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Experimental characterization of x-ray transverse coherence in the presence of beam transport optics

Journal of Physics: conference Series 2013年第5期425卷

作者： O Chubar A Fluerasu Y S Chu L Berman L Wiegart W-K Lee J Baltser Photon Sciences Directorate Brookhaven National Laboratory Upton NY USA Niels Bohr Institute University of Copenhagen Denmark

A simple Boron fiber based interference scheme [1] and other similar schemes are currently routinely used for x-ray coherence estimation at 3rd generation synchrotron radiation sources. If such a scheme is applied after a perfect monochromator and without any focusing / transport optics in the optical path, the interpretation of the measured interference pattern is relatively straightforward and can be done in terms of the basic parameters of the source [2]. However, if the interference scheme is used after some focusing optics, e.g. close to the x-ray beam waist, the visibility of fringes can be significantly affected by the new shape of the focused beam phase-space. At the same time, optical element imperfections still have a negative impact on the transverse coherence. In such situations, which are frequently encountered in experiments at beamlines, the quantitative interpretation of a measured interference pattern is not straightforward. Here we show that this can nevertheless be done by using partially-coherent synchrotron radiation wavefront propagation simulations. The results obtained from measurements, performed at the 32-ID undulator beamline of the Advanced Photon Source, and wavefront propagation based simulations show, in particular, that new generation 1D Beryllium Compound Refractive Lenses [3, 4] do not reduce the x-ray transverse coherence in any significant manner.

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Development of Partially-Coherent Wavefront Propagation Simulation Methods for 3rd and 4th Generation Synchrotron Radiation sources

Development of Partially-Coherent Wavefront Propagation Simu...

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conference on advances in Computational Methods for x-ray optics II

作者： Chubar, Oleg Berman, Lonny Chu, Yong S. Fluerasu, Andrei Hulbert, Steve Idir, Mourad Kaznatcheev, Konstantine Shapiro, David Shen, Qun Baltser, Jana Brookhaven Natl Lab Photon Sci Directorate Upton NY 11973 USA Univ Copenhagen Niels Bohr Inst DK-2100 Copenhagen Denmark

ISBN: (纸本)9780819487513

Partially-coherent wavefront propagation calculations have proven to be feasible and very beneficial in the design of beamlines for 3rd and 4th generation Synchrotron Radiation (SR) sources. These types of calculations use the framework of classical electrodynamics for the description, on the same accuracy level, of the emission by relativistic electrons moving in magnetic fields of accelerators, and the propagation of the emitted radiation wavefronts through beamline optical elements. This enables accurate prediction of performance characteristics for beamlines exploiting high SR brightness and/or high spectral flux. Detailed analysis of radiation degree of coherence, offered by the partially-coherent wavefront propagation method, is of paramount importance for modern storage-ring based SR sources, which, thanks to extremely small sub-nanometer-level electron beam emittances, produce substantial portions of coherent flux in x-ray spectral range. We describe the general approach to partially-coherent SR wavefront propagation simulations and present examples of such simulations performed using "Synchrotron Radiation Workshop" (SRW) code for the parameters of hard x-ray undulator based beamlines at the National Synchrotron Light Source II (NSLS-II), Brookhaven National laboratory. These examples illustrate general characteristics of partially-coherent undulator radiation beams in low-emittance SR sources, and demonstrate advantages of applying high-accuracy physical-optics simulations to the optimization and performance prediction of x-ray optical beamlines in these new sources.

关键词： synchrotron radiation wave optics partial coherence

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x-ray Microbeams for Radiobiological Studies: Current Status and Future Challenges

X-ray Microbeams for Radiobiological Studies: Current Status...

