Report about TEM & SEM
Biology Report About TEM & SEM
There are two types of electron microscopes, a Transmission electron microscope (TEM) and a scanning electron microscope (SEM), which both work in different .ways, at different magnifications/
In a transmission electron microscope, the electron beam passes through a very thin prepared sample. The electrons pass through the denser parts of the sample less easily, which gives some contrast. The final image produced from a TEM is two-dimensional. The magnification possible with a TEM is times 500,000.
With a Scanning electron microscope, the electron beam is directed onto a sample and unlike the TEM, the electrons do not pass through the specimen. Instead they are ‘bounced off’ the sample. Another difference between a TEM and a SEM is that the final image produced in a SEM, Is a 3D view of the surface of the sample, rather than 2D, like an image from a TEM.
There are several advantages of using the electron microscope. One example is that the resolution is 0.2nm, which is 1000x more than in the light microscope. Because of this, the electron microscope can be used to produce detailed images of the structures and organelles within cells. In addition the SEM produces 3D images that can reveal the detail of contours and cellular or tissue arrangements, which is not possible to do using a light microscope.
On the contrary there are also some limitations of the electron microscope. For example the electron beams are deflected by the molecules in air, so samples have to be placed in a vacuum. In addition electron microscopes are extremely expensive items. Also preparing samples and using an electron microscope both require a high degree of skill and training.
Light microscopes have a low resolution which means that if the magnification is above x1500, the image is not clear. This is where electron microscopes come in particularly useful. Electron microscopes can distinguish between objects o.2nm apart. The resolution of an electron
There are two types of electron microscopes, a Transmission electron microscope (TEM) and a scanning electron microscope (SEM), which both work in different .ways, at different magnifications/
In a transmission electron microscope, the electron beam passes through a very thin prepared sample. The electrons pass through the denser parts of the sample less easily, which gives some contrast. The final image produced from a TEM is two-dimensional. The magnification possible with a TEM is times 500,000.
With a Scanning electron microscope, the electron beam is directed onto a sample and unlike the TEM, the electrons do not pass through the specimen. Instead they are ‘bounced off’ the sample. Another difference between a TEM and a SEM is that the final image produced in a SEM, Is a 3D view of the surface of the sample, rather than 2D, like an image from a TEM.
There are several advantages of using the electron microscope. One example is that the resolution is 0.2nm, which is 1000x more than in the light microscope. Because of this, the electron microscope can be used to produce detailed images of the structures and organelles within cells. In addition the SEM produces 3D images that can reveal the detail of contours and cellular or tissue arrangements, which is not possible to do using a light microscope.
On the contrary there are also some limitations of the electron microscope. For example the electron beams are deflected by the molecules in air, so samples have to be placed in a vacuum. In addition electron microscopes are extremely expensive items. Also preparing samples and using an electron microscope both require a high degree of skill and training.
Light microscopes have a low resolution which means that if the magnification is above x1500, the image is not clear. This is where electron microscopes come in particularly useful. Electron microscopes can distinguish between objects o.2nm apart. The resolution of an electron