![]() ![]() This technology along with add on tools such as the Energy Dispersive X-Ray Analysis tool, or EDX, allows scientists to look at specimens at the atomic level, making species identification and elemental composition of a specimen precise. These images are similar to the bright-field images obtained using TEM. Both the SEM and the TEM have very high magnification and resolution, as I am sure you have seen in some of our previous posts. There are multiple detectors for STEM imaging: BF (bright-field) detector: small angles (<0-10 mrad). The TEM allows for some electrons to pass through the sample so that the scientist can look at different layers within the sample. The electrons from the beam of the SEM bounce off the sample creating backscatter electrons that are used to make an image in 3D. When using the SEM, the pedestal with the sample is coated with conductive material such as gold or graphite. The SEM and the Transmission Electron Microscope or TEM both use electrons, or negatively charged particles, to create an image. Additionally, it’s important to use the microscope in good working condition as this will reduce the quality of images that you receive. ![]() The image that is created from the scan is then transferred to a computer where the scientist can do further analysis. Several techniques can be employed to enhance the image quality of SEM, such as: fluorescence imaging, tip electron microscopy, multi-beam scanning and the use of colloidal crystals. ![]() The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. The confocal microscope uses a laser light that scans across the specimen. Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The size of the electron microscope chamber dictates the resulting sample’s size. The images of a tilt series are acquired over a wide range of viewing. Although the resolution is not great, the magnification allows a scientist to see down to the cell level. Using an SEM, you’re able to capture black-and-white 3D image samples that are either thick or thin. Electron tomography (ET) is a method for obtaining 3D-structural information using TEM. These microscopes use visible light to look at the specimen. The compound microscope and the dissection microscope are two of the most common. A new way of imaging frozen biological samples using electron microscopy is providing new glimpses into the nanoscopic world of cells. In the science world, there are a variety of different microscopes that use a handful of mechanisms. ![]()
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