scholarly journals Mirrored low-energy channel for the MiniXRD

2015 ◽  
Author(s):  
E. C. Dutra ◽  
L. P. MacNeil ◽  
S. M. Compton ◽  
B. A. Jacoby ◽  
M. L. Raphaelian
Keyword(s):  
Low Energy ◽  
Energy Channel

Fragmentations des cétones aliphatiques métastables. II. Compétition entre éliminations de radicaux hydrocarbonés et d'alcanes.

1982 ◽  
Vol 60 (16) ◽  
pp. 2107-2112 ◽  
Author(s):  
Guy Bouchoux ◽  
Yannik Hoppilliard
Keyword(s):  
Molecular Ions ◽  
Low Energy ◽  
Final States ◽  
Energy Channel ◽  
Aliphatic Ketones ◽  
Thermochemical Stability

The fragmentation of the metas table molecular ions of six aliphatic ketones is studied. The ion fragment abundances [M – R•] and [M–RH] (R• being a lateral radical) can be predicted from the thermochemical stability of the corresponding final states. Exceptions to this behavior are found for metastable molecular ions of methylethylketone and methylisopropylketone where it is demonstrated that the lifetime of these ions is too short to permit significant decompositions via the low energy channel after 10−5 s.

A Low-Energy Channel-Multiplier Spectrometer for ATS-E

1969 ◽  
Vol 16 (1) ◽  
pp. 359-370 ◽  
Author(s):  
R. D. Reed ◽  
E. G. Shelley ◽  
J. C. Bakke ◽  
T. C. Sanders ◽  
J. D. McDaniel
Keyword(s):  
Low Energy ◽  
Energy Channel

scholarly journals Electrostatic interaction between Interball-2 and the ambient plasma. 2. Influence on the low energy ion measurements with Hyperboloid

2002 ◽  
Vol 20 (3) ◽  
pp. 377-390 ◽  
Author(s):  
M. Hamelin ◽  
M. Bouhram ◽  
N. Dubouloz ◽  
M. Malingre ◽  
S. A. Grigoriev ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Low Energy ◽  
Solar Panels ◽  
Ion Distribution ◽  
Energy Channel ◽  
Ambient Plasma ◽  
Ion Distributions ◽  
Wind Events ◽  
Low Energy Ions ◽  
Satellite Potential

Abstract. The measurement of the thermal ion distributions in space is always strongly influenced by the ion motion through the complex 3D electrostatic potential structure built around a charged spacecraft. In this work, we study the related aberrations of the ion distribution detected on board, with special application to the case of the Hyperboloid instrument borne by the Interball-2 auroral satellite. Most of the time, the Interball-2 high altitude auroral satellite is charged at some non-negligible positive potential with respect to the ambient plasma, as shown in part 1; in consequence, the measurement of magnetospheric low energy ions (< 80 eV) with the Hyperboloid instrument can be disturbed by the complex electric potential environment of the satellite. In the case of positive charging, as in previous experiments, a negative bias is applied to the Hyperboloid structure in order to reduce this effect and to keep as much as possible the opportunity to detect very low energy ions. Then, the ions reaching the Hyperboloid entrance windows would have travelled across a continuous huge electrostatic lens involving various spatial scales from ~ 10 cm (detector radius) to ~ 10 m (satellite antennas). Neglecting space charge effects, we have computed the ion trajectories that are able to reach the Hyperboloid windows within their acceptance angles. There are three main results: (i) for given values of the satellite potential, and for each direction of arrival (each window), we deduced the related energy cutoff; (ii) we found that all ions in the energy channel, including the cutoff, can come from a large range of directions in the unperturbed plasma, especially when the solar panels or antennas act as electrostatic mirrors; (iii) for higher energy channels, the disturbances are reduced to small angular shifts. Biasing of the aperture is not very effective with the Hyperboloid instrument (as on previous missions with instruments installed close to the spacecraft body) because the potential environment is driven by effects from the spacecraft. Our results are used to explain some unexpected features of the low energy ion measurements, especially during polar wind events recorded by Hyperboloid. In conclusion, knowing the satellite potential from IESP measurements, we were able to reject any low energy doubtful data and to perform angular corrections for all higher energy ion data. Then the selected and corrected data are a reliable basis for interpretation and estimation of the thermal ion distributions.Key words. Space plasma physics (charged particle motion and acceleration; numerical simulation studies; spacecraft sheaths, wakes, charging)

