Output beam polarisation of x-ray lasers with transient inversion

A prototype of a new double crystal monochromator (DCM) has been designed and developed for the second crystallography beamline (XRD2) at ELETTRA. The new device has to cover the 8–35 keV X-ray range. Since the corresponding diffraction angles are quite small, the choice has been to design a DCM with a fixed distance between the two crystals. As a consequence, the output beam has a small vertical displacement during the scan. This movement is compensated by means of an upstream mask, vertically moving and cutting the input beam at different heights. The movement of the mask is driven by a mechanism linked to the primary rotation of crystals (self-compensation), without any additional motor and following the displacement law required for compensation. The principle, the mechanism and the general mechanical concept of the device will be described in this paper.

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Single Reflection Method for Pole-Density Measurements Accounting for Secondary Extinction in Textured Films

Materials Science Forum ◽

10.4028/www.scientific.net/msf.443-444.141 ◽

2004 ◽

Vol 443-444 ◽

pp. 141-144

Author(s):

I. Tomov

Keyword(s):

Experimental Verification ◽

Pole Density ◽

Reflection Method ◽

Density Measurements ◽

X Ray ◽

Diffraction Angle ◽

Pair Method ◽

Secondary Extinction ◽

Beam Polarisation

A method of pole density measurements is described, which uses the differences in X-ray beam polarisation of two monochromators. The method requires a single reflection at an intermediate diffraction angle. Experimental verification is provided by pole density measurements of Ag films and comparison the results obtained with the proposed method with results from the reflection-pair method [8-10].

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Application of Tapered Monocapillary in a Laboratory Mxrf Set-Up

Advances in X-ray Analysis ◽

10.1154/s0376030800022473 ◽

1995 ◽

Vol 39 ◽

pp. 81-86

Author(s):

N. Gao ◽

I. Ponomarev ◽

Q. F. Xiao ◽

W. M. Gibson ◽

D. A. Carpenter

Keyword(s):

Experimental Work ◽

High Energy ◽

X Rays ◽

Output Beam ◽

Bremsstrahlung Radiation ◽

X Ray ◽

Set Up

Simulation and experimental work that compare the performance of straight and tapered monocapillaries when used with laboratory x-ray sources are reported. Detailed simulations for various taper profiles give several important conclusions for optimizing the design of a tapered monocapillary. Several tapered monocapillaries were prepared. With a 16W x-ray source, beam intensities of 4×105 photon/sec/μm2 and 3×105photon/sec/μm2 of Cu Kα x rays were obtained from the tapered monocapillaries for output diameters of 8μm and 3.5μm, respectively. These intensities are 1.4 and 1.5 times that obtained from straight capillaries with the same output beam sizes at the experimental set-up optimized for a straight capillary. In addition to the gain in x-ray flux, the tapered monocapillaries produce output beams with significantly reduced high energy bremsstrahlung radiation and increased flux stability with respect to shifts of the x-ray source spot.

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Phase-space matching between bent Laue and flat Bragg crystals

Journal of Synchrotron Radiation ◽

10.1107/s1600577519010774 ◽

2019 ◽

Vol 26 (6) ◽

pp. 1917-1923

Author(s):

Z. Zhong ◽

M. Hasnah ◽

A. Broadbent ◽

E. Dooryhee ◽

M. Lucas

Keyword(s):

Phase Space ◽

Dark Field ◽

Output Beam ◽

Combined System ◽

Double Crystal ◽

X Ray ◽

Dark Field Imaging ◽

Diffraction Enhanced Imaging ◽

Analyzer Based Imaging ◽

Field Imaging

Through phase-space analysis of Dumond diagrams for a flat Bragg crystal, a single bent Laue crystal and a monochromator consisting of double-bent Laue crystals, this work shows that it is possible to match the flat Bragg crystal to both the single-crystal and double-crystal Laue monochromators. The matched system has the advantage that the phase space of the bent crystal's output beam is much larger than that of the flat crystal, making the combined system stable. Here it is suggested that such a matched system can be used at synchrotron facilities to realize X-ray dark-field imaging, analyzer-based imaging and diffraction-enhanced imaging at beamlines using double-Laue monochromators.

