Monte carlo simulations of the TOSCA spectrometer: Assessment of current performance and future upgrades

Pinna, Roberto S.; Rudić, Svemir; Parker, Stewart F.; Gorini, G.; Fernandez-Alonso, Félix

doi:10.1051/epjconf/20158303013

Cited by 19 publications

(15 citation statements)

References 8 publications

(7 reference statements)

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“…33 Computational details: The McStas software package [8] was used in order to perform Monte Carlo simulations of the neutron scattering at the TOSCA beamline. The geometrical parameters of the instrument primary beamline [4] were implemented in the virtual instrument, while the water moderator file [9] was provided by the ISIS Neutronics Group and was built using MCNP-X calculations of the actual TS1 target-reflector-moderator assembly. The angle between the TOSCA beamline axis and the moderator face was kept at 90º i.e.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore here we present the time-of-flight (TOF) measurements performed at different points along the TOSCA sample position surface. These results are of utmost importance in defining the current instrument baseline and for the assessment of the performance gain that will be achieved after the installation of the neutron guide along the TOSCA beamline [3,4,5].…”

Section: Introductionmentioning

confidence: 99%

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Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

Pinna

Rudić

Capstick

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

Pinna

Rudić

Capstick

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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“…Such capabilities have already been used extensively on the IRIS spectrometer [197] to study H 2 uptake in the same GIC [193]. Other neutron spectrometers where a similar experimental approach is also available include OSIRIS [198][199][200] and TOSCA [201,202], also located at the ISIS Facility.…”

Section: Molecular Hydrogen In Carbon-based Nanostructuresmentioning

confidence: 99%

Electron-volt neutron spectroscopy: beyond fundamental systems

Andreani

Krzystyniak

Romanelli

et al. 2017

Advances in Physics

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141

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This work provides an up-to-date account of the use of electron-volt neutron spectroscopy in materials research. This is a growing area of neutron science, capitalising upon the unique insights provided by epithermal neutrons on the behaviour and properties of an increasing number of complex materials. As such, the present work builds upon the aims and scope of a previous contribution to this journal back in 2005, whose primary focus was on a detailed description of the theoretical foundations of the technique and their application to fundamental systems [see Andreani et al., Adv. Phys. 54 (2005) p.377] A lot has happened since then, and this review intends to capture such progress in the field. With both expert and novice in mind, we start by presenting the general principles underpinning the technique and discuss recent conceptual and methodological developments. We emphasise the increasing use of the technique as a non-invasive spectroscopic probe with intrinsic mass selectivity, as well as the concurrent use of neutron diffraction and first-principles computational materials modelling to guide and interpret experiments. To illustrate the state of the art, we discuss in detail a number of recent exemplars, chosen to highlight the use of electron-volt neutron spectroscopy across physics, chemistry, biology, and materials science. These include: hydrides and proton conductors for energy applications; protons, deuterons, and oxygen atoms in bulk water; aqueous protons confined in nanoporous silicas, carbon nanotubes, and graphene-related materials; hydrated water in proteins and DNA; and the uptake of molecular hydrogen by soft nanostructured media, promising materials for energy-storage applications. For the primary benefit of the novice, this last case study is presented in a pedagogical and question-driven fashion, in the hope that it will stimulate further work into uncharted territory by newcomers to the field. All along, we emphasise the increasing (and much-needed) synergy between experiments using electron-volt neutrons and contemporary condensed matter theory and materials modelling to compute and ultimately understand neutron-scattering observables, as well as their relation to materials properties not amenable to scrutiny using other experimental probes

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“…A good practice has been established during the TOSCA upgrade: combining preliminary simulations [11] with detailed characterization [12]. Similar plans are being implemented both for VESPA design and TOSCA secondary spectrometer upgrade, characterizing the neutronic response of the different materials and components that will be used in the final instruments, and validating the models used to design them.…”

Section: Discussionmentioning

confidence: 99%

“…The upgrade was guided by a combination of simulation (performed with the McStas package [10]) and experimental characterization of the instrument, which also allows us to quantify the neutronic response before and after the upgrade. A number of preliminary simulations set the achievable gain from the guide installation, then allowing a refined design [11] which ended in the currently installed tapered guide, characterized by m-values that, moving towards sample position, increase from 5 to 7 [9]. The simulations were supported by a careful characterization of the beam [12], then repeated after the upgrade [9] which allows us to identify an average gain of more than a factor ten over the most useful range of the spectrum, with a maximum of two orders of magnitude in flux at the lowest incident energies, and no detriment to resolution or signal-to-noise ratio.…”

Section: Toscamentioning

confidence: 99%

Neutronic developments on TOSCA and VESPA: Progress to date

Zanetti

Bellissima

Rosso

et al. 2019

Physica B: Condensed Matter

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A B S T R A C TWe report recent developments regarding the TOSCA (ISIS, UK) and VESPA (ESS, Sweden) neutron broadband chemical spectrometers, both joint ventures between CNR (IT) and ISIS (UK). TOSCA has seen the first major upgrade since it first became operational over fifteen years ago. The new design of the primary spectrometer, which exploits a state-of-the-art, high-m neutron guide and associated chopper system, is boosting the useful neutron flux by over an order of magnitude. Feasibility studies for an upgrade of the secondary spectrometer have been performed, outlining an additional order-of-magnitude gain in performance. In the case of VESPA, the novel characteristics and challenges arising from a long-pulse spallation source such as ESS are part of the drivers of the instrument design. For both the primary and secondary spectrometers, a detailed analysis of expected performance, supported by both simulations and analytical models, is being carried out, also capitalizing from experience on TOSCA. Indeed, for instrument design and optimization, extensive neutron-transport simulations and baseline studies of neutronic response have become a must, along with extensive benchmarking against much-needed experimental data. All these combined efforts represent the first opportunity to benchmark a broadband, high-resolution chemical spectrometer in terms of measured vs. simulated response. High-resolution broadband chemical spectrometersInelastic Neutron Scattering (INS) as a vibrational spectroscopy technique [1] is widely used across chemistry, materials science, biology, and beyond. The workhorses for this kind of studies can be called "High-resolution Broadband Chemical Spectrometers". Here, we focus on time-of-flight instruments at pulsed spallation sources in socalled indirect geometry, and whereby final-energy selection is attained with a crystal after scattering by the sample. With them, good-quality spectra (i.e. high count rate and resolution) can be obtained with reasonably small quantities of specimen and easy operation. This type of instruments is generally divided into a Primary Spectrometer (PS), dedicated to neutron delivery from a moderator to the sample, and a Secondary Spectrometer (SS) which processes neutrons scattered from the sample and delivers them to the detectors.In the PS the polychromatic beam, coming from the moderator, is generally worked on by a chopper system (i.e. shaping or cleaning it) and transported onto the sample by a neutron delivery device (e.g. an evacuated tube or a super-mirror guide). The SS is arranged in such a way that the final energy of neutrons that can be detected after scattering by the sample is fixed. This is achieved via the use of an analyser crystal, typically HOPG (Highly Oriented Pyrolytic Graphite), which selects the neutrons through Bragg scattering. In order to eliminate higher-order crystal reflections, a low-pass energy filter is used. The filter is typically made with a thick block of beryllium, selecting the bandwidth by exploiting the Bragg cut...

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Monte carlo simulations of the TOSCA spectrometer: Assessment of current performance and future upgrades

Cited by 19 publications

References 8 publications

Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

Electron-volt neutron spectroscopy: beyond fundamental systems

Neutronic developments on TOSCA and VESPA: Progress to date

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