MICROBEAM INSTRUMENTS SCANNING ELECTRON MICROSCOPY Equipment

JEOL 5800LV The Denver laboratory operates a JEOL 5800 LV scanning electron microscope. Low vacuum / low voltage electron microscopy is a new technology that provides the capability to view hydrated and uncoated samples and eliminates the need for sample preparation for many analyses. The digital 5800LV electron microscope with an energy dispersive x-ray analysis system provides the capability to image and chemically analyze a variety of samples including biological and geological materials, ceramics, polymers, composites, and metals. The instrument is equipped with a cryogenic stage system and a cathodoluminescence imaging system. Etec Autoscan, purchased in 1973; upgraded with an EDAX system in 1984. Capability-secondary electron and back scattered electron images to 40,000x. Energy dispersive x-ray detector for semi-quantitative analysis and mineral identification. Located in Reston. JEOL JSM-35C, purchased in 1978. Instrument is operational and not under a service contract. Secondary electron imaging only with output to Polaroid 4x5. JEOL JSM-840, integrated Princeton Gamma-Tech EDX, digital control system. Purchased in 1984, upgraded with LaB6 and ion pump in 1987; upgraded with Princeton Gamma-Tech system in 1993. Instrument capabilities: (1) As currently configured: The scanning electron microscope (SEM) was installed in 1984, upgraded in 1987 with a LaB6 emitter and ion pump, and in 1993 by the addition of a Princeton Gamma Tech energy dispersive detector and computer image digitizing and integration system. It represents an approach to a state-of-the-art digitizing SEM, capable of capturing images to computer memory and processing them with the PGT system. It is this capability which sets this instrument apart from traditional SEMs, and allows digital image editing and quantitative image analysis. The SEM is on the net, and the spectra and images can be easily FTP'd to in-house or remote computers. A high-resolution thermal printer allows instant reproduction at a considerable savings compared to traditional Polaroid. This device is run by a SUN workstation. Software is included that allow X-ray mapping, processing of images, semi-quantitative analysis, LAN connection, etc. The SEM has been fitted with a Princeton Gamma Tech energy dispersive X-ray detector (EDX) and is capable of quantitative x-ray spectral analysis as well as qualitative spectral identification. The EDX has a light element detector for the qualitative recognition of elements to boron. The EDX system is also capable of digitally controlling the SEM for X-ray elemental mapping. Traditional SEM images are acquired by detecting the emission of secondary electrons. The SEM also has the capability of detecting backscattered electrons (BSE) and electromagnetic radiation in the form of X-rays and normal light near the visible spectrum, i.e. cathodoluminescence (CL). The instrument has been upgraded with the install of a LaB6 crystal emitter and ion pump, which has the advantage of high current density at lower voltage (a brighter beam). What sets this instrument apart from the electron microprobe (EPMA) are the degrees of freedom the operator has with instrumental parameters such as acceleration voltage, beam current, final apertures and specimen manipulation, which includes working distances between 5 and 48 mm, 350 degrees of rotation and 90 degrees of tilt. The fact the operator is unconstrained allows for the same creativity we all attribute to photographic artists. The freedoms allowed within the specimen chamber implies almost anything can be photographed with the resolving power attributable to electron beam instruments. (2) possible or planned capability: Shape analysis and quantitative modal and shape image processing. The Microanalysis Laboratory is located in Reston. Cambridge Stereoscan 100, purchased in 1985, upgraded to digital capability in 1994. Secondary electron imaging with output to Polaroid 4x5 film or digital format. Instrument is principally dedicated to examination and illustration of microfossils. JEOL JSM-6400 digital scanning electron microscope with Kevex Delta X-ray Image Analysis system and LeMont Image Analyzer DA 10. Purchased in 1985, upgraded in 1992 and 1993. The SEM equipment includes a light-element (to carbon) energy-dispersive X-ray spectrometer system and a particle feature analyzer (grain-size and morphochemical analysis). The laboratory is fully equipped for high-resolution micrography, qualitative/quantitative x-ray microanalysis, and particle grain-size/morphochemical analysis. Computerized morphochemical analysis of fine-grained sediments measures particle size, shape, and chemistry of all particles in a field of view and reports the results in tables, histograms, or x-y plots as particle size and shape statistics per user-defined chemical composition. The digital archiving system provides a data link over the computer network to allow investigators at remote sites to access images and x-ray data within minutes of collection. Located at Woods Hole.

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URL http://geology.cr.usgs.gov/capabilities/chema/microinst/sem/equip.html