SEMtutkimuksilla

SEMtutkimuksilla refers to research conducted using a scanning electron microscope (SEM). A scanning electron microscope is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. As the electrons interact with the atoms in the sample, they generate various signals that can be detected and assembled to form an image. SEMs are widely used in a variety of fields, including materials science, biology, geology, and forensic science, due to their ability to provide high-resolution images of sample surfaces with a large depth of field.

The process involves bombarding the sample surface with an electron beam. This interaction causes secondary electrons, backscattered electrons, and X-rays to be emitted from the sample. Detectors capture these emitted signals, and a computer translates them into a digital image. Different detectors can be used to highlight specific characteristics of the sample. For instance, secondary electron detectors are sensitive to surface topography, while backscattered electron detectors are sensitive to atomic number contrast, revealing variations in elemental composition. Energy-dispersive X-ray spectroscopy (EDX or EDS) can be coupled with SEM to provide elemental analysis of the sample at specific points or across an area.

SEMtutkimuksilla allows for the examination of samples at magnifications ranging from around 10x to over 100,000x, with resolutions typically in the nanometer range. This makes it an invaluable tool for observing microstructures, surface morphology, and the distribution of elements within a sample. Applications include characterizing the fracture surfaces of materials, studying the morphology of biological specimens, analyzing archaeological artifacts, and identifying contaminants. The sample preparation for SEM can vary depending on the material, but often involves coating non-conductive samples with a thin layer of conductive material like gold or carbon to prevent charging under the electron beam.