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AbstractAbstract
[en] A Fresnel zone plate (FZP) with 35 nm outermost zone width has been fabricated and tested in the hard X-ray region. The FZP was made by electron beam lithography and reactive ion etching technique. The performance test of the FZP was carried out by measuring the focused beam profile for coherent hard X-ray beam at the beamline 20XU of Spring-8. The full width at half maximum of the focused beam profile measured by knife-edge scan method is 34.9±2.7 nm, that agrees well with the theoretical value of diffraction-limited resolution. Applications to scanning microscopy were also carried out
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 6
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[en] We have developed a new CCD-based radiographic camera called Crystal Eye Cam for use in shock physics experiments: it is composed of two turning mirrors and an objective to relay the (visible) image from a scintillator assembly to a highly sensitive, low noise CCD camera. The objective was specifically developed to match our needs and has few chromatic and geometric aberrations and high photometric performance. The scintillator assembly is constructed using a specific (patented) technique of assembling monolithic scintillating crystals. It replaces the segmented scintillator previously used at our facility and produces higher quality images (better resolution and no segmentation). The sensitivity, noise level, detection threshold and resolution of Crystal Eye Cam were measured using an 18-MeV-Bremsstrahlung spectrum, filtered with 10 cm of lead, and two 165 mm x 165 mm BGO assemblies: 20 and 30 mm in thickness, respectively. In particular, with the 30 mm-thick BGO assembly, the measured detection threshold of the imager (at SNR0=2) is 1μ Gy(air) and its resolution is ∼1 mm. For 4-MeV incident photons, the estimated (energy) stopping power of the scintillator is 41%. The scintillator assembly thus proved to be a cheaper, effective alternative to segmented scintillators for use in Crystal Eye Cam.
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Journal Article
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 9
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[en] Focusing X-ray telescopes have been the most important factor in X-ray astronomy ascent to equality with optical and radio astronomy. They are the prime tool for studying thermal emission from very high temperature regions, non-thermal synchrotron radiation from very high energy particles in magnetic fields and inverse Compton scattering of lower energy photons into the X-ray band. Four missions with focusing grazing incidence X-ray telescopes based upon the Wolter 1 geometry are currently operating in space within the 0.2 to 10 keV band. Two observatory class missions have been operating since 1999 with both imaging capability and high resolution dispersive spectrometers. They are NASAs Chandra X-ray Observatory, which has an angular resolution of 0.5 arc seconds and an area of 0.1 m2 and ESAs XMM-Newton which has 3 co-aligned telescopes with a combined effective area of 0.43 m2 and a resolution of 15 arc seconds. The two others are Japan is Suzaku with lower spatial resolution and non-dispersive spectroscopy and the XRT of Swift which observes and precisely positions the X-ray afterglows of gamma-ray bursts. New missions include focusing telescopes with much broader bandwidth and telescopes that will perform a new sky survey. NASA, ESA, and Japan is space agency are collaborating in developing an observatory with very large effective area for very high energy resolution dispersive and non-dispersive spectroscopy. New technologies are required to improve upon the angular resolution of Chandra. Adaptive optics should provide modest improvement. However, orders of magnitude improvement can be achieved only by employing physical optics. Transmitting diffractive-refractive lenses are capable theoretically of achieving sub-milli arc second resolution. X-ray interferometry could in theory achieve 0.1 micro arc second resolution, which is sufficient to image the event horizon of super massive black holes at the center of nearby active galaxies. However, the physical optics systems have focal lengths in the range 103 to 104 km and cannot be realized until the technology for accurately positioned long distance formation flying between optics and detector is developed.
