pole are all made of plasma. We can also see it in everyday life in the form of a lightening, conductive gas in a fluorescent light bulb or a neon light bulb. In addition, it is a favorite field for the scientists to research.

NASA | Fiery Looping Rain on the Sun

What is Plasma Physics Used for?

Plasma has various applications in different fields, some of them are mentioned here:

Medical sciences
- Healing wounds
- Cancer therapy
- Improve bone healing
- Eliminating biological hazards
Cleaning the environment and surfaces (Plasma Cleaning)
Functionalizing different surfaces
- Making hydrophilic or hydrophobic surfaces (You can read more about them here: Hydrophilicity and Hydrophobicity)

Figure 3. Touching a Plasma Lamp, Electrons Tend to Discharge through the Body

Manufacturing computer chips
Plasma TV
Plasma lamp or globe
Nuclear energy reactors
Electron guns
Rocket propulsion
Plasma knife
…

Vac Coat Coating Systems

Vacuum coating systems made by Vac Coat Ltd. are optionally capable of performing the plasma surface cleaning process prior to the deposition. Some models which are equipped to the plasma cleaner option is magnetron sputter coater model DST1-300, desk sputter carbon coater equipped to turbo pump model DSCT, desk sputter carbon coater model DSCR, and triple target sputter coater model DST3 (You can read more about our magnetron sputter coaters here).

Sputter Coaters

DST1-300

DSCT

In DST1-300, the user is able to the sputtering deposition process in order to deposit the desired material after the plasma cleaning process, without having to break the vacuum or remove the sample from the vacuum condition. See the VacCoat Company website for more information.