Browsing by Author "Davidson, G"
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- ItemACNS sample environment update(Australian Nuclear Science and Technology Organisation, 2021-11-25) White, R; Davidson, G; D'Adam, TM; Booth, N; Baldwin, C; Shumack, ASince the last ANSTO User Meeting the sample environment group at ACNS has supported our facility users with a range of unique developments and set ups. We have had a change in structure with the laboratory group forming and working alongside us. We will report on the progress on our ongoing projects on Direct Laser Melting (DLM) deposition system co-funded by a NSW RAAP grant. Also underway are LIEF grants with equipment for use at ACNS, one includes a rheometer for use on ACNS beam instruments. This presentation will also cover our new equipment projects funded by the NCRIS RIIP scheme. This includes new cryofurnaces, a new type of furnace, a universal testing machine and other equipment. This funding will maintain and improve our existing capabilities and increase the redundancy across the SE suite to better service competing requests. © The Authors
- ItemAustralian centre for neutron scattering: sample environment report(Australian Institute of Nuclear Science and Engineering (AINSE), 2018-11-19) Manning, AG; Wakeham, D; Davidson, G; Booth, N; Imperia, P; White, R; Lee, S; D'Adam, TMIn the past 2 years since the 2016 AANSS symposium, the sample environment group of the Australian Centre for Neutron Scattering (ACNS) has continued to facilitate neutron experiments and expand sample environment capability. This report will present the current sample environment and laboratory facilities and recent developments. We have made progress in light irradiation and spectroscopy developments; on a new temperature controlled multi-sample changer with tumbling capability; on a rotational PE Cell; and on new sample probes made from composite materials. Other improvements include new high pressure couplings for helium compressors and modifications to a dilution insert to allow larger samples and use in other cryostats extending the capability. Ongoing major projects are a new superconducting split-coil magnet dedicated to SANS and TOFPAS, two new cryostats (1.5 K to 800 K temperature range) with the aim of halving the system and sample cooling time and a new dilution fridge that will allow top-loading of samples and the ability to take much larger samples than the existing dilution insert. There have also been staffing changes with previous Sample Environment Group Leader, Paolo Imperia moving into the Operations Manager position. The new group leader, Rachel White, was recently appointed. Our Laboratory Manager, Deborah Wakeham, joined us in July 2017. © The Authors.
- ItemDevelopment of Direct Laser Melting (DLM) deposition system for in-situ use on neutron beam instruments(Australian Institute of Nuclear Science and Engineering (AINSE), 2020-11-11) Baldwin, C; White, R; Paradowska, AM; Booth, N; Davidson, G; D’Adam, TM; Shumack, A; Darmann, FDirect Laser Melting (DLM) deposition is an additive manufacturing technique in which a high power laser is used to create a melt pool on a workpiece while a jet of metal powder is applied, resulting in localised material deposition. This technique is used in industry for additive repairs, cladding with dissimilar metals, or, in conjunction with a CNC milling machine, as a full-fledged 3D additive fabrication platform. As the prominence of this technology rises, so too does interest in characterising deposition dynamics over a vast parameter space. Neutron beam instruments offer unique capabilities for such characterisation. As part of the NSW Research Attraction and Acceleration Program, ACNS is developing world first sample environment capabilities enabling in-situ laser metal deposition, for use on KOWARI and DINGO beamline. The system will utilise a self-contained motion stage and laser cladding head which will construct a thin wall structure on a user specified substrate, utilising up to two metal powders at a time. Neutron studies of the melt pool or heat affected zone can then be performed during and after printing. This paper will present the technical specifications and capabilities of the system, which will be available to the user community in late 2021. © The authors.
- ItemIntegration of polarised 3He infrastructure with sample environment equipment(Australian Institute of Physics, 2017-01-31) D'Adam, TM; Booth, N; Davidson, G; Lee, S; Manning, AG; Timperon, N; Imperia, PMany challenges exist when attempting to integrate polarised 3He infrastructure with neutron beam instruments. This is often due to its sensitivity to the magnetic environment and also due to the compact geometry of many beam lines. One additional consideration is the effect that Sample Environment equipment can have on the functionality of a particular polarised neutron setup. We have been able to provide incident beam polarisation with two separate magnets providing fields at the sample position of up to 2 T. In addition, full polarisation analysis is possible over a temperature range of 30 mK to 800 K. To enable this, some pieces of Sample Environment equipment must be designed specifically for use with polarised 3He and in many cases modifications are necessary to accommodate the sensitive gas. We are also in the process of procuring an 8 T shielded asymmetric magnet suitable for use with polarised 3He infrastructure.
- ItemNew sample environment projects and developments at the Australian Centre for Neutron Scattering(Australian Institute of Physics, 2019-02-05) White, R; Imperia, P; Booth, N; D'Adam, TM; Davidson, G; Lee, S; Manning, AG; Tobin, SSince the 2018 meeting the sample environment team at the Australian Centre for Neutron Scattering (ACNS) has progressed the design and construction of the new superconducting split-coil magnet, a fast cooling closed cycle cryostat and a new type of closed cycle dilution refrigerator. The first of the two fast cooling cryostats (compact closed cycle dry cryostats, 1.5 K to 800 K) will arrive in early 2019, with a tested sample cool down of 30 minutes. The new magnet is in the final stages of design, including a sample well for our time-of-flight spectrometer PELICAN. The new magnet will have active magnetic shielding and an asymmetric coil design to allow experiments with polarised neutrons. The expected arrival for the magnet is mid-2019. The closed cycle dilution refrigerator will have high cooling power and a very large sample space allowing a new class of experiments with neutrons at ultra-low temperature, arriving in March 2019. Also presented is the development of carbon fibre sample probes to enable faster cooling and quicker sample changes.
