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J Hrdý - One of the best experts on this subject based on the ideXlab platform.

  • Self-filtering extremely inclined X-ray Crystal Monochromator
    Journal of Applied Crystallography, 2011
    Co-Authors: Jaromíra Hrdá, J Hrdý
    Abstract:

    It is shown that an extremely inclined X-ray double-Crystal Monochromator can diffract a beam with the required wavelength and at the same time may reflect a great deal of unwanted radiation in a broad range of Bragg angles. This is a generalization of the idea of Cowan & Brennan [Rev. Sci. Instrum. (1989), 60, 1987–1990], which partially solves the radiation heat load problem. The properties of such a device are discussed. It is shown that in some cases the diffracted beam may be significantly broadened as a result of refraction effects. In these cases a four-Crystal arrangement or an additional mirror is necessary.

  • Harmonic-free channel-cut x-ray Crystal Monochromator with focusing effect
    Czechoslovak Journal of Physics, 2006
    Co-Authors: Jaromíra Hrdá, J Hrdý
    Abstract:

    It is shown that a channel-cut Crystal Monochromator may be harmonics-free in the whole range of Bragg angles, if the second wall is suitably curved (not bent). The curvature is described by the functionf(x)=Cx K, whereC is an arbitrary constant. There are two solutions:K 0 with the surface concave. The concave surface decreases the divergence of the diffracted beam or even it may create slightly convergent beam due to refraction. Both solutions are theoretically compared and it is shown that the concave Monochromator may be useful for sufficiently large Monochromator-sample distances.

  • Finite-element study of a toothed-Crystal Monochromator.
    Journal of synchrotron radiation, 1998
    Co-Authors: J Hrdý, J Plesek
    Abstract:

    A toothed-Crystal Monochromator, proposed in previous papers, is a modification of an inclined Monochromator, which reduces the impinging radiation power density on the surface of a Crystal for broad synchrotron radiation beams. The surface of the Monochromator has a triangular toothed structure oriented in such a way that it represents an inclined Monochromator. Finite-element analysis of thermally induced deformation was performed for a particular shape of toothed Crystal and for a flat Crystal of the same average thickness. It was estimated that the toothed-Crystal Monochromator may provide 70% higher radiation power than the flat-Crystal Monochromator.

  • Rotated-inclined double-Crystal Monochromator for synchrotron radiation: aberration and its compensation.
    Journal of synchrotron radiation, 1998
    Co-Authors: J Hrdý, E Busetto
    Abstract:

    A rotated-inclined double-Crystal X-ray Monochromator was designed for high-power undulator beamlines for SPring-8 to reduce the impinging radiation power density. Recently, it has been shown that an inclined double-Crystal Monochromator suffers from a certain type of geometrical aberration that may be relatively easily compensated. In this paper, it is shown that a similar aberration exists also in the case of rotated-inclined Monochromators and that as in the inclined case the aberration may also be compensated.

  • Observation of horizontal focusing of X-rays using a toothed-Crystal Monochromator.
    Journal of Synchrotron Radiation, 1998
    Co-Authors: J Hrdý, Sakura Pascarelli, Francesco D'acapito, S Colonna, Settimio Mobilio
    Abstract:

    The behaviour of a toothed-Crystal Monochromator for synchrotron radiation was studied for the first time on the GILDA CRG beamline at the ESRF. A new kind of horizontal focusing was observed which may be attributed to the properties of inclined diffraction. We have also observed a vertical focusing of the beam, the nature of which remains unexplained.

Sei Fukushima - One of the best experts on this subject based on the ideXlab platform.

  • Non-existence of positive glitches in spectra using the YB66 double-Crystal Monochromator of BL15XU at SPring-8
    Journal of Synchrotron Radiation, 2003
    Co-Authors: Masaru Kitamura, Hideki Yoshikawa, T. Tanaka, Tetsuro Mochizuki, A. M. Vlaicu, Atsushi Nisawa, Nobuhiro Yagi, Masato Okui, Masahiro Kimura, Sei Fukushima
    Abstract:

    YB(66) is suitable for dispersing synchrotron radiation in the 1-2 keV energy range with a 2d lattice spacing of 1.17 nm. When used with an undulator there are no positive glitches at 1385.6 and 1438 eV in spectra dispersed by a YB(66) 400 double-Crystal Monochromator as observed using bending-magnet or wiggler beamlines. The transmission function of a YB(66) double-Crystal Monochromator has been measured by means of a Si PIN photodetector, and X-ray absorption near-edge structure (XANES) of Mg, Al and Si were measured at high resolution. From all of these experiments it has been clarified that a YB(66) double-Crystal Monochromator is well suited for soft X-ray beamlines on third-generation light sources.

  • Non-existence of positive glitches in spectra using the YB(66) double-Crystal Monochromator of BL15XU at Spring-8.
    Journal of synchrotron radiation, 2003
    Co-Authors: Masaru Kitamura, Hideki Yoshikawa, T. Tanaka, Tetsuro Mochizuki, A. M. Vlaicu, Atsushi Nisawa, Nobuhiro Yagi, Masato Okui, Masahiro Kimura, Sei Fukushima
    Abstract:

    YB(66) is suitable for dispersing synchrotron radiation in the 1-2 keV energy range with a 2d lattice spacing of 1.17 nm. When used with an undulator there are no positive glitches at 1385.6 and 1438 eV in spectra dispersed by a YB(66) 400 double-Crystal Monochromator as observed using bending-magnet or wiggler beamlines. The transmission function of a YB(66) double-Crystal Monochromator has been measured by means of a Si PIN photodetector, and X-ray absorption near-edge structure (XANES) of Mg, Al and Si were measured at high resolution. From all of these experiments it has been clarified that a YB(66) double-Crystal Monochromator is well suited for soft X-ray beamlines on third-generation light sources.

