Dual anodes

Fig. 19. Schematic of dual anode (typically Al and Mg) x-ray source. X-rays produced by electron bombardment of anode face 2 indicated (19). The routine dual-anode x-ray source just described generates nonmonochromatized x-rays in a relatively large spot size (ca 1 cm in diameter). In...

XPS spectra were obtained using a Perkin-Elmer Physical Electronics (PHI) 555 electron spectrometer equipped with a double pass cylindrical mirror analyzer (CMA) and 04-500 dual anode x-ray source. The x-ray source used a combination magnesium-silicon anode, with collimation by a shotgun-type collimator (1.). AES/SAM spectra and photomicrographs were obtained with a Perkin-Elmer PHI 610 Scanning Auger Microprobe, which uses a single pass CMA with coaxial lanthanum hexaboride (LaBe) electron gun. 

The PHI Model 548 ESCA/ AES spectrometer (Physical Electronics Inc., Eden Prairie, MN) previously described (10,13) has been modified by the replacement of the original x-ray source with a PHI Model 1548 dual anode, 300W x-ray source. All binding energies are referenced to the Au 4f peak at 83.8 eV. 

Fig. 19. Schematic of dual anode (typically Al and Mg) x-ray source. X-rays produced by electron bombardment of anode face 2 indicated (19).

All XPS or ESCA measurements were performed using a Perkin Elmer 5300 ESCA spectrometer equipped with a dual anode (Mg, Al) X-ray source, differentially pumped Ar+ sputter gun, and the variable angle measurement set-up for angle-resolved photoelectron spectroscopic measurements. The data collection and treatment, e.g. smoothing, curve-fitting, intensity measurements, were accomplished by a Perkin Elmer 7500 dedicated computer system using PHI software package. 

XPS was used in Che Li project co characterize Che adsorption of THF on Li surfaces. It was performed in a Perkin-Elmer UHV chamber. The photon source was a Al-Mg dual anode X-Ray gun. The Mg anode was used in this work. The energy of the major Mg x-ray line is 1253.6 eV with a FWHM of 0.65 eV. Mg also has x-ray satellites at energies 8.4, 10.2 17.5, 20 and 48.5 eV higher than the major line. These satellites will cause corresponding satellite peaks of a major XPS peak. The gun was operated at 15-KeV and a power of 400 watts. The incident angle of the photons was typically 55 and the take-off angle of the photoelectrons was 0° with respect to the normal of a sample surface. 

Surface analysis (AES/XPS) Electron spectroscopy for elemental analysis of surfaces, sensitive to as low as two atomic layers. Physical electronics model PHI-570 Auger Electron Spectroscopy/X-ray Photoelectron Spectroscopy System is a double pass cylindrical mirror energy analyzer with dual anode (Mg/Al) X-ray source and has a rapid sample introduction probe. It can detect elements at the first five to ten atomic layers of sample and detect all elements except H and He. 

Radiation Source. The radiation source used in ESCA is a standard X-ray anode tube, as described in Chapter 8. Soft X-rays are used, with A1 and Mg being the most common anodes. Many commercial systems offer a dual anode X-ray tube so that the analyst can switch between excitation wavelengths. It is very important that the X-ray source be monochromatic, with a linewidth extending over as narrow an energy range as possible. A1 and Mg have narrow K emission lines. The Mg K line has an energy of... 

A wide variety of x-ray tube anode materials are available. The more commonly used anodes are chromium, rhodium, tungsten, and molybdenum. In addition, aluminum, copper, silver, gold, and platinum have all been employed as single anodes. Dual-anode tubes, combining two different anode materials, are also used to provide more flexibility in the choice of excitation condition. Tungsten with chromium and molybdenum with tungsten are two of the more common combinations. Other pairs have also been used to optimize excitation for a particular application (e.g., rhodium combined with tungsten). 

Hawn (1983) has described the performance of a dual-anode X-ray source for XPS using various un-collimated and collimated configurations to make it effective in increasing the signal-to-background ratio and reducing anode cross talk without substantial signal loss. 

J.D. Burk, Dual Anode Field Performance Evaluation-Cathodic Protection for Ojf shore Structures Corrosion/91, Paper No. 309, NACE, Houston,... 

X ray photoelectron spectroscopy (XPS) was performed on a Riber MacII XPS instrument (non-monochromated dual anode Al/Mg Ka X ray source, 5 10 ° Torr in analysis chamber, 12 kV / 10 mA power, 50 / 43 ° X-ray incidence / photoelectron take-off angles, 0.9 eV resolution, 0.05 eV / 100 ms steps). C(ls) photoionization peak at 285.0 eV was used for energy calibration. Surface sputtering was achieved with a Riber Cl 50 ion gun (3.0 keV Kr, 4.0 lO " nm.s ). The effects of the thermal treatments were monitored by deriving the ions surface concentrations from the... 

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