YALE ELECTRON MICROPROBE & SEM LABORATORY

YALE ELECTRON MICROPROBE & SEM LABORATORY
Kline Geology Laboratory Room 327, P.O. Box 208109, New Haven, CT 06520-8109 203-432-3181

NSF Instrument Upgrade (IF/EAR-0744154) and Yale University Fund Installation of JEOL JXA-8530F
The JEOL JXA-8530F (FEG) “Hyperprobe” now is installed; testing toward appropriate behavior and consistency continues. This electron probe microanalyzer (EPMA; aka electron microprobe analyzer, EMPA) permits imaging of features as small as 5-10 nanometers and quantitative analytical (chemical) resolution of features perhaps as small as 200 nm (~800 nm @10 kV). This analytical resolution applies to both quantitative analysis and extremely high-resolution chemical mapping. UPDATE: At present, our capabilities for microprobe analysis are complete, though some sporadic stability problems remain with software, communications, and beam current. We are accomplishing numerous sessions as time is available, including WDS quantitative work, electron imaging, EDS qualitative inspections, qualitative WDS scans, and sample chemical mapping (including WDS). Schedule updates and current constraints can be found here. Thanks for your interest, and please stay tuned for details…

We invite your interest in our electron microprobe/SEM facility. For more information, please contact Jim Eckert using the information at the bottom of this page. With this system we are able to acquire data with the native JEOL interface. We also plan ultimately to regain the ability to acquire data with the Probe-for-Windows software we used previously with the JXA-8600; apparently this still shall be a while coming. For the most current schedule information, please click here for the Yale-Microprobe Calendar.
Thank you.

–> –>

General Features of the ELECTRON MICROPROBE

(If you are not familiar with electron-microprobe fundamentals, you may wish to follow this link.)

THE YALE MICROPROBE FACILITY
(GEOLOGY AND GEOPHYSICS)

The Yale University microprobe facility houses a JEOL JXA-8530F (FEG) “Hyperprobe” - electron probe microanalyzer (EPMA; aka electron microprobe analyzer, EMPA) - installation of which began in April 2009. This EPMA/SEM functions with state-of-the-art imaging, analytical, and computer-control capabilities. This probe configuration includes five wavelength-dispersive spectrometers (WDS) and a light-element-capable energy-dispersive spectrometer (EDS) with Windows-XP processing software. Hardware and software allow automated operation and data collection, and software accommodates advanced image processing and feature analysis. Additional instrumental details can be accessed here. This lab also includes a turbo-pumped Emitech carbon evaporator/coater, which also includes metal evaporation capability. Jim Eckert is available to answer questions and assist users with all forms of analysis. For information on access and scheduling, click here

USES OF THE MICROPROBE, 1. IMAGING:

Since the microprobe functions also as a scanning electron microscope (SEM), in addition to element maps of a specimen, images from secondary electrons (SEI) and back-scattered electrons (BSE, a.k.a. COMPO or BEI) also can be produced. The Yale JXA-8530F rivals or surpasses most SEMs in the ability to resolve detail and represent with clarity the textural relationships in a specimen. This capability, coupled with the quantitative analysis described below, permits detailed microscale to nanoscale assessment of a specimen. SEM imaging with the 8530F can routinely apply magnifications over 50,000X. For a brief discussion of imaging resolution, click here.

USES OF THE MICROPROBE, 2. MICROSCALE CHEMISTRY

QUALITATIVE ANALYSIS

Qualitative and semi-quantitative microscale chemistry can be assessed rapidly using EDS spectrometry. This can benefit phase identification and recognition of compositional variability in a sample. This allows rapid imaging and compositional mapping, as well as storage of images and data in readily transferable formats. With either the native JEOL acquisition software or with Probe for Windows, we also can accommodate integration of EDS data into the quantitative-analysis package.

