Novel and traditional fringing field correction schemes for the hemispherical analyser: comparison of first-order focusing and energy resolution

Results from the simulation of a biased paracentric hemispherical deflector analyzer (HDA) with injection lens are presented. The finite differences electron optics software SIMION was used to perform Monte Carlo type trajectory simulations in an effort to investigate the focusing effects of the HDA entry and exit fringing fields which are used to improve energy resolution - a novel feature of this type of analyzer. Comparisons to recent experimental results are also presented. Biased paracentric HDAs represent a novel class of HDAs, which use the lensing action of the strong fringing fields at the HDA entry, to restore the first order focus characteristics of ideal HDAs in a controlled way. The improvement in energy resolution and transmission without the use of any additional fringing field correction electrodes is of particular interest to modern analyzers using position sensitive detectors.

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X-Ray Spectrometric Properties of Potassium Acid Phthalate Crystals

Advances in X-ray Analysis ◽

10.1154/s0376030800011459 ◽

1969 ◽

Vol 13 ◽

pp. 373-381 ◽

Cited By ~ 2

Author(s):

R. J. Liefeld ◽

S. Hanzgly ◽

T. B. Kirby ◽

D. Mott

Keyword(s):

Oxygen Atom ◽

Energy Range ◽

Energy Resolution ◽

Reflection Coefficients ◽

X Ray ◽

First Order ◽

Coefficient Of Reflection ◽

Potassium Acid Phthalate ◽

Order Parallel ◽

Acid Phthalate

The results of two crystal measurements of potassium acid phthalate crystal first order parallel position rocking curves, percent reflections, and reflection coefficients are presented. They cover the 4-24 Ǻ wavelength range and are typical of results with cleaved crystals illuminated over areas of one-half to two square inches. The energy resolution available with these crystals is shown to be nearly constant at about two-thirds of an electron volt over most of the energy range studied and the coefficient of reflection is also nearly constant at about 1 x 10-4 radians. A pronounced line-like reflectivity structure at 23.3 Ǻ is exhibited which is probably associated with oxygen atom K-shell absorption.

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First-order focusing and energy resolution optimization of a biased paracentric hemispherical spectrograph

Physics Procedia ◽

10.1016/j.phpro.2008.07.128 ◽

2008 ◽

Vol 1 (1) ◽

pp. 467-472 ◽

Cited By ~ 1

Author(s):

Omer Sise ◽

Theo J.M. Zouros ◽

Melike Ulu ◽

Mevlut Dogan

Keyword(s):

Energy Resolution ◽

First Order

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Evaluation of a monochromator with double cylindrical lenses for electron microscopy

International Journal of Modern Physics A ◽

10.1142/s0217751x19420065 ◽

2019 ◽

Vol 34 (36) ◽

pp. 1942006

Author(s):

Takashi Ogawa

Keyword(s):

Electron Microscopy ◽

Energy Resolution ◽

Simple Structure ◽

Dominant Factor ◽

Middle Plane ◽

Plane Symmetry ◽

Additional Advantage ◽

First Order ◽

High Possibility ◽

High Repeatability

In this paper, a monochromator (MC) with double cylindrical lenses (CLs) is evaluated. The MC achieved an energy resolution of 37 meV with high repeatability and stability. The double CLs realized the coincidence of the beam positions at the exit. The beam profiles were evaluated in a relative manner. Comparing two conditions with or without the MC, the beam kept equivalent sizes and showed sufficiently fine profiles. This is because the first-order aberration was a dominant factor under the experimental condition, where the second-order aberration was canceled by the middle plane symmetry of the MC optics and the beam was limited in small angles by the incident aperture. The experimental results mean that the MC with double CLs functioned properly as designed. The MC has the additional advantage of a simple structure. The results confirm that this MC has a high possibility for application to electron microscopy.

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Dual systems for all: Higher-order, role-based relational reasoning as a uniquely derived feature of human cognition

Behavioral and Brain Sciences ◽

10.1017/s0140525x19000451 ◽

2019 ◽

Vol 42 ◽

Author(s):

Daniel J. Povinelli ◽

Gabrielle C. Glorioso ◽

Shannon L. Kuznar ◽

Mateja Pavlic

Keyword(s):

Temporal Reasoning ◽

Higher Order ◽

Important Case ◽

Human Cognition ◽

Relational Reasoning ◽

Dual Systems ◽

First Order ◽

Reasoning System ◽

Role Based

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.

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Stochasting modeling of planetary ring systems

International Astronomical Union Colloquium ◽

10.1017/s025292110010154x ◽

1984 ◽

Vol 75 ◽

pp. 461-469 ◽

Cited By ~ 1

Author(s):

Robert W. Hart

Keyword(s):

Maximum Entropy ◽

Ring System ◽

The Sun ◽

Ultimate State ◽

Interparticle Interactions ◽

Ring Systems ◽

First Order ◽

Planetary Ring ◽

Insight Into

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.