  • spatial harmonic rejection in a large offset rotated inclined double Crystal Monochromator at bl15xu in spring 8
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2003
    Co-Authors: Atsushi Nisawa, Hideki Yoshikawa, Nobuhiro Yagi, Masato Okui, Takeshi Mizutani, Sei Fukushima
    Abstract:

    A 100mm offset rotated-inclined double Crystal Monochromator has been installed at BL15XU in SPring-8. The spatial profiles of the exit X-ray beam by using Si(1 1 1) in inclined geometry was measured from 5 to 20keV. The vertical deviation, due to refraction, between the first and the higher order was more than 0.7mm. The large deviation enables to eliminate the higher-order reflections by spatial screening with horizontal blade slits. The intensity ratio of the higher-order reflection to the first order was less than 10−5 over the whole energy range.

  • performance of yb66 double Crystal Monochromator for dispersing synchrotron radiation at spring 8
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2003
    Co-Authors: Masaru Kitamura, Hideki Yoshikawa, Tetsuro Mochizuki, Atsushi Nisawa, Nobuhiro Yagi, Masato Okui, Masahiro Kimura, A M Vlaicu, T Tanaka, Sei Fukushima
    Abstract:

    Abstract In the 1–2 keV range, we adopted YB 66 Crystal for dispersing synchrotron radiation of the beamline No.15 (BL15XU) at SPring-8. YB 66 Crystal has a large d -value of 0.586 nm for the 4 0 0 reflection and is useful as a soft X-ray Monochromator for dispersing synchrotron radiation, since there is no intrinsic absorption edge and it is more resistant than other Crystals to synchrotron radiation damage. We investigated the resolution of the YB 66 double-Crystal Monochromator and measured the photon flux passing through this Monochromator. The full-width at half-maximum of the rocking curve ranged from 0.15 eV at 1.1 keV to 0.42 eV at 2.1 keV. The photon flux ranged from 6×10 8  photons/sec/100 mA measured at an experimental position at 1.1 keV to 5×10 9  photons/sec/100 mA measured at an experimental position at 2 keV. It is considered that the better energy resolution of the YB 66 Crystal was achieved by irradiating only a small restricted area of the Crystal by an incident beam with small angular divergence originated from a helical undulator.

Quan Cai - One of the best experts on this subject based on the ideXlab platform.

  • A novel method for measuring the focal point of a sagittal-focusing Laue Crystal Monochromator.
    Journal of synchrotron radiation, 2019
    Co-Authors: Jiaowang Yang, Weifan Sheng, Xu Liu, Quan Cai
    Abstract:

    In order to overcome space limitations, a novel method is introduced to measure the focal point size of a sagittally bent Laue Crystal Monochromator by using a multi-hole array. Combined with ray-tracing measurements, the focal length and focused beam size were determined. Theoretical simulations and experiments were performed to demonstrate the feasibility of this method. The experimental results show that this method can provide a fast way of measuring the focusing characteristics of a sagittally bent Laue Crystal Monochromator.

  • A novel method for measuring the focal point of a sagittal-focusing Laue Crystal Monochromator.
    Journal of Synchrotron Radiation, 2019
    Co-Authors: Jiaowang Yang, Weifan Sheng, Xu Liu, Quan Cai
    Abstract:

    In order to overcome space limitations, a novel method is introduced to measure the focal point size of a sagittally bent Laue Crystal Monochromator by using a multi-hole array. Combined with ray-tracing measurements, the focal length and focused beam size were determined. Theoretical simulations and experiments were performed to demonstrate the feasibility of this method. The experimental results show that this method can provide a fast way of measuring the focusing characteristics of a sagittally bent Laue Crystal Monochromator.

E Busetto - One of the best experts on this subject based on the ideXlab platform.

Jiaowang Yang - One of the best experts on this subject based on the ideXlab platform.

  • A novel method for measuring the focal point of a sagittal-focusing Laue Crystal Monochromator.
    Journal of synchrotron radiation, 2019
    Co-Authors: Jiaowang Yang, Weifan Sheng, Xu Liu, Quan Cai
    Abstract:

    In order to overcome space limitations, a novel method is introduced to measure the focal point size of a sagittally bent Laue Crystal Monochromator by using a multi-hole array. Combined with ray-tracing measurements, the focal length and focused beam size were determined. Theoretical simulations and experiments were performed to demonstrate the feasibility of this method. The experimental results show that this method can provide a fast way of measuring the focusing characteristics of a sagittally bent Laue Crystal Monochromator.

  • A novel method for measuring the focal point of a sagittal-focusing Laue Crystal Monochromator.
    Journal of Synchrotron Radiation, 2019
    Co-Authors: Jiaowang Yang, Weifan Sheng, Xu Liu, Quan Cai
    Abstract:

    In order to overcome space limitations, a novel method is introduced to measure the focal point size of a sagittally bent Laue Crystal Monochromator by using a multi-hole array. Combined with ray-tracing measurements, the focal length and focused beam size were determined. Theoretical simulations and experiments were performed to demonstrate the feasibility of this method. The experimental results show that this method can provide a fast way of measuring the focusing characteristics of a sagittally bent Laue Crystal Monochromator.