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Andrea Prodi - One of the best experts on this subject based on the ideXlab platform.

  • the instrumental resolution function of synchrotron radiation powder Diffractometers in the presence of focusing optics
    Journal of Applied Crystallography, 2006
    Co-Authors: Fabia Gozzo, Liberato De Caro, Cinzia Giannini, Antonietta Guagliardi, B Schmitt, Andrea Prodi
    Abstract:

    The theory developed by Caglioti and co-workers [Caglioti, Paoletti & Ricci (1958). Nucl. Instrum. 3, 223–228; Caglioti, Paoletti & Ricci (1960). Nucl. Instrum. Methods, 9, 195–198; Caglioti & Ricci (1962). Nucl. Instrum. Methods, 15, 155–163] and Sabine [(1987). J. Appl. Cryst. 20, 23–27, 173–178] that provides an analytical description of the instrumental resolution function of single-crystal and powder Diffractometers consisting of sequences of collimators and crystals is extended by including the effect of collimating and refocusing mirrors. A simple analytical expression with only two fitting parameters (the beam divergence after reflection by the collimating and the refocusing mirrors) is determined, this expression being applicable to all mirror settings. The new theory is applied to experimental data collected at the Swiss Light Source Materials Science beamline powder diffractometer for three photon energies under extreme mirror bending conditions using the small-linewidth powder sample Na2Ca3Al2F14.

P Ramasamy - One of the best experts on this subject based on the ideXlab platform.

  • a simple and low cost solution for the automation of x ray powder Diffractometers with chart recorder output
    Journal of Applied Crystallography, 2006
    Co-Authors: M Jayaprakasan, V Kannan, P Ramasamy
    Abstract:

    X-ray powder diffraction is an established method for the qualitative identification of crystalline materials and their quantitative analysis. The new generation of X-ray diffraction systems are based on expensive digital/embedded control technology and computer interfaces. Yet many laboratories use conventional manual-controlled systems with XY strip-chart recorders. Since the output spectrum is a strip chart (hard copy), raw data, essential for structural and qualitative analysis, are not readily available for further analysis. Upgrading to modern computerized Diffractometers is very expensive. The proposed automation design described here is intended to enable the conventional diffractometer user to collect, store and analyze data quickly. The design also improves the resolution by five times compared with the conventional setup. For the automation, a PC add-on card has been designed to control and collect the timing and intensity counts from the conventional X-ray diffractometer, and suitable software has been developed to collect, process and present the X-ray diffraction data for both qualitative and quantitative analysis. Moreover, a major advantage of this design is that it does not warrant any physical modification of the hardware of the conventional setup; it is simply an extension to enhance the performance of collecting raw data with a higher resolution at desired intervals/timings.

Claude Lecomte - One of the best experts on this subject based on the ideXlab platform.

  • a mini goniometer for x ray diffraction studies down to 4 k on four circle Diffractometers equipped with two dimensional detectors
    Journal of Applied Crystallography, 2007
    Co-Authors: Pierre Fertey, Roger Argoud, Pierre Bordet, Jacques Reymann, Cyril Palin, Christophe Bouchard, Rémy Bruyère, Emmanuel Wenger, Claude Lecomte
    Abstract:

    A `universal' low-temperature device for laboratory X-ray Diffractometers equipped with two-dimensional detectors has been developed. Single-crystal data collections can be performed down to 4 K. Owing to its original design, the completeness of the data set is not affected by the limited number of accessible orientations of the sample. Classical structure analysis can therefore be performed as well as high-resolution (high-angle) studies for electron-density analysis. Derived from an idea of Argoud & Muller [J. Appl. Cryst. (1989), 22, 584–591], the sample is mounted on a holder magnetically coupled to the diffractometer φ axis. The coupling is achieved by mounting a master magnet in place of the usual goniometer head. This magnet drives a slave magnet fixed on the crystal holder: a two-axis mini-goniometer. This low-temperature arrangement is adaptable to any kappa-geometry single-crystal diffractometer equipped with a two-dimensional detector, and can be placed into various types of cryostat. This paper reports the home-made mechanical design and the performance of this device.

