Need elemental spatial distribution or quantitative elemental analyses of a solid material on a micro to nano scale? The WSU electron probe micro-analyzer may help!
The electron probe micro-analyzer provides elemental information, either qualitative or quantitative, about a solid substance, such as a rock, crystal, glass, alloy or thin film. The analytical resolution is about a micron and quantitative uncertainty is typically 1-2% relative. Scanning resolution is on the order of tens of nanometers.
Information derived is typically a quantitative elemental analysis, an image displaying contrast between phases (electron backscatter), or elemental (X-ray) maps.
Our JEOL 8500F field emission electron probe micro-analyzer was installed in 2008. The field emission (FE) electron gun provides a very small probe, on the order of one-half to one-tenth that produced by a conventional tungsten filament, even at high beam currents. Additionally, the FE gun is capable of very high beam currents, even at low accelerating voltage. Advantages include better light element analyses and faster mapping of low abundance elements. In addition, a cold finger reduces contamination during light element analysis.
The electron probe micro-analyzer is equipped with five wavelength dispersive X-ray spectrometers, and a Thermo Noran silicon drift energy dispersive X-ray spectrometer. The probe also routinely acquires cathodoluminescence and secondary and back scatter electron images.
Our electron probe micro-analyzer is used extensively for tephra identification and tephro-chronology. Off-campus groups, such as consulting companies, government agencies, and other academic institutions, may also use this service, which is supported by an extensive searchable database of western U.S. tephras.
more info will be added shortly
Our Agilent 7700 ICP-MS is a quadrupole mass spectrometer. All tuning parameters are software controlled and the software has the ability to monitor quality control parameters and re-calibrate, if needed, during a long sequence.
A Cetac ASX-510 auto-sampler is housed in a HEPA filtered enclosure and can handle 7, 15 and 50 mL sample tubes. Integrated peristaltic pumps handle variable speed uptake and automated dilutions at 5, 10, and 20 X. Our standard configuration is an all Teflon PFA nebulizer with a quartz, Scott-type, spray chamber. The 7700 maintains the temperature of the spray chamber at 2 degrees C. The plasma can be operated from 900 to 1400 W forward power, and is typically operated at 1250W. The octopole reaction cell can be used in helium mode to reduce interferences from polyatomics and narrow the kinetic energy distribution of the ions. Typical Argon gas flow conditions are 15 L/min plasma gas, 1 L/min auxiliary gas, 0.8 L/min nebulization gas, and 0.3 L/min make-up gas.
We use Nickel sampling and skimmer cones. Once inside the vacuum region, the positive ion beam is extracted from the expanding jet, focussed, offset by 1 cm to remove photons and residual neutrals, and then re-focussed into a unit mass resolution quadrupole mass filter. Detection by the electron multiplier is by pulse counting at low beam intensities and by current integration at high beam intensities (> 3.0 MHz).
Many metals can be analyzed in the low part-per-billion (ng/mL) region and slightly below and most metals can be analyzed to tens of parts-per-million (ug/mL). Consult with GeoAnalytical Lab staff about your particular metals and sample matrices before designing an experiment.
Our laboratory houses a ThermoARL Advant’XP+ sequential X-ray fluorescence spectrometer purchased in 2003. Samples are received from researchers and students at other universities from both the USA and other nations as well as from WSU School of Earth & Environmental Science students and faculty. Sample preparation and analysis usually takes about 2 months.
Samples received as rock or powder are prepared for analysis by chipping, grinding to a very fine powder, weighing with di-lithium tetraborate flux (2:1 flux:rock), fusing at 1000°C in a muffle oven, and cooling; the bead is then reground, refused and polished on diamond laps to provide a smooth flat analysis surface. Advantages of the low-dilution fusion method include full correction of matrix effects for all major and trace elements, robustness (we’ve stored beads for decades and rerun them with good results), economy of sample preparation time, and cleanliness of the instrument.
The same suite of elements is analyzed on our spectrometer for all samples (averages 65 minutes per sample), which includes the 10 major and minor elements of most rocks, plus 19 trace elements.