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Progress in Electromagnetics Research Symposium

作者： Schettino, G. Folkard, M. Vojnovic, B. Michette, A. Prise, K. M. Queens Univ Belfast CCRCB 97 Lisburn Rd Belfast BT9 7BL Antrim North Ireland Gray Inst Radiat Oncol & Biol Oxford OX3 7DQ England Kings Coll London London WC2R 2LS England

ISBN: (纸本)9781934142127

Recent technological advances and new radiobiology challenges are behind the great interest in the use of microirradiation techniques for radiobiological studies. Radiobiological microbeams are facilities able to deliver precise doses of radiation to preselected individual cells (or part of them) in vitro and assess their biological consequences on a single cell base. They are therefore uniquely powerful tools to address specific problems where very precise targeting accuracy and dose delivery are required. The majority of radiobiological microbeams are centred on particle accelerators in order to irradiated biological samples with an exact number of ions. Currently there are only three microbeam facilities in routine use which employ focused x-rays: two are based on laboratory bench x-ray sources (Queen's University Belfast and Nagasaki University) and one developed using synchrotron x-ray beams (Photon Factory in Tsukuba, Japan). While low dose rates limit laboratory bench sources to a few keV, micronsize x-ray probes of a few tens of keV are achievable using synchrotron sources. Each facility has however their own benefits and draw back points. Techniques for focusing x-rays are well established and continuously improving with focal spots down to 50 nm achievable for ultrasoft x-rays using circular diffraction gratings known as "zone plates". Reflection x-ray optics such as Kirkpatrick-Baez mirrors and polycapillary systems are also used to produce micron size x-ray spots. Combined with nano-positioning accuracy of the new generation of stages, improved optics and image analysis algorithms, x-ray microbeams are able to address radiobiological issues in an unprecedented way. Microbeams have contributed significantly to the discovery and characterization of important new findings regarding the mechanisms of interaction of ionizing radiation with cells and tissues. In particular, they have played a fundamental role in the investigation of non-targeted effects where

关键词： Probes

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Large-scale syntheses of uniform ZnO nanorods and ethanol gas sensors application

Large-scale syntheses of uniform ZnO nanorods and ethanol ga...

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IEEE International Nanoelectronics conference (INEC)

作者： Jin Chen Jin Li Shaojun Qiu School of Materials Science and Engineering Xi''an University of Architecture and Technology Xi'an China State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi'an China Xi''an Modern Chemistry Research Institute Xi'an China

ISBN: (纸本)9781424435432;9781424435449

In this paper, we describe a low temperature, solution-based synthesis uniform ZnO nanorods with a gram scale, and their ethanol gas sensor property. The morphological, structural and optical properties of the as-prepared nanorods were investigated by means of transmission electron microscopy, high-resolution transmission electron microscopy, x-ray diffraction and photoluminescence. The results showed that the sample had uniform rod-like morphology with a narrow size distribution and highly crystallinity. Room temperature photoluminescence spectra of these nanorods show an exciton emission around 380 nm and a negligible deep-level emission, indicating the nanorods have high quality. The n-type semiconductor gas sensor properties were investigated using a side-heated type structure. The sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 400°C. Our results demonstrate the potential application of ZnO nanorods for fabricating highly sensitive gas sensors and ultraviolet laser.

关键词： Large-scale systems Zinc oxide Ethanol Gas detectors Temperature sensors Optical microscopy Transmission electron microscopy Photoluminescence Electron optics Stimulated emission

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5000 groove/mm multilayer-coated blazed grating with 33% efficiency in the 3^rd order in the EUV wavelength range

5000 groove/mm multilayer-coated blazed grating with 33% eff...

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conference on advances in x-ray/EUV optics and Components IV

作者： Voronov, Dmitriy L. Anderson, Erik H. Cambie, Rossana Salmassi, Farhad Gullikson, Eric M. Yashchuk, Valeriy V. Padmore, Howard A. Ahn, Minseung Chang, Chih-Hao Heilmann, Ralf K. Schattenburg, Mark L. Lawrence Berkeley Natl Lab 1 Cyclotron Rd Berkeley CA 94720 USA

ISBN: (纸本)9780819477385

We report on recent progress in developing diffraction gratings which can potentially provide extremely high spectral resolution of 105-106 in the EUV and soft x-ray photon energy ranges. Such a grating was fabricated by deposition of a multilayer on a substrate which consists of a 6-degree blazed grating with a high groove density. The fabrication of the substrate gratings was based on scanning interference lithography and anisotropic wet etch of silicon single crystals. The optimized fabrication process provided precise control of the grating periodicity, and the grating groove profile, together with very short anti-blazed facets, and near atomically smooth surface blazed facets. The blazed grating coated with 20 Mo/Si bilayers demonstrated a diffraction efficiency in the third order as high as 33% at an incidence angle of 11 and wavelength of 14.18 nm.