QUANTITATIVE ANALYSIS

Quantitative microscale chemical analysis, using wavelength dispersive spectrometry (WDS), requires both a stable, well-tuned instrument and standards for comparison that are both well characterized and appropriate for a given specimen. The JXA-8530F is proving to be a very stable instrument, and the Yale suite of available standards is quite diverse and extensive. Typical operating conditions for the electron beam are an accelerating voltage of 15 kV beam currents of 5 to 20 nanoamps, and beam diameter of 5 to 10 microns. However, these parameters can be varied widely (0.5 - 30 kV, ~10 pA to ~1500 nA) to address various questions. Many of the Yale standards, a collection begun by Horace Winchell in the 1960’s, are appropriate representatives of their mineral group. These generally high quality standards, which include both synthetic and naturally occurring varieties, have been graciously provided by a wide variety of esteemed scientists over several decades. Nonetheless, alternative standards for less traditional projects also can be applied.

Quantitative analysis can address all elements heavier than beryllium (boron and higher). Each analysis takes several minutes to count the X-rays and perform related calculations. Ultimate WDS detection limits for sodium and heavier elements are about 50 to 100 ppm (0.005 to 0.01 wt%, elemental); for lighter elements, the instrument is somewhat less sensitive. For most major elements, these truly quantitative microscale chemical measurements typically have accuracy and precision on the order of 1%. Comprehensive setups applied heretofore include a 33-element oxide setup, incorporating all REE with overlaps and interferences. Automated analysis allows the operator to assign locations for analysis during a session, then acquire data automatically (unattended) at those stored locations. Thus, the operator may concentrate on other tasks while the time-consuming X-ray counting and data reduction are completed. Data can be transferred via network or USB connections for rapid accommodation into reports and manuscripts.

APPROPRIATE SPECIMENS

Appropriate specimens for microprobe imaging and analysis can be geological, biological, or technical materials of various compositions and textures. To be appropriate, specimens must be:

• solid and dry with a clean surface
• stable in a vacuum and under a high-voltage electron beam (some less stable materials can be evaluated under less intense voltage and current, though this limits quantitative potential)
• polished on the flat upper surface (for quantitative analysis) - this can be completed in the lab here, if needed
• mounted on either:
  1) 25.4 mm (1”) diameter cylindrical blocks, plates, or discs;
  2) 27 mm wide (standard petrographic {U.S.}) glass slides or thin (~1 mm) plates up to 80 mm long (45 mm standard);
  3) another substrate no more than 100 mm X 100 mm and 25 mm thick (high)
• able to conduct an electrical current or to be coated with a thin layer of conductive carbon (coating ideally performed in the lab here).

ACCESS

Current hourly usage rates are available here. We encourage use by both academic and corporate institutions; please contact Jim Eckert if you have an interest in this facility. Operating time may be arranged as available. However, at least 1.5 or 2-week advance scheduling always is recommended, especially if any training or operator assistance may be required.  
PLEASE BE ADVISED: Scheduling “crises”, requiring immediate analysis, generally cannot be accommodated on short notice; if possible, please plan ahead. Thank you.

For the Upcoming Schedule, Yale-Microprobe Calendar, click here

Training

Periodically, a training course for the JEOL 8530F shall be run; follow this link for current information. Alternatively, training on the machine can be arranged directly with Jim Eckert.

Other Microprobe Resources

A page listing a few other microprobe resources and useful links can be found by clicking here.

Contact:

Please send any comments or questions to Jim Eckert. 1.5 or 2-week advance scheduling always is recommended, especially if any training or operator assistance may be required. 
PLEASE BE ADVISED: Scheduling “crises”, requiring immediate analysis, generally cannot be accommodated on short notice; if possible, please plan ahead.–> Thank you.

JAMES O. ECKERT, JR., Ph.D.
Laboratory Manager, Electron Microprobe and XRD Facilities, KGL 327
Office: KGL 327 Voice: 203-432-3181
Alt.#1 (@probe) 436-9182 Alt.#2 (@XRD) 432-5169 FAX: 203-432-3134

email: Jim Eckert

var dateMod = “” ;dateMod = document.lastModified ;document.write(“Last Updated: “); document.write(dateMod); document.write(); // –>

Designated a “Links2Go Key Resource” Laboratory Site (July 2000)