Browsing by Author "Lal, J"

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    The performance of magnetic lens for focusing VCN-SANS
    (Elsevier, 2011-04-01) Yamada, M; Iwashita, Y; Kanaya, T; Ichikawa, M; Tongu, H; Kennedy, SJ; Shimizu, HM; Mishima, K; Yamada, NL; Hirota, K; Carpenter, JM; Lal, J; Andersen, KH; Geltenbort, P; Guerard, B; Manzin, G; Hino, M; Kitaguchi, M; Bleuel, M
    We have developed a prototype rotating-permanent magnet sextupole lens (named rot-PMSx) for more efficient experiments with neutron beams in time of flight (ToF) mode. This lens can modulate the focusing strength over range 1.5 x 10(4)T/m(2) <= g' <= 5.9 x 10(4) T/m(2). Synchronization between the modulation and the beam pulse produces a focused beam without significant chromatic aberration. We anticipate that this lens could be utilized in focusing small angle neutron scattering (SANS) instruments for novel approach to high resolution SANS. We carried out experiments testing the principle of this lens at the very cold neutron (VCN) beamline (PF2) at Institut Laue-Langevin (ILL), France. The focused beam image size at the detector was kept constant at the same beam size as the source (approximate to 3 mm) over a wavelength range of 30 angstrom <= lambda <= 48 angstrom in focal length of approximate to 1.14m. The flux gain was about 12 relative to a beam without focusing, and the depth of focus was quite large. These results show the good performance of this lens and the system. Thereupon we have demonstrated the performance of this test bed for high resolution focusing of VCN-SANS for a well-studied softmatter sample; a deuterium oxide solution of Pluronic F127, an (PEO)(100)(PPO)(65)(PEO)(100) tri-block copolymer in deuterium oxide. The results of the focusing experiment and the focusing VCN-SANS are presented. (C) 2010 Elsevier B.V. All rights reserved.
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    Phase separation in the organic solid state: simultaneous synchrotron SAXS / DSC studies of unstable n-alkane blends
    (Australian Institute of Physics, 2005-01-31) Gilbert, EP; Nelson, A; Sutton, D; Terrill, N; Martin, C; Lal, J; Lang, EA
    Blends of normal alkanes form lamellar structures, when quenched from the melt, in which the separation of the individual chains may be controlled by the chain-length difference, molar composition, isotopic substitution and confinement. We have performed simultaneous synchrotron small-angle X-ray scattering and differential scanning calorimetry studies on 2:1 C28H58:C36D74 mixtures as a function of cooling protocol. Their simultaneous collection enables the temperature-dependent nanostructural changes to be correlated with phase transitions. The data are further complemented by small-angle neutron scattering highlighting the separation of the individual chains via isotopic contrast and optical microscopy indicating changes occurring on the macroscopic scale.
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    A small angle neutron scattering (SANS) experiment using very cold neutrons (VCN)
    (Elsevier, 2009-09-01) Bleuel, M; Carpenter, JM; Micklich, BJ; Geltenbort, P; Mishima, K; Shimizu, HM; Iwashita, Y; Hirota, K; Hino, M; Kennedy, SJ; Lal, J
    This paper describes the results of SANS measurements of small samples using the very cold neutron (VCN) beam of the PF2 instrument at the Institut Laue Langevin (ILL), France. In addition to a classical SANS pinhole collimation, the experiment used a polarizing supermirror as a monochromator and a magnetic sextupole lens to focus the neutron beam in order to gain intensity and avoid any material in the neutron beam besides the sample. © 2009, Elsevier Ltd.