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The 50-096 will retain the 15 keV setting until it is manually turned off or there is a power interruption.

SELECTING

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The pass energy determines the energy that detected photoelectrons will have as they pass through the hemispherical analyzer. The lower this energy is, the better the energy-resolving capability of the analyzer is. However, as pass energy is lowered to improve energy resolution, the intensity of the detected photoelectron peaks is reduced. This relationship is nearly linear (when the pass energy is reduced by a factor of two, so is the detected count rate). When elemental information is of primary interest, such as in survey spectra, a high pass energy and a large data step size should be used. When detailed chemical information is being sought, a lower pass energy and smaller data step sizes should be used. By selecting a pass energy that is no lower that necessary to resolve the ESCA peaks of interest, you will maintain as high a count rate as possible and improve the efficiency of your experiments.

 

SELECTING THE SIZE OF ANALYSIS AREA

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Analysis area for a given combination of aperture and analyzer input lens magnifications.Analysis

                                                          Analysis Area Size
Aperture #Minimum Small Large
1 30 μm diameter #     Minimum                                Small                                     Large
1                    30 μm diameter                     -----                                        -----
2 120 μm diameter 180 μm diameter 02                    120 μm diameter                   180 μm diameter                    0.4 mm diameter
3 400 μm diameter 600 μm diameter 2 mm diameter
4 800 μm diameter 1100 μm diameter 4 mm diameter
5 03                    400 μm diameter                   600 μm diameter                    2 mm diameter
4                    800 μm diameter                   1100 μm diameter                  4 mm diameter
5                    0.6 x 2.0 mm 1                          1 x 3.5 mm                            3 x 10 mm

Physical Electronics recommends using the minimum mode for most analysis
and selecting as large an aperture as possible for the sample that you have, in
order to maximize sensitivity and minimize data collection time. For Auger
analysis, Physical Electronics recommends using either Aperture 4 or 5 along
with the small or minimum lens area magnification.

 

SELECTING A PASS ENERGY

 

The pass energy determines the energy that detected photoelectrons will have as they pass through the hemispherical analyzer. The lower this energy is, the better the energy-resolving capability of the analyzer is. However, as pass energy is lowered to improve energy resolution, the intensity of the detected photoelectron peaks is reduced. This relationship is nearly linear (when the pass energy is reduced by a factor of two, so is the detected count rate). When elemental information is of primary interest, such as in survey spectra, a high pass energy and a large data step size should be used. When detailed chemical information is being sought, a lower pass energy and smaller data step sizes should be used. By selecting a pass energy that is no lower that necessary to resolve the ESCA peaks of interest, you will maintain as high a count rate as possible and improve the efficiency of your experiments.


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CONTACT: Jorge A. López (jorgelopez@utep.edu

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