Low-energy channel for mass transfer in Pt crystal initiated by molecule impact

2019 ◽  
Vol 163 ◽  
pp. 248-255 ◽  
Author(s):  
Rita I. Babicheva ◽  
Iman Evazzade ◽  
Elena A. Korznikova ◽  
Igor A. Shepelev ◽  
Kun Zhou ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Low Energy ◽  
Energy Channel

scholarly journals Tryptophan-75 is a Low Energy Channel Gating Residue that Facilitates Substrate Egress/Access in Cytochrome P450 2D6

2020 ◽  
pp. DMD-AR-2020-000274
Author(s):  
Kevin D. McCarty ◽  
Samuel A. Ratliff ◽  
Kyle A. Furge ◽  
Laura Lowe Furge
Keyword(s):  
Cytochrome P450 ◽  
Channel Gating ◽  
Low Energy ◽  
Cytochrome P450 2D6 ◽  
Energy Channel ◽  
P450 2D6

Calibration of the low-energy channel Thomson parabola of the LMJ-PETAL diagnostic SEPAGE with protons and carbon ions

2018 ◽  
Vol 89 (2) ◽  
pp. 023304 ◽  
Author(s):  
J.-E. Ducret ◽  
D. Batani ◽  
G. Boutoux ◽  
A. Chancé ◽  
B. Gastineau ◽  
...  
Keyword(s):  
Low Energy ◽  
Carbon Ions ◽  
Energy Channel

Dissociated Σ=27 boundaries in silicon

1988 ◽  
Vol 46 ◽  
pp. 624-625
Author(s):  
A. Garg ◽  
W.A.T. Clark ◽  
J.P. Hirth
Keyword(s):  
Electron Diffraction ◽  
Local Minimum ◽  
Boundary Energy ◽  
Coincidence Site Lattice ◽  
Boundary Plane ◽  
Low Energy ◽  
Theoretical Understanding ◽  
Site Lattice ◽  
Kikuchi Pattern ◽  
Analysis Techniques

In the last twenty years, a significant amount of work has been done in the theoretical understanding of grain boundaries. The various proposed grain boundary models suggest the existence of coincidence site lattice (CSL) boundaries at specific misorientations where a periodic structure representing a local minimum of energy exists between the two crystals. In general, the boundary energy depends not only upon the density of CSL sites but also upon the boundary plane, so that different facets of the same boundary have different energy. Here we describe TEM observations of the dissociation of a Σ=27 boundary in silicon in order to reduce its surface energy and attain a low energy configuration.The boundary was identified as near CSL Σ=27 {255} having a misorientation of (38.7±0.2)°/[011] by standard Kikuchi pattern, electron diffraction and trace analysis techniques. Although the boundary appeared planar, in the TEM it was found to be dissociated in some regions into a Σ=3 {111} and a Σ=9 {122} boundary, as shown in Fig. 1.

Transfer optics for high spatial resolution electron spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 666-667
Author(s):  
G. G. Hembree ◽  
Luo Chuan Hong ◽  
P.A. Bennett ◽  
J.A. Venables
Keyword(s):  
Magnetic Field ◽  
Scanning Transmission Electron Microscope ◽  
Low Energy ◽  
Objective Lens ◽  
State University ◽  
Arizona State University ◽  
Initial Field ◽  
Resolution Electron ◽  
Scanning Transmission ◽  
Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 354-355
Author(s):  
Bertholdand Senftinger ◽  
Helmut Liebl
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Strength ◽  
Numerical Aperture ◽  
Low Energy ◽  
Energy Electron ◽  
High Resolution Imaging ◽  
Lens System ◽  
Resolution Imaging ◽  
Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

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