Electron Microprobe Laboratory
Chemical analyses, elemental mapping, and scanning electron imaging of geological and man-made materials.
Contact: Dr. Marty Yates
Cameca SX-100
Column Configuration
- Self-biasing LaB6 cathode
- Two stage electromagnetic condenser lens
- Fully automated alignment, focus, astigmatism correction, electron gun, beam current, beam scanning, and beam diameter
- Double aperture beam regulation of beam current from .5 to 300 nA
- Retractable Faraday cup for direct beam current measurement
- Electron absorbing column liner tube
X-ray Spectrometers
- 5 vertical wavelength dispersive spectrometers
- 1 Röntec XFlash 2000 energy dispersive spectrometer
- 160 mm spectrometer Rowland circle
- 40 degree x-ray take-off angle
- .22 to .83 sin-theta spectrometer range
- Spectrometer resolution 1E-5 sin-theta
- Programable scanning pulse height analyzers
Spectrometer Configuration
| Crystal | 2d | Formula | K-Shell Range | L-Shell Range | M-Shell Range | |
| Spectrometer 1 | LTAP | 2.7745 nm | C8H5O4TI | F-P | Mn-Nb | Ag-Ir |
| 1 Atm P10 mylar window | LPET | 0.8742 nm | C5H12O | Si-Mn | Sr-Tb | Ta-U |
| Spectrometer 2 | TAP | 2.7745 nm | C8H5O4TI | F-P | Mn-Nb | Ag-Ir |
| 1 Atm P10 mylar window | LPET | 0.8742 nm | C5H12O | Si-Mn | Sr-Tb | Ta-U |
| Spectrometer 3 | LPET | 0.8742 nm | C8H5O4TI | Si-Mn | Sr-Tb | Ta-U |
| 3 Atm P10 mylar window | LLIF | 0.4027 nm | LiF | Sc-Rb | Te-U | Ag-Ir |
| Spectrometer 4 | LPET | 0.8742 nm | C5H12O | Si-Mn | Sr-Tb | Ta-U |
| 3 Atm P10 mylar window | LLIF | 0.4027 nm | LiF | Sc-Rb | Te-U | Ag-Ir |
| Spectrometer 5 | TAP | 2.7745 nm | C8H5O4TI | F-P | Mn-Nb | Ag-Ir |
| 1 Atm P10 polypropylene window | PC1 | 60 nm | W/Si Multilayer | C-F | — | — |
| PC2 | 95 nm | Ni/C Multilayer | B-O | — | — | |
| PC3 | 200 nm | Mo/B4C Multilayer | Be-B | — | — |
Energy Dispersive Spectrometer
- Röntec XFlash 2000 Detector
- LN2-free operation
- Analysis of element ranging in atomic number from Na to U
- Resolution <159eV at 1000 counts/sec and < 170eV at 30,000 counts/sec
- Röntec EDS Software
- Spectrum acquisition and processing
- Quantitative ZAF analysis
- Standardless quanitative analysis
- Bremsstrahlung modeling
- Integrated expert system
Sample Handling
- Sample change airlock
- Stage movement: X-axis 50mm; Y-Axis 80mm; Z-axis 1.5mm
- Stage positioning via linear optical encoders
- Stage reproducibility: 1 micrometer
- Stage minimum step size: 100 nanometers
- Stage speed 15 mm/sec
- Two sample holders
Vacuum System
- Magnetic bearing turbomolecular pump
- Direct drive roughing and backing mechanical pumps
- Electron gun pumping by ion pump
Anticontamination System
- Oxygen gas jet
- LN2 cold plate
- Magnetic bearing turbomolecular pump
- .2%/min. contamination rate without anticontamination
- .025%/min. with LN2 cold plate only
- Near zero contamination with combined gas jet and LN2 cold plate
Imaging Capability
- Secondary Electron Imaging
- 40X to 400,000X magnification
- Images up to 2048 x 1536 pixels
- Automated and manual photomultiplier voltage and collector bias
- Raster rates from 20 msec to 245 sec per frame
- Backscattered Electron Imaging
- Topographical, compositional, and orientation image modes
- 6 BSE detector sectors coinciding with x-ray spectrometer ports
- 15 nm spatial resolution
- Cathodoluminescence
- X-ray compositional images
- Images up to 2048 x 1536 pixels
- Acquisition of up to 13 x-ray channels; 8 EDS and 5 WDS
- Light optical images
- Continuous zoomed view from .25mm to 1.75mm
- Transmitted light with polarizer and analyzer
- High resolution color CCD camera
- Optical resolution .7 micrometers
- Real-time optical image frame grabber
- Dedicated CRT monitor
Analytical Capability
- Analysis of elements ranging in atomic number from Be to U
- Analysis of elements ranging in concentration from 100% to 10 ppm
- Automated full matrix corrections using the PAP, Pouchou & Pichoir (1987) or X-Phi, Merlet(1995) models
- Analysis of up to 13 elements simultaneously
- Analysis of up to 40 elements per analytical point
Automation Hardware
- Computer Workstation
- Dual 18″ LCD monitors
- Video frame acquisition board
- Color Laserwriter printer
Software
- Windows-based Peak Sight software
- Cameca Expert Assistant
- Monazite Geochronology Analysis
- Geological Sample Quantification
- Sample Navigation
- Multiple Phase ID
- High Performance Phase Mapping
- Dynamic Beam Tracking
- Profile Reconstruction