- ItemNew sample environment projects and developments at the Australian Centre for Neutron Scattering(International Conference on Neutron Scattering, 2017-07-12) Imperia, P; Booth, N; D'Adam, TM; Davidson, G; Lee, S; Manning, AGThe sample environment team at the Australian Centre for Neutron Scattering (ACNS) has been recently awarded funding for a new superconducting split-coil magnet, a fast closed cycle cryostat and a closed cycle dilution refrigerator of the latest generation. The new magnet design is of particular interest; the brief is complicated by the request to serve two separate classes of instruments: small angle scattering and time of flight. The magnet will have low fringe field, active shield design, and specific requirements for the asymmetric field gradient to allow experiments with polarised neutrons. Low fringe field values are combined with a minimum central field of 7 Tesla, wide “clean” scattering angle and dimensional and weight constraints. The design challenges and possible solutions will be detailed, together with a time frame for delivery and commissioning. The new compact closed cycle cryostat (1.5 K to 800 K) with a small He dump, aims to halve the system and sample cooling time, generating performances comparable to that of wet type “orange” cryostats without the necessity to refill with cryogenic liquids. The closed cycle dilution refrigerator will have high cooling power and large sample space, allowing new class of experiments with neutrons at ultra-low temperature. The most recent equipment built in-house and unique to the ACNS, such as the Peltier sample changer and the thermalised sample tumblers for SANS and USANS, will also be discussed.
- ItemNew sample environment projects and developments at the Australian Centre for Neutron Scattering.(Australian Institute of Physics, 2018-01-30) Imperia, P; Booth, N; D'Adam, TM; Davidson, G; Lee, S; Manning, AG; Tobin, S
- ItemA peltier controlled sample changer for SANS(Australian Institute of Nuclear Science and Engineering, 2016-11-29) Lee, S; Booth, N; Imperia, P; Davidson, GA twelve position sample changer for SANS instruments at ACNS has been developed and will be available for users in the near future. The design philosophy for this project was to make the system as modular and scalable as possible with an emphasis on ease of use for the user and reduced background. The Peltier control system allows each sample to be controlled at different temperatures and allows the possibility of producing very fast temperature changes over a limited range. The system can be controlled via a local Watlow™ touchscreen and remotely via the SICS based neutron instrument control system used at ACNS. The liquid cooled heatsink for the Peltiers provides the support for the spring loaded sample holders, allowing rapid sample changes. The width of the sample changer has been reduced compared to the existing 20 position and with Borated aluminium shielding the background with blocked beam has been improved. The temperature sensors used are K-type thermocouples. Performance and stability tests will be presented. A design for uSANS is being developed.
- ItemReport 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, SJThe 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
- ItemSpin dynamics and magnetoelectric coupling mechanism of Co4Nb2O9(American Physical Society, 2018-02-28) Deng, GC; Cao, YM; Ren, W; Cao, SX; Studer, AJ; Gauthier, N; Kenzelmann, M; Davidson, G; Rule, KC; Gardner, JS; Imperia, P; Ulrich, C; McIntyre, GJNeutron powder diffraction experiments reveal that Co4Nb2O9 forms a noncollinear in-plane magnetic structure with Co2+ moments lying in the ab plane. The spin-wave excitations of this magnet were measured by using inelastic neutron scattering and soundly simulated by a dynamic model involving nearest- and next-nearest-neighbor exchange interactions, in-plane anisotropy, and the Dzyaloshinskii-Moriya interaction. The in-plane magnetic structure of Co4Nb2O9 is attributed to the large in-plane anisotropy, while the noncollinearity of the spin configuration is attributed to the Dzyaloshinskii-Moriya interaction. The high magnetoelectric coupling effect of Co4Nb2O9 in fields can be explained by its special in-plane magnetic structure. ©2018 American Physical Society
- ItemThree impossible things before lunch - the task of a sample environment specialist(IOS Press, 2017-11-16) Booth, N; Davidson, G; Imperia, P; Lee, S; Stuart, BH; Thomas, PS; Komatsu, K; Yamane, R; Prescott, SW; Maynard-Casely, HE; Nelson, A; Rule, KCIn the course of their day, sample environment professionals can be confronted by numerous technical challenges applicable to a range of scientific questions. This paper presents three successful outcomes from user-posed sample environment challenges for in situ neutron scattering experiments undertaken at the Australian Centre for Neutron Scattering (formerly the Bragg Institute). The sample environments presented here have nothing in common other than their novelty. They may not be the best solution but have been constrained by time, resources and ability. The questions the users posed were: Can we mount a cylinder in cylinder (CIC) rheometer, more regularly used on a small angle scattering instrument, on a diffraction instrument and obtain usable data? Can we supply high-voltage (up to 10 kV) across a sample within the Paris–Edinburgh press while mounted on a powder diffraction instrument? And finally can a Lakeshore 340 and an in-house built liquid conductivity cell do the job of a commercial liquid conductivity meter? This paper presents the engineering and equipment solutions that were used to answer these questions, and in each case the scientific users left with useful, intriguing and, hopefully, publishable data. © 2017 IOS Press