关键词： blazed grating multilayer EUV soft x-rays scanning interference lithography anisotropic etch microfabrication

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Electrochromic Nickel Oxide-based Thin Films Deposited by Chemical Bath

Electrochromic Nickel Oxide-Based Thin Films Deposited by Ch...

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3rd International conference on Smart Materials, Structures and Systems

作者： Mendoza-Galvan, A. Vidales-Hurtado, M. A. Cinvestav IPN Unidad Queretaro Queretaro 76230 Mexico

ISBN: (纸本)9783908158219

Nickel oxide-based thin films were deposited onto indium-tin oxide (ITO) coated glass substrates by the chemical bath method. The synthesis, based on the decomposition of urea in an aqueous nickel nitrate solution, promotes the deposition of the turbostratic alpha-Ni(OH)(2) phase. The electrochromic behavior of films obtained from low and high urea concentrations was tested after air annealing at temperatures of 250 and 300 degrees C. Using cyclic voltammetry, chronoamperometry and in-situ single wavelength transmittance it is shown that the films exhibit good reversibility and coloration efficiency. Transmittance spectra in the visible range show the high optical contrast of the films. It was found that in films annealed at 250 degrees C the bleached-colored switching is between the Ni(OH)(2) and beta-NiOOH phases. Films annealed at 300 degrees C are comprised by a Ni(OH)(2)-NiO mixture and Ni2O3 units or the beta-NiOOH phase are responsible for coloring depending on urea concentration in solution. The gamma-NiOOH phase was clearly identified in over-colored films. x-ray diffraction, Raman scattering, and infrared reflectance were used for phase identification.

关键词： Nickel oxide electrochromism chemical bath deposition

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Development of Polarized and Monochromatic x-ray Beams From Tube sources

Development of Polarized and Monochromatic X-Ray Beams From ...

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3rd conference on advances in x-ray/EUV optics and Components

作者： Schmitz, Robert Bingolbali, Ayhan Hussain, Abrar MacDonald, C. A. SUNY Albany Ctr Xray Opt Albany NY 12222 USA

ISBN: (纸本)9780819472977

The development of sources and optics has allowed the migration of techniques originally developed for synchrotron beam lines to field, industrial and clinical applications. For example, monochromatic beams produced with synchrotron sources are known to give higher contrast for mammography than clinical broadband sources. However, clinical sources with very narrow energy bandwidth, produced for example with flat monochromator crystals, tend to have limited intensity and field of view. Doubly curved crystal x-ray optics can provide intense focused monochromatic fan beams from laboratory x-ray tube sources. These optics are routinely employed in crystallography and x-ray fluorescence, however, careful analysis is required to assess whether the focused beam creates unacceptable divergence and hence poor spatial resolution in imaging. The intensity and resolution of the focused beam were measured and compared to simulation results. The measurements and simulations were in good agreement, allowing for system design to provide the required resolution. High efficiency collimating optics Coupled with diffracting crystals also can produce relatively high intensity and resolution. For both methods, monochromatization occurs before the patient, resulting in a potential dose reduction as well as significant measured contrast enhancement. If the diffraction angle is chosen at 90 degrees, a polarized monochromatic beam is produced. While synchrotron sources are naturally polarized, polarized beams have been less accessible for field and clinical applications. Development has begun of polarized beam sources using very low power x-ray tubes coupled to polycapillary optics. The choice of the polarizing and analyzing crystals is a tradeoff between intensity and sensitivity to depolarization effects. Intensity and rocking curve measurements have been performed with matched silicon crystals and graphite crystals.

关键词： polarized x-ray monochromatic x-ray curved crystal optics polycapillary optics imaging

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Polycapillary x-ray Microbeams

Polycapillary X-ray Microbeams

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3rd conference on advances in x-ray/EUV optics and Components

