Electron Probe Microanalysis

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The Electron Probe MicroAnalyser (EPMA) is a non-destructive technique for the analysis of polished solid materials. In September 2021, we took delivery of a Jeol Field Emission Gun (FEG) JXA-iHP200F microprobe. The instrument is equipped with 5 wavelength dispersive spectrometers (WDS), and EDS detector, panchromatic CL detector and and IBSS plasma cleaner. In addition to a full Jeol-EMPA software suite, we have Probe for EPMA (PfE) available for chemical analysis and elemental mapping.

The instrument provides a service to the Earth Sciences Community as well as to all other departments within the University of Cambridge.  We also welcome work from outside the University, both academic and/or commercial. 

The FEG – EPMA provides crisp clear imaging capabilities is capable of quantitative analysis of individual points (1-30 microns in diameter) or over small (usually no more than 1mm2) areas of the sample surface to produce a quantitative (or qualitative) map.  The FEG enables an excellent beam stability at a large range of currents (1-1000 nA).  An accuracy of about ±1% for major elements, and detection limits ranging from 20 to 1000 ppm can be attained.

1. Academic Staff Member:Dr Oscar Branson

2. Contact: Please email the lab manager,  Dr Iris Buisman

First-time usersshould arrange to meet and discuss the measurement strategy appropriate to their research and techniques of sample preparation.

Peak demand for the EPMAtypically occurs from October to January. At other times of the year, the EPMA is usually over-subscribed and waiting times are typically 3-6 weeks. 

Booking the instrument Please email Iris Buisman to request a slot.

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From 1st December 2024, please do the following:

To look at availability and book, please look at: PPMS

NOTE:to book a slot for this instrument you will need to have read and signed:

  • All health and safety forms
  • agree to the terms and conditions of the lab and computer rules
  • book and complete training

Before being signed off as an independent user your session will have to be approved by Dr Iris Buisman.  As an independent user you will be able to book as you please.

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Additional information:

  • Sample preparation

Accurate analysis is possible only if the sample is well polished.  We have holders that can accommodate thin sections 46-48mm long x 10-30 mm width and stubs of 25 or 30mm diameter. Samples that are not electrically conducting (including most rocks and minerals) must be coated with a conducting layer, typically carbon.  Please make sure your samples are coated before your session on the instrument.

  • Precautions

Users are trained and supervised by Dr Iris Buisman. Operating instructions for the equipment are clearly set out. Provided these instructions are followed, no special hazards exist. The probe may only be operated out of normal working hours by users who have received permission and completed the "Out of Hours Permission Form" for this equipment.

Any instrumental fault should be reported to Iris Buisman.

  • References

New probe users are encouraged to read chapters relating to X-ray generation, equipment set up and EPMA in:  Electron Microprobe Analysis and Scanning Electron Microscopy in Geology by S.J.B. Reed, Cambridge Univ. Press, 2nd ed. 2005