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Exploiting the potential of beam-compressing channel-cut monochromators for laboratory high-resolution small-angle X-ray scattering experiments

Journal of Applied Crystallography ◽

10.1107/s1600576719003674 ◽

2019 ◽

Vol 52 (3) ◽

pp. 498-506 ◽

Cited By ~ 1

Author(s):

Peter Nádaždy ◽

Jakub Hagara ◽

Matej Jergel ◽

Eva Majková ◽

Petr Mikulík ◽

...

Keyword(s):

High Resolution ◽

Small Angle ◽

Beam Quality ◽

Photon Flux ◽

Beam Parameter ◽

Output Beam ◽

X Ray ◽

X Ray Scattering ◽

Maximum Photon ◽

Ray Scattering

A systematic study of beam-compressing monolithic channel-cut monochromators (CCMs) with a V-shaped channel was performed. The CCMs were optimized in terms of a chosen output beam parameter for exploitation in laboratory high-resolution small-angle X-ray scattering (SAXS) and grazing-incidence SAXS (GISAXS) experiments. Ray-tracing simulations provided maps of particular Ge(220) CCM output beam parameters over the complete set of asymmetry angles of the two CCM diffractions. This allowed the design and fabrication of two dedicated CCMs, one optimized for maximum photon flux per detector pixel and the other for Kα2 suppression. The output beam quality was tested in SAXS/GISAXS experiments on a commercial setup with a liquid-metal-jet Ga microfocus X-ray source connected to 2D collimating Montel optics. The performance of the CCM optimized for maximum photon flux per detector pixel was limited by the quality of the inner channel walls owing to a strongly asymmetric design. However, the CCM optimized for Kα2 suppression exhibited an excellent resolution of 314 nm in real space. This was further enhanced up to 524 nm by a parallel Ge(220) CCM in the dispersive configuration at a still applicable output flux of 3 × 106 photon s−1. The 314 nm resolution outperforms by more than 2.5× the upper resolution limit of the same setup with a pinhole collimator instead of the CCM. Comparative SAXS measurements on the same setup with a Kratky block collimator as an alternative to the CCM showed that the CCM provided more than one order higher transmittance at a comparable resolution or twice higher resolution at a comparable transmittance. These results qualify CCMs for a new type of integrated reflective–diffractive optics consisting of Göbel mirrors and V-shaped CCMs for the next generation of high-performance microfocus laboratory X-ray sources.

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PLASMA DYNAMICS IN ACCELERATOR WITH PLASMA OPENING SWITCH

10.46813/2019-124-077 ◽

2019 ◽

pp. 77-80

Author(s):

O.S. Druj ◽

V.V. Yegorenkov ◽

I.M. Onyshchenko ◽

V.B. Yuferov

Keyword(s):

Electron Accelerator ◽

Plasma Channel ◽

Output Beam ◽

Plasma Dynamics ◽

X Ray ◽

Plasma Opening Switch ◽

Opening Switch ◽

Switch Operation ◽

Plasma Compression ◽

The Moment

Plasma propagation in the pulse electron accelerator chamber with a plasma opening switch is investigated. Output beam and X-ray radiation parameters are shown to vary depending on the plasma channel location at the moment of current breaking. Experiments showing plasma compression into channels during the conductive phase of the plasma opening switch operation have been performed.

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

International Astronomical Union Colloquium ◽

10.1017/s0252921100025446 ◽

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.

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Some Problems in Understanding the Solar Corona

International Astronomical Union Colloquium ◽

10.1017/s025292110002491x ◽

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.

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White-Light Coronal Structures: Streamers and CMEs

International Astronomical Union Colloquium ◽

10.1017/s0252921100025045 ◽

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.

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