The new small-angle neutron scattering instrument SANS-1 at MLZ—characterization and first results

Mühlbauer, S.; Heinemann, A.; Wilhelm, Andreas; Karge, Lukas; Ostermann, Andreas; Defendi, I.; Schreyer, A.; Petry, W.; Gilles, Ralph

doi:10.1016/j.nima.2016.06.105

Cited by 53 publications

(35 citation statements)

References 23 publications

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“…The neutron study on the IMS formation was performed on the SANS instruments SANS-1 at MLZ and TPA at the Laboratoire Léon Brillouin, the USANS beamline BT-5 at the NIST Center for Neutron Research and the nGI setup at the ANTARES neutron radiography beamline at MLZ. The setups are described in Mühlbauer et al 28 , Désert et al 29 , Barker et al 30 and Reimann et al 31 , respectively. While SANS probes the vortex lattice and permits to obtain its symmetry and spacing, USANS probes structures on a µm scale and provides the morphology of IMS domains.…”

Section: Experimental Methodsmentioning

confidence: 99%

Domain formation in the type-II/1 superconductor niobium: Interplay of pinning, geometry, and attractive vortex-vortex interaction

et al. 2017

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Vortex attraction which can cause a bundling of vortices has been observed in a multitude of type-II superconductors. While its underlying mechanisms have been extensively studied, the morphology of the emerging vortex superstructure has only been rarely considered. Here, we present a comprehensive experimental study on the type-II/1 superconductor niobium which focuses on the transformation of its homogeneous vortex lattice into an inhomogeneous domain structure at the onset of vortex attraction. By means of small-angle neutron scattering, ultra-small-angle neutron scattering, and neutron grating interferometry, the vortex lattice, the micrometer-scale vortex domain structure as well as its distribution could be investigated. In particular, we focus on the transformation of the vortex lattice at the transition to the intermediate mixed state which is characterized by vortex attraction. We have found that the phase separation of the vortex lattice into an irregular domain structure takes place via a process showing strong similarity to spinodal decomposition. While pinning disorders the domain morphology, the characteristic length scale of the domain structure is governed by an interplay of field distortion energy and domain surface tension. Finally, geometric barriers in the disc-shaped samples provoke an inhomogeneous distribution of domains on the macroscopic scale.

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Section: Experimental Methodsmentioning

confidence: 99%

Domain formation in the type-II/1 superconductor niobium: Interplay of pinning, geometry, and attractive vortex-vortex interaction

et al. 2017

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“…It is possible to calculate the 3 He efficiency either in the thermal spectrum region or for the background, the index i in equation 5 refers to the two possibilities. The calculation of thermal efficiency serves as a proof of the reliability of this method, whereas the 3 He efficiency is widely known [49].…”

Section: Further Evidence Of Fast Neutron Sensitivity Of 3 He Detectomentioning

confidence: 99%

Fast neutron sensitivity for 3He detectors and comparison with Boron-10 based neutron detectors

et al. 2019

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The 3 He-based neutron detectors are no longer the default solution for neutron scattering applications. Both the inability of fulfilling the requirements in performance, needed for the new instruments, and the shortage of 3 He, drove a series of research programs aiming to find new technologies for neutron detection. The characteristics of the new detector technologies have been extensively tested to prove their effectiveness with respect to the state-of-the-art technology.Among these, the background rejection capability is crucial to determine. The signal-to-background ratio is strongly related to the performance figure-of-merit for most instruments. These are designed to exploit the high flux expected from the new high intensity neutron sources. Therefore, an inadequate background rejection could significantly affect the measurements, leading to detector saturation and misleading events. This is of particular importance for the kind of techniques in which the signals are rather weak.For the first time, the sensitivity of 3 He detectors to fast neutrons, up to E n = 10 MeV, has been estimated. Two independent measurements are presented: a direct calculation based on a subtraction method used to disentangle the thermal and the fast neutron contribution, while a further evidence is calculated indirectly through a comparison with the recently published data from a 10 B-based detector. Both investigations give a characterization on the order of magnitude for the sensitivity. A set of simulations is presented as well in order to support and to validate the results of the measurements. A sensitivity of 4 · 10 −3 is observed from the data. This is two orders of magnitude higher than that previously observed in 10 B-based detectors.

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“…Leibnitz Zentrum (MLZ) in Garching, Germany (Gilles et al, 2006;Mü hlbauer et al, 2016;Heinemann & Mü hlbauer, 2015). Measurements were performed with a neutron wavelength of 6 Å and a sample-to-detector distance of 8 m (the same value was chosen for the collimation) to cover a medium q range of 0.068-0.934 nm À1 [q = (4/) sin, where is half the scattering angle and is the wavelength of the incident beam].…”

Section: Methodsmentioning

confidence: 99%

Li-ion half-cells studied operando during cycling by small-angle neutron scattering

et al. 2020

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Small-angle neutron scattering (SANS) was recently applied to the in situ and operando study of the charge/discharge process in Li-ion battery full-cells based on a pouch cell design. Here, this work is continued in a half-cell with a graphite electrode cycled versus a metallic lithium counter electrode, in a study conducted on the SANS-1 instrument of the neutron source FRM II at the Heinz Maier-Leibnitz Zentrum in Garching, Germany. It is confirmed that the SANS integrated intensity signal varies as a function of graphite lithiation, and this variation can be explained by changes in the squared difference in scattering length density between graphite and the electrolyte. The scattering contrast change upon graphite lithiation/delithiation calculated from a multi-phase neutron scattering model is in good agreement with the experimentally measured values. Due to the finite coherence length, the observed SANS contrast, which mostly stems from scattering between the (lithiated) graphite and the electrolyte phase, contains local information on the mesoscopic scale, which allows the development of lithiated phases in the graphite to be followed. The shape of the SANS signal curve can be explained by a core-shell model with step-wise (de)lithiation from the surface. Here, for the first time, X-ray diffraction, SANS and theory are combined to give a full picture of graphite lithiation in a half-cell. The goal of this contribution is to confirm the correlation between the integrated SANS data obtained during operando measurements of an Li-ion half-cell and the electrochemical processes of lithiation/delithiation in micro-scaled graphite particles. For a deeper understanding of this correlation, modelling and experimental data for SANS and results from X-ray diffraction were taken into account. research papers J. Appl. Cryst. (2020). 53, 210-221 Johannes Hattendorff et al. SANS operando study of Li-ion half-cells 211 research papers 212 Johannes Hattendorff et al. SANS operando study of Li-ion half-cells J. Appl. Cryst. (2020). 53, 210-221 Figure 2An operando X-ray diffractogram recorded from the Li/graphite half-cell cycled at C/5, showing the presence of well defined lithiation stages, which indicates good homogeneity across the electrode. J. Appl. Cryst. (2020). 53, 210-221 Johannes Hattendorff et al. SANS operando study of Li-ion half-cells 219 Figure 9An illustration of the calculation mesh and the coherence volumes centred at each mesh element k, (a) for small particles and (b) for a large particle with two phases, e.g. active material and electrolyte or solvent. One square is of the order of 30 nm.

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The new small-angle neutron scattering instrument SANS-1 at MLZ—characterization and first results

Cited by 53 publications

References 23 publications

Domain formation in the type-II/1 superconductor niobium: Interplay of pinning, geometry, and attractive vortex-vortex interaction

Domain formation in the type-II/1 superconductor niobium: Interplay of pinning, geometry, and attractive vortex-vortex interaction

Fast neutron sensitivity for 3He detectors and comparison with Boron-10 based neutron detectors

Li-ion half-cells studied operando during cycling by small-angle neutron scattering

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