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Electron Microprobe

Description:

The JEOL JXA-8600 is a conventional hairpin filament thermal emission electron microprobe that is more than 20 years old. It is capable of performing qualitative and quantitative X-ray microanalysis and secondary, backscattered, and topographic electron imaging on a wide variety of samples. It operates at currents ranging from 0.1 nA to greater than 2 mA) at accelerating potentials from 0.5 to 50 kV. The 8600 has a conventional energy dispersive X-ray (EDS) detector with resolution of 137 eV (Mn Kα). The probe also has 5 wavelength dispersive spectrometers (WDS) for high resolution (~ 10 eV) qualitative and quantitative analysis of elements from beryllium to uranium (Z = 5 – 92).  Three of the spectrometers have two crystals and two have four crystals. The 6500 is primarily used for surface compositional analysis to a maximum depth of about 4 mm in materials such as metals, alloys, composites, thin films, ceramics, semiconductors, glasses, and minerals. With Probe for Windows software, the instrument can be set up for automated analysis, making it possible to analyze dozens of samples overnight or over the weekend without operator intervention. With the WDS detectors it can be invaluable in the determination of microheterogeneity of materials, especially for those being evaluated as reference standards for microanalysis. EPMA is a highly precise, efficient method for determining the composition of a surface. Samples are often mounted in 2.54 cm (1 in) circular epoxy mounts although larger specimens can be accommodated. Bulk samples must be polished and flat for high quality quantification, and may have a 7 nm layer of carbon deposited onto the surface to improve specimen conductivity since insulating samples cannot be analyzed without a conductive coating. Many samples, particularly those with low atomic numbers may deteriorate under the electron beam, so careful dosing strategies must be employed for biological and insulating materials.

Specifications / Capabilities:

  • Qualitative and quantitative surface composition of elements from boron to uranium
  • Limits of detection between 10 and 100 ppm for most elements
  • Ultra fast EDS detector for producing X-ray images and x-ray maps of heterogeneous materials
  • Imaging and X-ray analysis possible with accelerating potentials between 1 kV and 30 kV
  • High resolution SE and BSE detectors for nano-scale imaging

Scientific Opportunities / Applications:

  • Compositional analysis of glasses, ceramics, thick and thin films, minerals, alloys, etc.
  • High resolution imaging and compositional analysis of particles
  • Analysis of cement and concrete samples
  • Particle searching and identification for dust, ash and contaminated surfaces
  • General surface chemistry and compositional analysis.
  • Microheterogeneity testing

Access Information:

 Individual collaborative projects to address NIST measurement needs are possible when the work is consistent with the Surface and Microanalysis Science Division mission space. Contact Jeff Davis to discuss possible collaborations.

Associated Programs/Projects:

  • Doubling the service life of concrete
  • Development of SRM 2063c Thin Film Standard
  • Low voltage X-ray analysis of fly ash particles
  • Participation in national and international quality assurance programs
probe
Credit: NIST
Contact

Name: Jeff Davis
Phone: 301-975-6988
Email: jeff.davis@nist.gov
Address:
100 Bureau Dr., MS 8371
Gaithersburg, MD  20899-8371


Name: Doug Meier
Phone: 301-975-4619
Email: douglas.meier@nist.gov