scholarly journals Hard X-ray induced fast secondary electron cascading processes in solids

2018 ◽  
Vol 113 (11) ◽  
pp. 114102 ◽  
Author(s):  
K. Mecseki ◽  
H. Höppner ◽  
M. Büscher ◽  
V. Tkachenko ◽  
N. Medvedev ◽  
...  
Keyword(s):  
Secondary Electron ◽  
X Ray ◽  
Cascading Processes

Electron behavior in the gaseous environment of the ESEM chamber

1996 ◽  
Vol 54 ◽  
pp. 838-839 ◽  
Author(s):  
S.A. Wight
Keyword(s):  
Secondary Electron ◽  
High Vacuum ◽  
Beam Current ◽  
Chamber Pressure ◽  
Environmental Scanning ◽  
Carbon Block ◽  
Faraday Cup ◽  
X Ray ◽  
Gaseous Environment ◽  
Working Distance

Measurements of electrons striking the sample in the Environmental Scanning Electron Microscope (ESEM) are needed to begin to understand the effect of the presence of the gas on analytical measurements. Accurate beam current is important to x-ray microanalysis and it is typically measured with a faraday cup. A faraday cup (Figure 1) was constructed from a carbon block embedded in non-conductive epoxy with a 45 micrometer bore platinum aperture over the hole. Currents were measured with an electrometer and recorded as instrument parameters were varied.Instrument parameters investigated included working distance, chamber pressure, condenser percentage, and accelerating voltage. The conditions studied were low vacuum with gaseous secondary electron detector (GSED) voltage on; low vacuum with GSED voltage off; and high vacuum (GSED off). The base conditions were 30 kV, 667 Pa (5 Torr) water vapor, 100,000x magnification with the beam centered inside aperture, GSED voltage at 370 VDC, condenser at 50%, and working distance at 19.5 mm. All modifications of instrument parameters were made from these conditions.

CuOX Films for NO2 Detection: Microstructural Characterization

2013 ◽  
Vol 481 ◽  
pp. 133-136 ◽  
Author(s):  
T.N. Myasoedova ◽  
G.E. Yalovega ◽  
N.K. Plugotarenko ◽  
M. Brzhezinskaya ◽  
V.V. Petrov ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Secondary Electron ◽  
Operating Temperature ◽  
Sol Gel ◽  
Microstructural Characterization ◽  
Temperature Treatment ◽  
Copper Oxides ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

Copper oxides films as promising materials for gas sensors applications were studied. Copper oxide films were deposited onto Si/SiO2substrates using a citrate sol-gel method with the subsequent temperature treatment at 150-5000C. These films were characterized by means of secondary electron microscopy (SEM) and X-ray-absorption near-edge structure (XANES) spectroscopy. The prepared films were utilized in NO2sensors. The dependences of the NO2response on the operating temperature and NO2concentration (10-200 ppm) were investigated. The maximum NO2response was achieved for the film annealed at 2500C.

scholarly journals X-Ray Spectra of Solar Active Regions

1975 ◽  
Vol 68 ◽  
pp. 45-64 ◽  
Author(s):  
John H. Parkinson
Keyword(s):  
Spectral Resolution ◽  
Active Regions ◽  
X Ray ◽  
Quantitative Theory ◽  
Great Progress ◽  
Solar Active Regions ◽  
Cascading Processes ◽  
Weak Satellite

The last few years have seen great progress in our understanding of X-ray spectra of solar active regions. This paper demonstrates both the usefulness and the limitations of the techniques, both scientific and instrumental, that have recently become available. Improvements in spectral resolution led to the discovery of weak satellite lines to helium-like ions; the quantitative theory for these lines is also discussed. The observed intensities of the Fe XVII lines are also investigated and found to be in agreement with calculations that allow for cascading processes.

scholarly journals Spectral Index Versus Frequency and Models for the Continua of AGN and QSOs

1989 ◽  
Vol 134 ◽  
pp. 201-202
Author(s):  
Wayne A. Stein
Keyword(s):  
Accretion Disk ◽  
Spectral Index ◽  
Power Law ◽  
Spectral Distribution ◽  
Secondary Electron ◽  
Low Frequency ◽  
Spectral Indices ◽  
Ultraviolet Continuum ◽  
Electron Synchrotron ◽  
X Ray

The observed spectral index as a function of frequency of QSO continua must be explained in models. It is generally increasing (F(ν) ∝ ν−α, α increasing) with higher frequency in the infrared (downward curvature). The visual to ultraviolet continuum has been shown to be a broken power law with F(ν) ∝ ν−0.5 at low frequency and a break to larger α at νo ∼ 3×1015 Hz. X-ray observations frequently exhibit a flat continuum with α < 1. One prominent example is 3C273 for which α1–3μm → 2, αvis ∼ 0.5 and αx ∼ 0.5. These spectral indices arise naturally in Secondary Electron Synchrotron Self-Compton (SESSC) models. Some accretion disk models approach these spectral indices for the visual-ultraviolet portion of the spectral distribution.

Soft x‐ray analysis system for reflection, secondary electron, and fluorescence spectroscopy

1989 ◽  
Vol 60 (7) ◽  
pp. 2219-2222 ◽  
Author(s):  
Y. Hirai ◽  
I. Waki ◽  
A. Momose ◽  
K. Hayakawa
Keyword(s):  
Fluorescence Spectroscopy ◽  
Secondary Electron ◽  
X Ray ◽  
Analysis System

A comparison of X-ray and proton beam low energy secondary electron track structures using the low energy models of Geant4

2011 ◽  
Vol 88 (1-2) ◽  
pp. 164-170 ◽  
Author(s):  
Aimee L. McNamara ◽  
Susanna Guatelli ◽  
Dale A. Prokopovich ◽  
Mark I. Reinhard ◽  
Anatoly B. Rosenfeld
Keyword(s):  
Proton Beam ◽  
Secondary Electron ◽  
Low Energy ◽  
X Ray ◽  
Energy Models ◽  
Electron Track

Thickness of carbon coatings on silicon materials determined by hard X-ray photoelectron spectroscopy at multiple photon energies

2019 ◽  
Vol 26 (6) ◽  
pp. 1936-1939 ◽  
Author(s):  
Noritake Isomura ◽  
Naoko Takahashi ◽  
Satoru Kosaka ◽  
Hiroyuki Kawaura
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Secondary Electron ◽  
Lithium Ion ◽  
Cross Sectional ◽  
Carbon Coatings ◽  
X Ray ◽  
Negative Electrodes ◽  
Silicon Materials ◽  
Microscopy Images

Hard X-ray photoelectron spectroscopy at multiple photon energies is used to investigate the surface structure of carbon coatings on silicon materials destined for use as negative electrodes in lithium-ion batteries. The photoelectron intensity from the carbon coatings decreases with an increase in the kinetic energy of the photoelectron. By fitting the photoelectron intensity versus energy to numerically derived curves, the thickness and coverage of the carbon coatings can be obtained. The results are in agreement with the values suggested by the cross-sectional secondary-electron microscopy images of the carbon coatings, although the thickness should be corrected by accounting for the rectangular parallelepiped structure of the silicon material.

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