Electron energy analyzer, cylindrical

Our earliest alkali halide studies were performed with cesium halides, since the prevailing evidence (Table I) indicated that the vapor would be predominantly monomeric, and hence simplest to interpret. The apparatus employed for these studies (Figure 1) consisted of a cylindrical mirror electron energy analyzer, a non-inductively wound oven for generating the cesium halide vapor, and a helium resonance lamp. The spectra we obtained ( ) for the cesium halides are displayed in Figure 2. They reveal a clearly resolved doublet for Csl, a partially resolved doublet for CsBr, and broad single peaks for CsCl and CsF. We shall briefly reproduce here the arguments we used to interpret these spectra. 

Figure 1. Cylindrical mirror electron energy analyzer (2> ).

For time-resolved 2PPE spectroscopy, a combined set-up of an ultrafast laser system and an ultrahigh-vacuum photoemission spectroscopic system is indispensable. Typical electron energy analyzers have been used as the spectrometer, such as a cylindrical mirror analyzer, a hemispherical analyzer and a time-of-flight (TOF) analyzer. The TOF analyzer is mainly used for low repetition rate (<1 kFlz) laser sources, and the others are used for the lasers with multi-kldz or MHz repetition rates [11-14]. 

Figure 14.6 Cross-section of an electrostatic cylindrical electron energy analyzer. The electron source is the excited sample surface that is emitting photoelectrons.

The electron energy analyzer found to be most suitable for AES, the cylindrical mirror analyzer (CMA), has already been described in Section... 

HREELS experiments [66] were performed in a UHV chamber. The chamber was pre-evacuated by polyphenylether-oil diffusion pump the base pressure reached 2 x 10 Torr. The HREELS spectrometer consisted of a double-pass electrostatic cylindrical-deflector-type monochromator and the same type of analyzer. The energy resolution of the spectrometer is 4-6 meV (32-48 cm ). A sample was transferred from the ICP growth chamber to the HREELS chamber in the atmosphere. It was clipped by a small tantalum plate, which was suspended by tantalum wires. The sample was radia-tively heated in vacuum by a tungsten filament placed at the rear. The sample temperature was measured by an infrared (A = 2.0 yum) optical pyrometer. All HREELS measurements were taken at room temperature. The electron incident and detection angles were each 72° to the surface normal. The primary electron energy was 15 eV. 

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. 

Figure 3 demonstrates the electron spectrometer part of a depth-resolved conversion electron MOssbauer spectrometer specially designed for such measurements in our laboratory (10, 11). The electron spectrometer is of the cylindrical mirror type back-scattered K conversion electrons from resonantly excited Fe nuclei are resolved by the electrostatic field between the inner and outer cylinders (cylindrical mirror analyzer) and then detected by a ceramic semiconductor detector (ceratron). The electron energy spectra taken with this spectrometer indicate that peaks of 7.3-keV K conversion electrons, 6.3-keV KLM Auger electrons, 5.6-keV KLL Auger electrons, etc., can be resolved well, with energy resolution better than 4%. 

CMA cylindrical mirror analyzer DTA differential thermoanalysis EELS electron energy loss spectroscopy EDTA ethylenediaminetetraacetic acid... 

In electron spectroscopic techniques—among which XPS is the most important—analysis of the energies of electrons ejected from a surface is central. Because of the low kinetic energies involved in the techniques, analyzers using magnetic fields are undesirable. Therefore the energy analyzers used are exclusively of the electrostatic deflection type. The two that are now universally employed are the concentric hemispherical analyzer (CHA) and the cylindrical mirror analyzer (CMA). Since both have been used in XPS, both are described here, although in practice the CHA is more suitable for XPS, and the CMA for AES. 

AES measurements were carried out in a differentiated mode with a 2 eV modulation amplitude, at either 3 or 0.5 keV of primary electron energy, and 0.5 pA sample current, using a Perkin Elmer (PHI) 10-155 cylindrical mirror analyzer (CMA). The analysis was conducted at a low beam current to minimize electron beam damage. Spectra were acquired using a digital data acquisition system, and smoothed one time using a 11 point averaging technique.. 

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