Electron Microprobes (EPMA)
Information on the Cameca SXFive Microprobe
The Electron Microprobe is a very powerful tool that uses certified standards and X-ray analysis to accurately identify and quantify major and minor element concentrations in a polished sample at the spatial resolution of an electron beam instrument.
The Wavelength Dispersive Spectrometers (WDS) equipped on the microprobes allow for superior X-ray energy resolution over typical EDS detection used in a Scanning Electron Microscope (SEM).The extended stage movement allows for x-ray mapping in which the spatial distribution of elements can be recorded over a large area revealing information about chemical zonation. Microanalysis using the Electron Microprobe can be applied to a wide range of materials including: geological samples, biomaterials (bone and teeth) and engineered materials (metals and ceramics).
The microprobe, sometimes referred to as EMP (electron microprobe) or simply "probe" - are equipped as follows:
- Installation from August 2012
- Tungsten source
- Five wavelength dispersive spectrometers with 140mm Rowland circle and the following analysing crystals and detectors:
- LTAP/LPET, P10 detector
- PET/TAP/PC0/PC2, P10 detector
- LPET/LLIF, HP P10 detector
- TAP/LPET, P10 detector
- LPET/LLIF, HP P10 detector
- Computer control by Cameca Peak Sight 6.1 and Probe Software Inc. "Probe for EPMA" and "Probe Image" software packages
- Integrated Röntec X-Flash 5010 Be-window SDD EDS with Bruker Quantax 2.1.1 Esprit software (elements Na-U)
- Cameca SE, BSE and CL detectors
- Built-in reflected light optical microscope
- Oil-free vacuum system with ion, turbomolecular and scroll pumps
The CAMECA Microprobe is a very powerful microanalytical tool and has a number of significant advantages over a microanalysis via conventional SEM:
- Superior energy resolution using Wavelength dispersive X-ray analysis i.e. 10eV (cf 140eV with conventional EDXS), enabling the researcher to resolve problematic overlaps during analysis of X-ray spectra.
- Capacity to provide quantitative elemental analysis via calibration of x-ray data against reference standard materials.
- The SXFive is equipped with large diffracting crystals and software ability to sum spectrometers can give low 10’s ppm detection limit for some elements.
- Ability to map over large areas, i.e. up to 75mm x 50mm via stage mapping, and on the SXFive give fully quantitative ZAF corrected x-ray maps.
- Improved capability for multi-element imaging. Whilst major elements are being imaged using the integrated EDS software trace elements requiring better detection limits or energy resolution are being mapped using WDS at the same time.
Recommended Sample Size:
Polished Blocks – Different resin mount holders allow 3x35mm or 6x25mm diameter samples at one time. Blocks must have a 20mm max height but ideally ~10mm.
Polished Slides – Slide holder allows up to 3x 47 x 25mm, 1x 75 x 50mm, OR 1x 75 x 25mm at a time.
Figure caption: Full ZAF corrected quantitative maps of gold nugget (Image permission provided courtesy of Dr Frank Reith and Angel Rea). View a larger version.