By Ebatco
Ebatco NAT Lab has a state-of-the-art low vacuum scanning electron microscope (SEM) in its nano analytical tool set. The JEOL 6610LV can produce high resolution images under either secondary electron mode or a backscattered electron mode for surface topography and composition analysis. The SEM is expected to further expand NAT Lab's portfolio offerings in surface morphology, metallurgy, particle sizing, surface roughness and micro/nano dimensional measurement areas. In principle, the SEM generates a primary focused electron beam in a vacuum chamber and raster scans the beam over a sample surface. The incident primary electrons interact with the atoms in the surface of the sample. Some of the primary electrons excite the sample to emit secondary electrons while some are being scattered back. A secondary electron detector or a backscattered electron detector collects and converts the secondary electrons or the back scattered electrons into high resolution images. Secondary electrons are emitted by atoms near the surface of a sample material when their electrons become excited and have sufficient energy to escape the sample surface. Secondary electrons carry information about morphology and surface topography of the sample. The contrast is dominated by the so-called edge effect: more secondary electron can leave the sample at edges for reduced material retardation and adsorption and thus can lead to increased brightness. A highly sensitive backscatter electron detector captures composition, topography, and shadow images. Elements of higher atomic number will backscatter electrons more strongly than those of lower atomic numbers. Backscatter imaging allows for improved image contrast for compositional images as well as topographical images. Therefore, backscatter detectors are used to detect areas of varying chemical compositions. Backscattered electron imaging of nonconductive, uncoated samples shows composition by contrast; higher atomic number regions are brighter, while lower atomic number regions are darker. The most advantageous features of the JEOL 6610LV SEM are the low voltage and low vacuum operation capabilities. The low voltage operation has the advantage of reducing the interaction volume within the specimen, thus increasing the surface specificity of the technique. It gives greater visibility of surface marks, ultra-thin film and contaminations. By operation at low voltage, the charge buildup on non-conductive surface can be minimized or eliminated. It allows high resolution imaging of non-conductive samples without pretreatment. This feature is particularly useful for samples whose surface can't be changed or modified, such as museum, forensic and biological samples. The low-vacuum (LV) capability allows for viewing the samples which are wet, oily, outgas excessively. It could be used for freeze-dried samples of hydrated surface with basic structural integrity. The low-vacuum operation capability is also great for working with nonconductive materials by eliminating electric charge built up on non-conductive sample surfaces through chamber gas ionization. With appropriate combination of voltage and vacuum, the JEOL 6610LV has versatility and high resolution across the magnification range of 5x-300,000x, delivering amazing clarity, revealing the finest structures of conducting, non-conducting and biological samples. This JEOL 6610LV SEM is equipped with a large specimen chamber that allows for analysis of a wide variety of samples with sizes and shapes up to 80 mm in height and 200 mm in diameter. Besides, the SEM is also equipped with a convenient eucentric 5-axis motorized stage with automatic tilt and rotation. This stage is very useful for keeping the area of interest in the field of view, particularly for analyzing areas that are offset from the point of rotation. Grating calibration grid imaged in secondary electron mode Typical Experimental Results Failure Analysis: upper row, cross-section of a fractured copper wire; lower row, cross-section of a fractured steel wire Pollen samples imaged without conductive coating: left, yellow sweet clover imaged at 2.5kV; right: goldenrod imaged at low vacuum 110Pa Coral surface imaged without conductive coating at high voltage (30kV, left) and low voltage (1.5kV, right) Fresh Goldenrod flower imaged without conductive coating: petals (left, 30 Pa); pollens on stigma (right, 70Pa) Zinc oxide particles with sub-micron particle sizes Gold particles imaged at 300,000x showing the nano meter resolution of the SEM Applications Alloys and Metals Biofilms Biological Samples Ceramics Chemical Etching Chemical Imaging Cleaning Problems Contamination and Stain Investigation Corrosion Analysis Cross-section Analysis Failure Analysis Feature Imaging Feature Measurement Fiber Characterization Foreign Material Identification Forensic Analysis Fractography Fracture Characterization Freeze Drying Samples Geochemical Analysis Geological Samples Glasses Grains and Grain Boundaries High Resolution Imaging IC Failure Analysis Iron and Steel Material Identification Medical Devices Metallographic Analysis Metallurgy Micrographs Microstructure Evaluation Nano Materials Nano Particles Particle Sizing Phase Identification Plastic Deformation Plastics and Polymers Scratch and Scuffing Surface Defect Analysis Thin Films and Coatings Tribological Surfaces Wear Mechanisms Wear Surfaces Welds Instrument: JEOL 6610 LV Scanning Electron Microscope Instrument Key Specifications Filament W hairpin filament Resolution High Vacuum: 3nm (30kV), 8nm (3kV), 15nm (1kV) Low Vacuum: 4 nm (30kV) Accelerating Voltage 300 V to 30 kV Magnification 5x to 300,000x LV Detector Multi-segment BSED LV Pressure 10 to 270 Pa Sample Sizes Height: 80mm; Width: 178 mm Stage Eucentric 5 axis motor control, asynchronous movement, x-y: 125mm-110mm, z: 5mm-8mm, tilt:-10 to 90 degrees, rotation: 360 degrees Resolution 5120 x 3840 pixels Condenser Lens Zoom condenser lens Objective Lens Conical objective lens
