School of GeoSciences

Sample Requirements

This page provides details of the requirements for sample preparation prior to analysis at the Electron Probe Microanalysis Facility

  • Samples must be vacuum compatible and stable under electron bombardment.
    • The operating vacuum is approximately 10 -5 Pa

 

  • For quantitative analysis the specimens must be flat, well-polished and as free from surface voids as possible.
    • Final polishing should use 0.25 micron abrasive
    • Samples with porosity should be vacuum-impregnated with resin to fill void space

 

  • Samples must be cohesive, so as not to shed particles whilst in the SX100

 

  • Samples must be in a format compatible with the SX100 sample holders, which accomodate most standard formats. Permitted formats are:
    • Thin sections: 45-48mm long, up to 25mm wide, 1mm thick with up to 0.5mm thick polished sample above the glass slide
    • Disks: 25.5mm or 29.5mm diameter, thickness 5-25mm
    • It may be possible to accommodate other formats - please discuss details with Chris Hayward
    • Please use epoxy resin for sample preparation. Lakeside, Canada Balsam and styrene-based resins must not be used for preparation.

 

  • Insulating samples need to be coated prior to analysis with a thin film of carbon. This is done at Edinburgh.
    • Samples should arrive at the Facility two working days before the EPMA session for coating
    • Samples must be cleaned after polishing to remove abrasive particles and lubricants. This can be done at Edinburgh if necessary.
    • Other coating materials such as gold can be used if required, but please discuss this as far in advance of making a booking as possible.

 

Facilities exist at Edinburgh for users to prepare certain types of sample prior to EPMA analysis - please contact Chris Hayward to information.

Please discuss any queries related to sample preparation or format with Chris Hayward well in advance of your scheduled EPMA booking