The hemispherical deflector analyser revisited. I. Motion in the ideal 1/r potential, generalized entry conditions, Kepler orbits and spectrometer basic equation
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peer reviewed
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Journal of Electron Spectroscopy and Related Phenomena
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We re-examine the orbits of non-relativistic charged particles in a hemispherical deflector analyser (HDA) assuming an ideal 1/r potential. The particles start their trajectory within the HDA at the arbitrary entry radius r(0), within a circular entry aperture centered at R(0) at an arbitrary potential V(0) = V(R(0)). We present a vector treatment of the trajectories deriving many useful relations expressed as a function of the launching angle alpha. Refraction at the potential boundary at the entry of the HDA (modelled by an idealized step potential) is also considered and found to be important when V(0) not equal V(p), where V(p) is the plate voltage used for preretardation. We derive the analyser's generalized basic equation for deflection through 180degrees for which the principal reference ray is an ellipse rather than a circle as in the conventional HDA treatment. Both the conventional HDA, for which R(0) = (R) over bar and V(0) = V(p), as well as the paracentric HDA for which R(0) not equal (R) over bar and V(0) not equal V(p), where (R) over bar is the mean radius, are thus described as special cases of the same trajectory equation. Our results are expected to be of interest to all fields of electron spectroscopy, but particularly to those utilizing modem spherical sector analysers with sizeable interradial separation for accommodating large area position-sensitive detectors. This investigation is part of a concerted effort to investigate the refocusing properties of the paracentric HDA recently reported by Benis and Zouros [Nucl. Instr. & Meth. A 440 (2000) 462]. (C) 2002 Elsevier Science B.V. All rights reserved.
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motion in 1/r potential, kepler orbits, hemispherical analyser, electron spectroscopy, esca, fringing fields, spherical electrostatic spectrometer, energy-loss spectrometer, fringing field correction, multichannel detection, charged-particles, 2-d psd, resolution, optimization, design, trajectories
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<Go to ISI>://000178849500007
http://ac.els-cdn.com/S0368204802001378/1-s2.0-S0368204802001378-main.pdf?_tid=822b2526-4de8-11e3-b4a5-00000aacb361&acdnat=1384514856_5a60c43ea7c58946c931f97ac3998fed
http://ac.els-cdn.com/S0368204802001378/1-s2.0-S0368204802001378-main.pdf?_tid=822b2526-4de8-11e3-b4a5-00000aacb361&acdnat=1384514856_5a60c43ea7c58946c931f97ac3998fed
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en
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Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών