Electron probe microanalyzer (EPMA)
The field-emission gun electron probe microanalyzer in the GeoLab, a JEOL JXA-8530F Hyperprobe, is a state-of-the-art instrument. It is part of the Dutch National Geological Facility (collaboration between Utrecht University, VU Amsterdam, and Naturalis Museum of Natural History) and its installation was completed in 2014.
What it can do:
- Acquire major, minor and trace (30 – 300 ppm, matrix-dependent) element concentrations in minerals, glasses and other solid materials
- Wavelength-dispersive (WDS) and energy-dispersive (EDS) analysis of elements from boron to uranium
- High-resolution imaging using secondary-electron, backscattered-electron, spectrally resolved cathodoluminescence, and WDS X-ray signals
- High spatial resolution achieved through a Schottky-type field-emission gun, resulting in a highly focused (30 – 50 nm) electron beam on the sample surface
- Quantitative analysis of features below 1 micron under low-kV conditions
What it cannot do:
- Highly volatile materials (the instrument operates under high vacuum: 1E-4 Pa)
- Organic materials (we can detect presence of carbon, but not quantitatively as these organics tend to volatilize under the beam). Carbon distribution mapping and qualitative analyses may be possible.
- Five WDS spectrometers with the following configuration:
- Spectro 1 TAP LDE1 (Gas flow)
- Spectro 2 PETL LIFL (Sealed xenon)
- Spectro 3 TAPH PETH (Gas flow)
- Spectro 4 TAPH LDE2 (Gas flow)
- Spectro 5 LIFH PETH (Sealed xenon)
- Integrated JEOL EDS with <129 eV SDD detector (liquid N2-free)
- Gatan panchromatic cathodoluminescence detector (greyscale with filters)
- xCLent hyperspectral cathodoluminescence system
- High-precision stage (reproducibility about 0.6 microns)
- Anti-contamination coldfinger (liquid N2-cooled)
- Sample holders for rectangular thin sections (25 x 48 mm) and 1-inch rounds. Other sample dimensions can be accommodated. Please contact us in advance.
The JEOL operating software is solid and easy to use, but we chose to do our quantitative WDS analyses using a third-party software developed by John Donovan (Probe for EPMA software). It offers unique and powerful options that we use frequently, such as non-linear background corrections for trace element analysis, multi-point background corrections for very complex matrices, and time-dependent intensity corrections for volatile elements or Na migration.
We acquire X-ray distribution maps with the JEOL software.
- Hyperspectral CL imaging:
Acquisition and data reduction of spectrally resolved cathodoluminescence images of CL-active materials (zircon, quartz, feldspars and other Fe-free materials), using the hardware and software developed by Colin MacRae (CSIRO, Australia).
Rates (excl. VAT):
- Consortium users: EUR 200/day for members of the UU, VU, and Naturalis
- Other academic users: EUR 400/day
- Commercial users: EUR 1200/day