SEM: What is Desktop Scanning Electron Microscopy?
Scanning electron microscopy (SEM) is an innovative technique used to evaluate the surface topography and chemistry of samples with exceptional resolution. Historically, microscopic interrogation of samples was carried out using an optical microscope, which enabled analysts to magnify samples up to 1000x. This maximum resolving power is determined by the diffraction limit of visible light, which means it is impossible to resolve two points on a surface that are within 200 nanometres (nm) of one another. Characterizing the nanoscale topographical features and identifying trace level elements in the uppermost layers of a sample is subsequently extremely difficult, if not impossible, with optical microscopy.
In this blog post, Particulate Systems explores the working principles and applications of SEM in greater depth.
Working Principles of SEM
While conventional microscopy uses a light source and an array of lenses to illuminate and observe samples with good degrees of magnification, SEM uses an electron beam and a series of photodetectors to scan surfaces and generate three-dimensional topographical surface maps with a resolving power in the nanometres
The electron beam is generated using a high-brightness electron source and a series of sequential lenses and apertures. This beam then passes through deflector coils which continuously alter the position of the beam, causing it to scan the sample in a raster pattern. Backscattered electrons (BSE), secondary electrons (SE), and x-rays are generated as the electron beam impacts the surface. These signals are unique to sample chemistry and topography.
X-ray, BSE, and SE detectors in the sample chamber obtain and use these signals to generate topographical and morphological images of samples with nanoscale resolution.
Benefits of Desktop SEM
There are numerous benefits of SEM, the foremost of which is its unmatched resolving power. The Phenom desktop scanning electron microscope from Particulate Systems boasts outstanding imaging power with magnifications of up to 1,000,000x and resolution as low as 1nm. Meticulously engineered from the ground up, the Phenom desktop SEM was designed to rival the performance of the large, expensive floor models at the price and size of a desktop.
Benchtop SEM tools are also designed with modern users in mind, providing both precision and speed for complex high throughput analysis. They significantly reduce the margin for human error with intuitive software systems capable of helping users extract the maximum amount of information from computer-generated imagery. With the most intuitive and easy-to-use controls available, the Phenom range boasts the fastest time from sample loading to SEM image acquisition on the market. In under 30 seconds, users can load and scan samples with full degrees of magnification thanks to integrated X, Y positioning equipment and a simple user interface.
SEM has subsequently proved instrumental in modern biochemistry and life sciences applications, materials characterization, all-around forensic analyses, and quality assurance and control.
SEM Tools from Particulate Systems
Particulate Systems is a division of Micromeritics focused exclusively on the commercialization of high-technology solutions for particle analysis and materials characterization. We offer a suite of SEM instruments suitable for academic- and industrial-scale sample analysis, providing the framework for you to acquire new levels of information about your samples and products.Posted on