Instrumentation
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The equipment in our laboratory includes sample preparation equipment, such as optical microscopes, clean benches, polishing and sawing equipment, balances, ovens, ultrasonic cleaner, evaporators, microbalances, clean room with micromanipulators and a meteorite processing lab. In addition, we certainly have a variety of 'bigger' instruments, which are described in more detail: |
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IMS 3f SIMS
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Our IMS 3f SIMS (Secondary Ion Mass Spectrometry) is one of the earliest instruments from CAMECA's successful f-series of ion microprobes. We have modified various components of the instrument and added our own counting system in order to improve the stability and the signal-to-noise ratio. The 3f has been our workhorse for the measurement of isotopic compositions and trace element abundances for an extended period of time. The original instrument control has recently been converted to a new, LabView-based one. Related information: |
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NanoSIMS
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The first CAMECA NanoSIMShas finally arrived at Washington University and is now in full operation. This new type of ion microprobe offers a lateral resolution of better than 50 nanometers, a high sensitivity and multi-collection capability. To find out more about this exiting new analytical instrument, visit our NanoSIMS home page. Related information: |
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Auger Nanoprobe
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Installation of the new Auger Nanoprobe is complete and we are beginning to use this instrument for the first research projects. As a field emission scanning electron microscope (FE-SEM), the instrument was up and running immediately after installation. Qualitative elemental distribution images (for all elements except H and He) can also easily be acquired and this capability alone is very helpful for the characterization of many of our extraterrestrial samples which are heterogeneous on a sub-micrometer scale. Quantitative analyses in point mode are also possible, as we have shown in several proof-of-concept measurements. The required database of Auger elemental sensitivity factors for all elements of interest in a silicate matrix is currently being developed. Related information: |
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Transmission Electron Microscope (TEM)
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Our JEOL 2000FX TEM utilizes a fine beam of energetic (several hundred keV) electrons to provide high spatial resolution imaging and analysis of thin specimens. What makes the TEM a powerful instrument is its many different analytical capabilities. High magnification and atomic scale imaging and electron diffraction analysis are common features. In addition, the TEM gains analytical firepower from other instruments that can be joined to it. We have an energy dispersive X-ray system (EDS) that allows nanoscale elemental compositions to be determined, as well as a parallel electron energy loss spectrometer (PEELS) that permits analysis of the electronic structure of solids. |
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Scanning Electron Microscope (SEM)
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We use a JEOL 840A scanning electron Microscope. This SEM is also equipped with a NORAN VANTAGE DI+Digital X-ray Microanalysis and Advanced Imaging System which provides for automation of the SEM in order to carry out extensive imaging and X-ray mapping via program control. The X-ray system detects elements from Boron and above, and can provide quantitative EDS X-ray spectral analysis plus advanced particle sizing and chemical typing. Most of the materials investigated in the Laboratory for Space Sciences pass through the SEM lab first. Samples analyzed using the SEM include interplanetary dust particles, meteoritic polished thin sections, presolar grains, meteoritic acid residues, Greenland /Antarctic samples and terrestrial materials. |
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Ultramicrotome
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For viewing in the transmission electron microscope (TEM), specimens have to be thin enough to transmit high energy electrons (for 200 keV electrons, specimen thicknesses less than 100 nm are typically used). The diamond ultramicrotome (click on figure at left) is one means of getting multiple slices of the same specimen having the desired thickness. Typically a single presolar grain only a few microns in size (that may already have been studied in the SEM and ion microprobe) is placed with a micromanipulator at the bottom of a gelatin capsule. With the aid of a high magnification binocular microscope, carbon fiber are arranged around the particle to help locate it later. This material is covered with a low-viscosity resin that becomes very hard upon curing. Once the gelatin covering is removed, a 250 micron square plateau containing the grain and carbon fibers is then carved in relief from the resin using a sharp glass knife (see diagram). The resin block is then mounted into the ultramicrotome chuck that can be moved in increments as small as a few tens of nm. The plateau is then sectioned with a highly sharpened diamond, and the thin slices float off onto a water surface where they can later be retrieved for study in the TEM (usually on 3mm Cu grids covered with a 10 nm film of amorphous carbon). |
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Noble Gas Laboratory
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