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Use of LaB6 for a High Quality, Small Energy Spread Beam in an Electron Velocity Spectrometer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092633 ◽

1976 ◽

Vol 34 ◽

pp. 534-535 ◽

Cited By ~ 1

Author(s):

P. E. Batson ◽

C. H. Chen ◽

J. Silcox

Keyword(s):

High Temperature ◽

Energy Resolution ◽

Electron Velocity ◽

Electronic Excitations ◽

Small Energy ◽

Small Intensity ◽

Good Energy ◽

Spectrometer System ◽

Electron Energy Loss ◽

Very High

Electron energy loss experiments combined with microscopy have proven to be a valuable tool for the exploration of the structure of electronic excitations in materials. These types of excitations, however, are difficult to measure because of their small intensity. In a usual situation, the filament of the microscope is run at a very high temperature in order to present as much intensity as possible at the specimen. This results in a degradation of the ultimate energy resolution of the instrument due to thermal broadening of the electron beam.We report here observations and measurements on a new LaB filament in a microscope-velocity spectrometer system. We have found that, in general, we may retain a good energy resolution with intensities comparable to or greater than those available with the very high temperature tungsten filament. We have also explored the energy distribution of this filament.

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An improved magnetic prism design for a transmission electron microscope energy filter

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107344 ◽

1978 ◽

Vol 36 (1) ◽

pp. 40-41 ◽

Cited By ~ 1

Author(s):

John W. Andrew ◽

F.P. Ottensmeyer ◽

E. Martell

Keyword(s):

Energy Resolution ◽

Symmetry Plane ◽

Fringe Field ◽

Focal Distance ◽

Electron Trajectories ◽

Focusing Effect ◽

Transmission Electron ◽

Path Lengths ◽

Electron Microscopes ◽

Focusing Properties

Energy selecting electron microscopes of the Castaing-Henry prism-mirror-prism design suffer from a loss of image and energy resolution with increasing field of view. These effects can be qualitatively understood by examining the focusing properties of the prism shown in Fig. 1. A cone of electrons emerges from the entrance lens crossover A and impinges on the planar face of the prism. The task of the prism is to focus these electrons to a point B at a focal distance f2 from the side of the prism. Electrons traveling in the plane of the diagram (i.e., the symmetry plane of the prism) are focused toward point B due to the different path lengths of different electron trajectories in the triangularly shaped magnetic field. This is referred to as horizontal focusing; the better this focusing effect the better the energy resolution of the spectrometer. Electrons in a plane perpendicular to the diagram and containing the central ray of the incident cone are focused toward B by the curved fringe field of the prism.

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ELNES of Iron Compounds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133734 ◽

1990 ◽

Vol 48 (2) ◽

pp. 28-29

Author(s):

Hiroki Kurata ◽

Kazuhiro Nagai ◽

Seiji Isoda ◽

Takashi Kobayashi

Keyword(s):

Energy Loss ◽

Metal Ions ◽

Energy Resolution ◽

Transition Metal Oxides ◽

Local Symmetry ◽

Iron Compounds ◽

Fine Structures ◽

Electron Energy Loss ◽

Fe Ions ◽

Electron Energy Loss Spectra

Electron energy loss spectra of transition metal oxides, which show various fine structures in inner shell edges, have been extensively studied. These structures and their positions are related to the oxidation state of metal ions. In this sence an influence of anions coordinated with the metal ions is very interesting. In the present work, we have investigated the energy loss near-edge structures (ELNES) of some iron compounds, i.e. oxides, chlorides, fluorides and potassium cyanides. In these compounds, Fe ions (Fe2+ or Fe3+) are octahedrally surrounded by six ligand anions and this means that the local symmetry around each iron is almost isotropic.EELS spectra were obtained using a JEM-2000FX with a Gatan Model-666 PEELS. The energy resolution was about leV which was mainly due to the energy spread of LaB6 -filament. The threshole energies of each edges were measured using a voltage scan module which was calibrated by setting the Ni L3 peak in NiO to an energy value of 853 eV.

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Parallel Detection of Electron Energy Loss Spectra in Direct Mode

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134004 ◽

1990 ◽

Vol 48 (2) ◽

pp. 82-83

Author(s):

Eckhard Quandt ◽

Stephan laBarré ◽

Andreas Hartmann ◽

Heinz Niedrig

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Energy Resolution ◽

Large Angle ◽

Maximum Energy ◽

Semiconductor Detectors ◽

Parallel Detection ◽

Photodiode Arrays ◽

Electron Energy Loss ◽

Electron Energy Loss Spectra

Due to the development of semiconductor detectors with high spatial resolution -- e.g. charge coupled devices (CCDs) or photodiode arrays (PDAs) -- the parallel detection of electron energy loss spectra (EELS) has become an important alternative to serial registration. Using parallel detection for recording of energy spectroscopic large angle convergent beam patterns (LACBPs) special selected scattering vectors and small detection apertures lead to very low intensities. Therefore the very sensitive direct irradiation of a cooled linear PDA instead of the common combination of scintillator, fibre optic, and semiconductor has been investigated. In order to obtain a sufficient energy resolution the spectra are optionally magnified by a quadrupole-lens system.The detector used is a Hamamatsu S2304-512Q linear PDA with 512 diodes and removed quartz-glas window. The sensor size is 13 μm ∗ 2.5 mm with an element spacing of 25 μm. Along with the dispersion of 3.5 μm/eV at 40 keV the maximum energy resolution is limited to about 7 eV, so that a magnification system should be attached for experiments requiring a better resolution.

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