EXPERIMENTAL CONDITIONS

Electron Microprobe Analysis

 

RUN FILE : ______________________________________ DATE : ________________________

 

Laboratory Manager :

John J. Donovan
Department of Geological Sciences
210 Cascade Hall
University of Oregon
Eugene, OR, 97403

(541) 346-4632 (voice)
(541) 346-4692 (FAX)

Instrumentation :

Analyses were performed on a five spectrometer Cameca SX-51 wavelength dispersive electron beam microprobe, of 40.0 degree take-off angle. The WDS spectrometers include two high pressure and three low pressure P-10 flow proportional detectors and assorted analyzing crystals (LiF, PET, ADP, TAP, W/Si and NiCrBN). The instrument also includes :

- 138 eV resolution, 30K cps, Si(Li) EDS (energy dispersive) detector
- reflected and transmitted light optics (400X) with crossed polarizer (0.7 u depth)
- SE (secondary electron) detector (63 to 10000X magnifications) (topography)
- BSE (backscattered electron) detector (topography and atomic number contrast)
- CL (catho-luminescence) detector (trace element and crystal defect imaging)
- oxygen micro-leak and LN2 dewer for carbon contamination reduction
- 0.5 u stage resolution and reproducibility (X, Y and Z)

On-line data acquisition and reduction was performed by Probe for Windows software written by John Donovan, running on a DELL Pentium PC running at 133 Mhz with a 1 GB Mb hard disk drive for data storage and retrieval and 32 MB of RAM. Output was to an HP Laserjet 4M+ printer and/or an HP 1600CM color printer.

Comments :

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Analyzed Elements :

 

 

 

Operating Conditions :

____ KeV kilovolts (corrected for bias voltage drop)
____ nA nano-amps (sample current as measured on MgO)
____ sec seconds (typical count time for unknowns)
____ angstroms (carbon coat thickness using Spec-Pure evaporated carbon)
____ m microns (typical beam spot size)
____ m microns (maximum analytical volume diameter for light elements)

X-ray intensities were corrected for :

Beam drift (concurrent integration using beam current aperture)
Count time (normalized to ____ seconds)
Detector/amplifier dead-time losses
Standard count drift (linear interpolation in real time)
Spectral interferences (quantitative, iterated)

Off-peak backgrounds ( linear interp., aver., high, low, expon.)
MAN backgrounds (Mean Atomic Number, iterated, non-linear fit)
PHA (Pulse Height Analysis)

Matrix Corrections :

Oxygen calculated by stoichiometry to cations
Oxygen measured

Phi-Rho-Z
ZAF
Bence-Albee (constant)
Bence-Albee (linear)
Bence-Albee (polynomial)
Calibration curve (multi standard)

Absorption :

PHILIBERT (FRAME)
HEINRICH/AN. CHEM.
HEINRICH/1985 MAS [Heinrich, Microbeam Analysis--1985, 79]
LOVE/SCOTT -- 1983 [e.g., Love & Scott, J. Phys. D. 11, 1369 (1978)]
LOVE/SCOTT I -- 1985 [Sewell, Love & Scott, J.Phys.D. 18, 1233 (1985)]
LOVE/SCOTT II -- 1985 [Sewell, Love & Scott, J.Phys.D. 18, 1233 (1985)]
PACKWOOD/BROWN XRS [Brown-Packwood, X-ray Spec. 11, 187 (1982)]
BASTIN 1984/XRS [e.g., Bastin et al., X-ray Spec. 13, 91 (1984)]
ARMSTRONG MAS [Armstrong, Microbeam Analysis--1984, 208;--1982, 175]

Atomic number :

DUNCUMB/REED(FRAME)
LOVE/SCOTT
BROWN/BASTIN/JTA PHI(PZ)

Backscatter :

HEINRICH
LOVE/SCOTT

Mean ionization potential :

BERGER/SELTZER
DUNCUMB/DA CASA

Phi-Rho-Z equation :

REUTER
LOVE/SCOTT
NONE

Fluorescence Correction :

REED/ARMSTRONG (modified for M line and relative ionization)
REED/ARMSTRONG (un-modified)
REED/ARMSTRONG (modified for M line only)

Mass Absorption Coefficients :

LINEMU.DAT (Henke, 1985)
CITZMU.DAT (Heinrich, 1981)
Empirical (Selected MACs from Pouchou)

Spectral Interferences :

Interference Corrections Applied to Elements _____________________________

Area Peak Factors :

Area-peak factors from Bastin/Donovan

Volatile Element Correction :

Volatile Element Correction Applied to Elements _______________

 

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