Browsing by Author "Pangelis, S"

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    Neutron optics upgrades to the residual stress diffractometer, KOWARI
    (Materials Research Forum LLC, 2016-07-03) Reid, M; Olsen, SR; Luzin, V; New, M; Booth, N; Clowes, D; Nguyen, T; Franceschini, F; Ogrin, A; Pangelis, S; Paradowska, AM; Larkin, N; Pan, Z; Hoye, N; Suzuki, H
    In the last 5 years a number of significant enhancements have been implemented on the neutron beam strain scanner Kowari at the OPAL reactor in Sydney Australia. These changes have resulted in reduced beam time losses when conducting experiments due to sample and stage alignment, and optics and sample changes. There have been 3 projects, starting in 2011 with a new manual slit system design and collision recovery system, in 2013 with a series of radial collimators and finally with the delivery. © The Authors
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    Recent enhancements and performance gains from upgrades to ANSTO's thermal neutron instrument TAIPAN and the triple-axis and Be-filter spectrometers
    (Australian Nuclear Science and Technology Organisation, 2017-11-28) Rule, KC; Ogrin, A; Berry, A; Stampfl, APJ; Bartlett, D; Franceschini, F; Darmann, FA; Olsen, SR; Danilkin, SA; Pangelis, S; Oste, T; Ersez, T
    TAIPAN is the thermal-neutron spectrometer located at the reactor face of Australia's OPAL reactor (ANSTO). TAIPAN hosts two interchangeable secondary instruments; the triple-axis spectrometer (TAS) and the beryllium filter spectrometer. The TAS option has been operating since 2010 whilst the Be-filter only began operating in 2015. TAIPAN is renowned for its versatility and high neutron flux which has allowed the TAS to measure a broad range of samples including single crystals, powders, thin films, and co-aligned multi-crystal arrays. While the TAS option is used mostly to study structural and magnetic excitations in materials, the Be-filter option is used to measure vibrational density of states from powder samples. TAIPAN has recently undergone some upgrades to improve the accessible momentum and energy range of both the TAS and the Be-filter spectrometers. Four key features have been modified to improve performance: the accessible momentum transfer has been increased by re-designing the enclosure; a sapphire-filter translation-stage mechanism has been installed to allow epithermal neutrons to pass to the monochromators; a new Cu-200 double-focussing monochromator has been installed to allow monochromatic scattering of neutrons up to 180 meV; and finally a new tertiary shutter and snout have been designed to improve the signal-to-noise ratio and reduced background outside the instrument enclosure. Extensive testing and alignment of all new motion stages were undertaken with reproducibility within ±0.05degrees or ±0.25mm obtained for both the monochromator rotation angle & sapphire-filter alignment. © The Authors.
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    Recent upgrades to ANSTO’s thermal neutron spectrometer, TAIPAN
    (Australian Institute of Physics, 2018-01-30) Rule, KC; Darmann, FA; Oste, T; Olsen, SR; Bartlett, D; Franceschini, F; Berry, A; McGregor, A; Ogrin, A; Ersez, T; Kafes, A; Pangelis, S; Danilkin, SA; Stampfl, APJ
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    Report on the repair of the OPAL neutron beam transport system
    (International Group On Research Reactors, 2013-10-13) Pullen, SA; Davidson, G; Pangelis, S; Klose, F; Kennedy, SJ
    The OPAL research reactor commenced operation early in 2007, and has been in continuous operation for most of the time since then. Initial characterization measurements of the cold and thermal neutron beams that feed the neutron guide hall confirmed the high fluxes that had been predicted in the design process [1], [2]. However, by 2011 it was clear that the performance of the neutron guide system had degraded substantially. Investigation revealed that the degradation resulted from delamination of the guides. The root cause was build-up of mechanical stress in the glass substrates due to alpha radiation produced during neutron capture by boron in the glass. Remediation involved replacement of 72 metres of the neutron guide system with guides that use glass substrates which have higher radiation resistance. Neutron flux and spectrum measurements have since verified that the performance of the system has largely been restored. Preliminary measurements at the neutron spectrometers since repair reveal flux increases in the range of 40 % to 90 % relative to 2011. © The Authors
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    Safety interlock and vent system to alleviate potentially dangerous ice blockage of top-loading cryostat sample sticks
    (Wiley-Blackwell, 2013-08-01) Pangelis, S; Olsen, SR; Scherschligt, J; Leao, JB; Pullen, SA; Dender, D; Hester, JR; Imperia, P
    A combined solution is presented for minimizing the safety hazards associated with closed cycle cryostats described by Swainson & Cranswick [J. Appl. Cryst. (2010), 43, 206-210]. The initial solution is to install a vent tube with one open end deep inside the sample space and a pressure relief valve at the top. This solution works for either a cryogen or a cryogen-free (closed cycle) system. The second approach, which can be combined with the first and is applicable to cryogen-free cryostats, involves electrically interlocking the closed cycle refrigerator compressor to the sample space, so that the system cannot be cooled in the presence of a leak path to air. © 2013, Wiley-Blackwell.