Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

Pinna, Roberto S.; Rudić, Svemir; Capstick, Matthew J.; McPhail, D.; Pooley, Daniel E.; Howells, Gareth D.; Gorini, G.; Fernandez-Alonso, Félix

doi:10.1016/j.nima.2017.07.018

Cited by 23 publications

(25 citation statements)

References 7 publications

(5 reference statements)

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“…The experimental high-resolution vibrational neutron spectroscopy, INS, was carried out at the ISIS Pulsed Neutron and Muon source on the inverted-geometry TOSCA instrument at ≈10 K in a closed-cycle helium refrigerator [18][19][20][21]. A 5 g powder sample was measured in a flat aluminium cell with 4×4.8 cm 2 cross-section area.…”

Section: Methodsmentioning

confidence: 99%

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

et al. 2019

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Kobayashi et al (6279) (Science 2016, 351) reported recently the existence of pure Hconductivity in the oxyhydride La 2−x−y Sr x+y LiH 1−x+y O 3−y , while demonstrating its functionality through a prototype solid-state Ti/La 2 LiHO 3 /TiH 2 battery. In this study, we probe the atomistic motion of La 2 LiHO 3 obtained by the promising halide salt flux method, via a combination of deep inelastic neutron scattering (DINS) and ab initio lattice dynamics (LD) calculations verified by vibrational inelastic neutron spectroscopy (INS). We successfully describe the measured momentum distributions from DINS via our LD calculations, without observing any diffusion activation over the temperature range reported by Kobayashi et al. This observation is corroborated by model predictions from our LD study, which reveals that the hydride anions remain bound within a 3D-harmonic potential. We conclude that with the current synthesis parameters, the method produces a vacancy free lattice, and that a necessary ingredient for diffusive motion of His the presence of a large population of vacancies. Based on the harmonic prediction for the hydrogen kinetic energy, we derive a picture of the evolution of the effective bonding potential for the hydride anions, and link this to the dynamics associated with decomposition of the oxyhydride.

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Section: Methodsmentioning

confidence: 99%

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

et al. 2019

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“…Inelastic neutron scattering experiments were performed with the TOSCA spectrometer [42,43], an indirect geometry time-of-flight spectrometer at the ISIS Neutron and Muon Source at the Rutherford Appleton Laboratory (Chilton, UK) [52]. The final neutron energy was approximately 3.95 meV, and the energy resolution, ∆E/E was about 1.25% between 400 and 1600 cm −1 and increased to more than 1.5% in 2400-4000 cm −1 range.…”

Section: Neutron Scattering Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…120 and 176 cm −1 ) by combining INS with the deuteration of hydroxyl groups in the non-crystalline regions of native cellulose [38]. Further down the road, Araujo et al [39] explored the dynamics of hydrogen bonds in cellulose samples from distinct sources, namely microcrystalline cellulose, cotton cellulose, kraft pulp cellulose and BC, by INS (with the help of the TOSCA spectrometer) [40][41][42][43] and were able to easily distinguish between the crystalline forms of I α and I β allomorphs in the 700−800 cm −1 region. Moreover, this study set the stage for the future use of this technique to characterize BC-based materials, and in particular of nanocomposites [39].Under these premises and following our interest in the design and characterization of advanced and multifunctional BC-based nanocomposites [11,13,24], the present work intends to study the dynamics of hydrogen-bond networks in BC-based nanocomposites containing poly(2-hydroxyethyl methacrylate) (PHEMA), poly(methacroylcholine chloride) (PMACC) and poly(methacroylcholine hydroxide) (PMACH) by INS spectroscopy.…”

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Understanding the Structure and Dynamics of Nanocellulose-Based Composites with Neutral and Ionic Poly(methacrylate) Derivatives Using Inelastic Neutron Scattering and DFT Calculations

et al. 2020

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Bacterial nanocellulose (BC)-based composites containing poly(2-hydroxyethyl methacrylate) (PHEMA), poly(methacroylcholine chloride) (PMACC) or poly(methacroylcholine hydroxide) (PMACH) were characterized by inelastic neutron scattering (INS) spectroscopy, combined with DFT (density functional theory) calculations of model systems. A reasonable match between calculated and experimental spectral lines and their intensities was used to support the vibrational assignment of the observed bands and to validate the possible structures. The differences between the spectra of the nanocomposites and the pure precursors indicate that interactions between the components are stronger for the ionic poly(methacrylate) derivatives than for the neutral counterpart. Displaced anions interact differently with cellulose chains, due to the different ability to compete with the O-H···O hydrogen bonds in cellulose. Hence, the INS is an adequate technique to delve deeper into the structure and dynamics of nanocellulose-based composites, confirming that they are true nanocomposite materials instead of simple mixtures of totally independent domains. Keywords: bacterial nanocellulose; nanocomposites; poly(2-hydroxyethyl methacrylate); poly(methacroylcholine chloride); poly(methacroylcholine hydroxide); inelastic neutron scattering; DFT calculations IntroductionA tour through the kaleidoscopic portfolio of materials developed in the last decades, clearly shows that composite materials based on cellulose [1], and bacterial nanocellulose (BC) in particular [2], are quite relevant for myriad domains of applications [3][4][5]. In fact, the exopolysaccharide BC, which is biosynthesized by several non-pathogenic bacteria in the form of membranes with a tree-dimensional network of cellulose nanofibrils [6], has shown potential for drug delivery [7-9], wound healing [10,11], bone tissue engineering [12], antimicrobial materials [13], food and food packaging [14,15], water remediation [16,17] and fuel cells [5,18,19], just to mention some fields of application.In terms of production, BC-based nanocomposites can be prepared by in situ and ex situ methodologies [20], which already enabled the combination of BC with a vast array of synthetic polymers Molecules 2020, 25, 1689 2 of 16 (e.g., polyaniline [21] and Nafion [22]) and biopolymers (e.g., lactoferrin [23] and fucoidan [24]), as well as hybrid materials with metal oxides, metal sulphides and metal nanoparticles [4], and graphene and derivatives [25,26], with the aim of enhancing or adding novel properties to the ensuing materials [2]. Among the available methodologies, the in situ polymerization of monomers with, for instance, (metha)acrylate functional groups, is a simple top-down method that promotes the use of BC without altering its valuable and unique three-dimensional structure [2]. Acrylamide [27], acrylic acid [28], glyceryl monomethacrylate [29], 2-ethoxyethyl methacrylate [29], 2-aminoethyl methacrylate [30], methacryloyloxyethyl phosphate [31], N-methacryloyl glycine [7] and bis[2-(me...

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“…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. A similar procedure is being followed for the next possible upgrade of the SS.…”

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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Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

Cited by 23 publications

References 7 publications

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

Understanding the Structure and Dynamics of Nanocellulose-Based Composites with Neutral and Ionic Poly(methacrylate) Derivatives Using Inelastic Neutron Scattering and DFT Calculations

Neutronic developments on TOSCA and VESPA: Progress to date

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Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

Cited by 23 publications

References 7 publications

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La2LiHO3 oxyhydride

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La2LiHO3 oxyhydride

Understanding the Structure and Dynamics of Nanocellulose-Based Composites with Neutral and Ionic Poly(methacrylate) Derivatives Using Inelastic Neutron Scattering and DFT Calculations

Neutronic developments on TOSCA and VESPA: Progress to date

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A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride

A combined deep inelastic neutron scattering and ab initio lattice dynamics study of the hydride anion dynamics and bonding in La₂LiHO₃ oxyhydride