作者： Romanov, A. Yu. Inst Roentgen Opt Moscow Russia

ISBN: (纸本)9780819472977

As known, Kumakhov optics, or polycapillary optics, is based on the effective passage of x-ray radiation through the bundles of monocapillaries of various configurations;the latter takes place due to the phenomenon of total external reflection of x-rays from the inner capillary walls. In our work the basic characteristics of intense quasi-parallel x-ray polycapillary microbeams from a laboratory source in a scheme of microfocus x-ray tube/polycapillary structure, are investigated theoretically as well as experimentally. Experimental studies are carried out by means of a special automated stand. The received experimental data are compared with the results of computer statistical modeling. Modeling includes of the several theoretical models for various types of deviations of a reflection surface from ideal such as the roughness, waviness and bending. The effect of decrease of full divergence of microbeams near the exit end face of polycapillary system (quasi-decrease of divergence) is found out. But, unlike the observable effects of decrease of local divergence, proposed and discovered in works of Dabagov et al. and described on the base of surface channeling, the given effect can be well enough described within the lit-nits of geometrical optics. Now oil the base of Kumakhov optics at the Institute for Roentgen optics the new generation of devices is developed and created: "daboratory synchrotron", fluorescent spectrometers, reflectometers, diffractometers, x-ray microscopes and combinations of several devices in one.

关键词： x-ray microbeams Kumakhov optics polycapillary optics x-ray analytical instruments laboratory synchrotron

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Innovative approaches to surface sensitive analysis techniques on the basis of plasma-based off-synchrotron xUV/EUV light sources

Innovative approaches to surface sensitive analysis techniqu...

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3rd conference on advances in x-ray/EUV optics and Components

作者： Banyay, Matus Juschkin, Larissa Rhein Westfal TH Aachen Dept Opt Syst Technol Steinbachstr 15 D-52074 Aachen Germany JARA Fundamentals Future Informat Technol Julich Germany

ISBN: (纸本)9780819472977

The use of extreme ultraviolet radiation (xUV/EUV) enables a variety of new optical and analytical techniques such as EUV-lithography, -microscopy, but, also -reflectometry. Due to the strong interaction of xUV with matter, grazing-incidence reflectometry in the 1-40 nm range has proven to be a surface sensitive technique to characterize thin-film structures oil the nanometer scale. Chemical composition, thickness and surface roughness of a deposited layer system call be determined indirectly from its reflectivity curve by, non-linear regression techniques and the combined Nevot Croce- and general transfer matrix formalism for x-ray reflectivity. Here the reflectivity can either be determined as a, function of incident wavelength at a, fixed grazing angle or vice versa. This way it is even possible to specify a root-mean-square (rms) surface roughness of hidden layer-interfaces in the depth of a stack. To date, such measurements in the xUV have only been carried out at synchrotron facilities prohibiting ail easy access to a broad range of users. Taking into account the recent progress in the development of short wavelength sources and optics, laboratory-scale, plasma-based xUV light-sources are becoming ail attractive option for compact devices. Along with our simulations we present our experimental work oil an off-synchrotron xUV-reflectometer for characterization of thin-film structures. The device can also be utilized to carry out, scattered light measurements from ultra smooth surfaces, e.g. wafers, for defect inspection.

关键词： Extreme Ultraviolet xUV EUV Reflectometry Grazing Incidence Thin-Films

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Crystal Quality Analysis and Improvement Using x-ray Topography

Crystal Quality Analysis and Improvement Using X-ray Topogra...

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3rd conference on advances in x-ray/EUV optics and Components

作者： Maj, J. A. Goetze, K. Macrander, A. T. Zhong, Y. C. Huang, x. R. Maj, L. Argonne Natl Lab 9700 S Cass Ave Argonne IL 60439 USA Univ Chicago Chicago IL 60637 USA

ISBN: (纸本)9780819472977

The Topography x-ray laboratory of the Advanced Photon Source (APS) at Argonne National laboratory operates as a collaborative effort with APS users to produce high performance crystals for APS x-ray beamline experiments. For many years the topography laboratory has worked closely with an on-site optics shop to help ensure the production of crystals with the highest quality, most stress-free surface finish possible. It has been instrumental in evaluating and refining methods used to produce high quality crystals. Topographical analysis has shown to be an effective method to quantify and determine the distribution of stresses, to help identify methods that would mitigate the stresses and improve the Rocking curve, and to create CCD images of the crystal. This paper describes the topography process and offers methods for reducing crystal stresses in order to substantially improve the crystal optics.

关键词： Crystals x-rays Silicon Crystal optics Laser crystals Monochromators Surface finishing Diamond Photonic crystals Germanium

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