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 19
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[en] An overview is given of the study on X-ray focusing using the Fabry-Perot type multi-plate silicon crystal cavities consisting of compound refractive lenses. Silicon (12 4 0) is used as the back reflection for cavity resonance at the photon energy of 14.4388 keV. Measurements of focal length of the transmitted beam through the crystal cavities show enhanced focusing effect due to the presence of back diffraction. Also, an incident beam with ultrahigh energy resolution can improve the focusing owing to the wider acceptance angle of the back diffraction. Considerations based on the excitation of dispersion surface within the framework of X-ray dynamical diffraction theory are also presented to reveal the origin of this enhanced focusing
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Journal Article
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 7
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BOSONS, BREMSSTRAHLUNG, COHERENT SCATTERING, DIFFERENTIAL EQUATIONS, DIFFRACTION, ELECTROMAGNETIC RADIATION, ELEMENTARY PARTICLES, ELEMENTS, ENERGY RANGE, EQUATIONS, INTERFEROMETERS, KEV RANGE, MASSLESS PARTICLES, MEASURING INSTRUMENTS, OPTICAL PROPERTIES, PARTIAL DIFFERENTIAL EQUATIONS, PHYSICAL PROPERTIES, RADIATIONS, REFLECTION, SCATTERING, SEMIMETALS, SURFACE PROPERTIES
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[en] This paper describes the design, crystal selection, and crystal testing for a vertical Johann spectrometer operating in the 13 keV range to measure ion Doppler broadening in inertial confinement plasmas. The spectrometer is designed to use thin, curved, mica crystals to achieve a resolving power of E/δE>2000. A number of natural mica crystals were screened for flatness and X-ray diffraction width to find samples of sufficient perfection for use in the instrument. Procedures to select and mount high quality mica samples are discussed. A diode-type X-ray source coupled to a dual goniometer arrangement was used to measure the crystal reflectivity curve. A procedure was developed for evaluating the goniometer performance using a set of diffraction grade Si crystals. This goniometer system was invaluable for identifying the best original crystals for further use and developing the techniques to select satisfactory curved crystals for the spectrometer
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 10
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[en] The UK Smart X-Ray Optics (SXO) programme is developing active/adaptive optics for terrestrial applications. One of the technologies proposed is micro structured optical arrays (MOAs), which focus X-rays using grazing incidence reflection through consecutive aligned arrays of microscopic channels. Although such arrays are similar in concept to poly capillary and microchannel plate optics, they can be bent and adjusted using piezoelectric actuators providing control over the focusing and inherent aberrations. Custom configurations can be designed, using ray tracing and finite element analysis, for applications from sub-keV to several-keV X-rays, and the channels of appropriate aspect ratios can be made using deep silicon etching. An exemplar application will be in the micro probing of biological cells and tissue samples using Ti Ka radiation (4.5?keV) in studies related to radiation-induced cancers. This paper discusses the optical design, modelling, and manufacture of such optics
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2011(2011); p. 15
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[en] Total-external-reflection Kirkpatrick-Baez mirror optics for high-energy X-rays have been applied to the X-ray microprobe at beamline 37XU of SPring-8. A focused beam size of 1.0 μm inductively-coupled plasma mass spectrometry). (V) X0.83 μm (H) has been achieved at an X-ray energy of 30 keV, and a total photon flux of the focused beam was about 5x109 photons/s. Micro-X-ray fluorescence (μ-XRF) analysis of the uranium distribution in rat kidneys has been performed with the mirror-focused beam. The sensitivity of uranium was evaluated from the XRF intensity of thin standard samples, and the minimum detection limit was estimated at 10 μg/g. The high-spatial-resolution analysis revealed that uranium was concentrated in the epithelium of the proximal tubules in the inner cortex. The maximum concentration of uranium in the tubule was estimated to be 503μg/g using a semiquantitative evaluation.
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 5
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[en] Thin foil mirrors were introduced as a means of achieving high throughput in an X-ray astronomical imaging system in applications for which high angular resolution was not necessary. Since their introduction, their high filling factor, modest mass, relative ease of construction, and modest cost have led to their use in numerous X-ray observatories, including the Broad Band X-ray Telescope, ASCA, and Suzaku. The introduction of key innovations, including epoxy replicated surfaces, multilayer coatings, and glass mirror substrates, has led to performance improvements and in their becoming widely used for X-ray astronomical imaging at energies above 10 keV. The use of glass substrates has also led to substantial improvement in angular resolution and thus their incorporation into the NASA concept for the International X-ray Observatory with a planned 3 m diameter aperture. This paper traces the development of foil mirrors from their inception in the 1970s through their current and anticipated future applications.
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Journal Article
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 16
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[en] This paper provides a comprehensive overview on the utilization of curved graded multilayer coatings as focusing elements for hard X-rays. It concentrates on the Kirkpatrick-Baez (KB) focusing setup that has been developed at 3rd generation synchrotron sources worldwide. The optical performance of these devices is evaluated applying analytical and numerical approaches. The essential role of the multilayer coating and its meridional d-spacing gradient are discussed as well as important technological issues. Experimental data and examples of operational KB focusing devices and applications complement the work
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Numerical Data
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 8
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[en] A summary of focusing X ray poly capillary optics is presented including history, theory, modeling, and applications development. The focusing effects of poly capillary optics come from the overlap of the beams from thousands of small hollow glass tubes. Modeling efforts accurately describe optics performance to allow for system development in a wide variety of geometries. The focusing of X ray beams with poly capillary optics yields high gains in intensity and increased spatial resolution for a variety of clinical, lab-based, synchrotron or in situ analysis applications.
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X-Ray Optics and Instrumentation (Online); ISSN 1687-7640; ; v. 2010(2010); p. 17
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