  • A minigoniometer for x-ray diffraction studies down to 4K on 4-circle Diffractometers equipped with 2D detectors
    Journal of Applied Crystallography, 2007
    Co-Authors: Pierre Fertey, Roger Argoud, Pierre Bordet, Jacques Reymann, Cyril Palin, Christophe Bouchard, Rémy Bruyère, Emmanuel Wenger, Claude Lecomte
    Abstract:

    A 'universal' low temperature device for laboratory x-ray Diffractometers equipped with 2D detectors has been developed. Single crystal data collections can be performed down to 4K. Due to an original design, the completeness of the data set is not affected by the limited number of accessible orientations of the sample. Classical structure analysis can therefore be performed as well as high resolution (high angle) studies for electron densities analysis. Derived from an idea of Argoud et al., the sample is mounted on a holder magnetically coupled to the diffractometer phi-axis. The coupling is achieved by mounting a master magnet in place of the usual goniometer head. This magnet drives a slave magnet fixed on the crystal holder: a two axis minigoniometer. This low temperature arrangement is adaptable to any kappa geometry single crystal diffractometer equipped with a 2D detector and can be placed into various types of cryostat. This paper reports the home made mechanical design and the performances of this device.

Fabia Gozzo - One of the best experts on this subject based on the ideXlab platform.

  • the instrumental resolution function of synchrotron radiation powder Diffractometers in the presence of focusing optics
    Journal of Applied Crystallography, 2006
    Co-Authors: Fabia Gozzo, Liberato De Caro, Cinzia Giannini, Antonietta Guagliardi, B Schmitt, Andrea Prodi
    Abstract:

    The theory developed by Caglioti and co-workers [Caglioti, Paoletti & Ricci (1958). Nucl. Instrum. 3, 223–228; Caglioti, Paoletti & Ricci (1960). Nucl. Instrum. Methods, 9, 195–198; Caglioti & Ricci (1962). Nucl. Instrum. Methods, 15, 155–163] and Sabine [(1987). J. Appl. Cryst. 20, 23–27, 173–178] that provides an analytical description of the instrumental resolution function of single-crystal and powder Diffractometers consisting of sequences of collimators and crystals is extended by including the effect of collimating and refocusing mirrors. A simple analytical expression with only two fitting parameters (the beam divergence after reflection by the collimating and the refocusing mirrors) is determined, this expression being applicable to all mirror settings. The new theory is applied to experimental data collected at the Swiss Light Source Materials Science beamline powder diffractometer for three photon energies under extreme mirror bending conditions using the small-linewidth powder sample Na2Ca3Al2F14.

Pappas C. - One of the best experts on this subject based on the ideXlab platform.

  • Design and performance of a novel neutron powder diffractometer: PEARL at TU Delft
    2016
    Co-Authors: Van Eijck L., Cussen L. D., Sykora G. J., Schooneveld E. M., Rhodes N. J., Van Well A.a., Pappas C.
    Abstract:

    The performance of the new neutron powder diffraction instrument PEARL that is installed at the research reactor of Delft University of Technology is reported. It is based on the optimization concepts developed by Cussen [Nucl. Instrum. Methods Phys. Res. Sect. A (2007), 583, 394-406], which lead to high performance competing with existing constant-wavelength neutron powder Diffractometers, despite the relatively low source brightness of the 2MW reactor of Delft University of Technology.This manuscript describes the novel neutron powder diffractometer PEARL at Delft University of Technology and shows the first experimental results.

  • Design and performance of a novel neutron powder diffractometer: PEARL at TU Delft
    'International Union of Crystallography (IUCr)', 2016
    Co-Authors: Van Eijck L., Cussen L. D., Sykora G. J., Schooneveld E. M., Rhodes N. J., Van Well A.a., Pappas C.
    Abstract:

    The performance of the new neutron powder diffraction instrument PEARL that is installed at the research reactor of Delft University of Technology is reported. It is based on the optimization concepts developed by Cussen [Nucl. Instrum. Methods Phys. Res. Sect. A (2007), 583, 394-406], which lead to high performance competing with existing constant-wavelength neutron powder Diffractometers, despite the relatively low source brightness of the 2MW reactor of Delft University of Technology.This manuscript describes the novel neutron powder diffractometer PEARL at Delft University of Technology and shows the first experimental results.RST/Neutron and Positron Methods in Material