Instrumentation

 
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Our NanoSIMS 50, the first one produced by CAMECA, was designed specifically for the presolar grain research that we do. This new type of ion microprobe offers a lateral resolution of better than 100 nanometers, high sensitivity and multi-collection capability. To find out more about this instrument, visit our NanoSIMS home page.

Our PHI 700 Auger Nanoprobe operates with a field emission electron source and can be operated as a field emission scanning electron microscope (FE-SEM). In addition, qualitative  and quantitative analyses (for all elements except H and He) can be carried out with a spatial resolution on the order of 10s of nanometers, making it an ideal complement to the NanoSIMS. For more information about the Auger Nanoprobe, visit our Auger Nanoprobe home page.

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, atomic scale imaging, and electron diffraction analysis are common features. In addition, we have an energy dispersive X-ray system (EDS) that allows the determination of nanoscale elemental compositions, as well as a parallel electron energy loss spectrometer (PEELS) that permits analysis of the electronic structure of solids.

We use a JEOL 840A scanning electron microscope. This SEM is equipped with a LaB6 emitter and ThermoNoran Si(Li) light element detector, which allows detection of elements from boron and above. The SPRITE stage controller allows continuous movement in the x, y and z directions.  The SEM runs with Noran’s System 7 spectral imaging software and, for certain types of analyses, can run in automated mode, allowing unattended data acquisition.  

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 (at right) is one means of getting multiple slices of the same specimen with the desired thickness. Typically a single presolar grain only a few microns in size is placed with a micromanipulator at the bottom of a gelatin capsule.

The noble gas laboratory consists of two Super Gnomes, made in our own shop, which define state-of-the-art noble gas mass spectrometry. These combine ion-counting detection with an ion optic design to maximize sensitivity, and are capable of measuring a few thousand atoms. Coupled to these instruments are two lasers for sample extraction, a 100 watt Nd-YAG and a short pulse UV laser, which are used for noble gas measurements of individual grains of less than a microgram. A computer-controlled x-y stage allows in situ noble gas measurements and the recovery of noble gases from collector material exposed to the sun during the Genesis solar wind mission.

The equipment in our laboratory includes sample preparation equipment, such as optical microscopes, clean benches, polishing and sawing equipment, balances, ovens, an ultrasonic cleaner, evaporators, microbalances, a clean room with micromanipulators and a meteorite processing lab. In addition, we have a variety of 'bigger' instruments, described below. If you have a sample you would like to have analyzed, please fill out our Request Form.

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Transmission Electron Microscope (TEM)
Scanning Electron Microscope (SEM)
Ultramicrotome
Noble Gas Laboratory

With the aid of a high magnification binocular microscope, carbon fibers 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 carved in relief from the resin using a sharp glass knife. 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 3 mm Cu grids covered with a 10 nm film of amorphous carbon).

(Left to right: Christine Floss, Maitrayee Bose and Frank Stadermann)

(Thomas J. Bernatowicz)

(Alex Meshik)

(Thomas J. Bernatowicz)

Our focused ion beam (FIB) instrument extends the reach of our studies into the submicron realm.  Our instrument is a FEI 3D FEG Dual Beam (electron beam and gallium ion beam) FIB with an in situ Omniprobe manipulator.  The FIB allows us to image and manipulate submicron presolar grains as well as to cut and extract sections sufficiently thin for transmission electron microscopy (TEM).   

Focused Ion Beam Instrument (FIB)