scholarly journals X-ray-based displacement measurement for hostile environments

1992 ◽  
Vol 32 (4) ◽  
pp. 289-295 ◽  
Author(s):  
H. A. Canistraro ◽  
E. H. Jordan ◽  
D. M. Pease
Keyword(s):  
Displacement Measurement ◽  
X Ray ◽  
Hostile Environments

Differential displacement measurement using scanning x-ray beams

1998 ◽  
Vol 69 (2) ◽  
pp. 452-456 ◽  
Author(s):  
Howard A. Canistraro ◽  
Eric H. Jordan ◽  
Douglas M. Pease
Keyword(s):  
Displacement Measurement ◽  
X Ray

High-Temperature Displacement Measurement Using a Scanning Focussed X-Ray Line Source

1991 ◽  
pp. 223-230
Author(s):  
E. H. Jordan ◽  
H. A. Canistraro ◽  
D. M. Pease ◽  
D. Brewe
Keyword(s):  
High Temperature ◽  
Line Source ◽  
Displacement Measurement ◽  
X Ray

High-Temperature Displacement Measurement Using a Scanning Focused X-ray Line Source

1990 ◽  
Vol 34 ◽  
pp. 223-230
Author(s):  
E. H. Jordan ◽  
H. A. Canistraro ◽  
D. M. Pease ◽  
D. Brewe
Keyword(s):  
Relative Displacement ◽  
Measuring System ◽  
Secondary Radiation ◽  
X Rays ◽  
Pressure Gradients ◽  
Ambient Conditions ◽  
Radiation Level ◽  
X Ray ◽  
Adverse Conditions ◽  
Hostile Environments

AbstractA non-contacting displacement measuring system utilizing focussed x-rays is being developed for use in hostile environments. Ultimately, this method will be used to measure mechnical strain under adverse conditions such as high temperatures, flame, cutting fluids, and gases with high velocity and pressure gradients. The foundation of the technique is the use of xrays, which are immune to the various environmental factors mentioned above. The proposed system uses a highly focussed, intense x-ray line which is scanned across markers that fluoresce secondary radiation. This secondary radiation level is then monitored using a photon detector and marker-focussed line overlap can be discerned. These targets can be used as fiducial markers demarcating a gage length, and the change in pointing angle of the focussed beam at target overlap is used as a measure of relative displacement. The present experimental systemcan consistently resolve 1.27 microns at ambient conditions, and 2.54 microns have been measured at a target temperature of 1900 de-grees F through an open flame. Given the performance of the current apparatus, equipment improvements should permit increases in resolution by a least a factor of 10 and measurements at much higher temperatures are possible.

A Solid State X-Ray Fluorescence Analyzer for Use in Hostile Environments

1969 ◽  
Vol 16 (1) ◽  
pp. 432-435 ◽  
Author(s):  
P. A. Johnston ◽  
G. C. Huth ◽  
R. J. Locker
Keyword(s):  
Solid State ◽  
X Ray ◽  
Hostile Environments ◽  
Fluorescence Analyzer

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

Some Problems in Understanding the Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel
Keyword(s):  
Solar Corona ◽  
Solar Atmosphere ◽  
Theoretical Modelling ◽  
Total System ◽  
Major Advance ◽  
X Ray ◽  
Proper Perspective ◽  
Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Iron K-Line Emission from X-Ray Binaries

1988 ◽  
Vol 102 ◽  
pp. 47-50
Author(s):  
K. Masai ◽  
S. Hayakawa ◽  
F. Nagase
Keyword(s):  
Accretion Disk ◽  
Radiative Recombination ◽  
Characteristic Temperature ◽  
Line Emission ◽  
Ionization Front ◽  
Continuum Radiation ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

AbstractEmission mechanisms of the iron Kα-lines in X-ray binaries are discussed in relation with the characteristic temperature Txof continuum radiation thereof. The 6.7 keV line is ascribed to radiative recombination followed by cascades in a corona of ∼ 100 eV formed above the accretion disk. This mechanism is attained for Tx≲ 10 keV as observed for low mass X-ray binaries. The 6.4 keV line observed for binary X-ray pulsars with Tx> 10 keV is likely due to fluorescence outside the He II ionization front.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

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