Full Angular Range Research Articles

Analysis of 11B + 13,14C scattering and 13C(11B, 10B)14C reaction data at E lab(11B) = 45 MeV using energy dependent optical model systematics for carbon isotopes

Existing data for 11B + 13,14C elastic and inelastic scattering at E lab(11B) = 45 MeV, as well as new data for the 13C(11B, 10B)14C reaction for transitions populating the ground state of 14C and the ground plus first four excited states of 10B, were analysed using the coupled-channels (CC) and coupled-reaction-channels (CRC) methods. A recently proposed energy dependent optical model (OM) potential for carbon isotopes, consisting of Woods-Saxon (WS) volume real and WS volume plus surface imaginary components, applied successfully to OM analyses of scattering from mid-mass (A > 27) and heavy target nuclei, was used to generate the distorted waves in the entrance and exit channels. The data analysed in this work cover the whole angular range, enabling the most important reaction mechanisms leading to the production of nuclei in the exit reaction channels to be established. For these light boron + carbon systems, a reasonable fit to both scattering and reaction data over the full angular range required some modification of the parameters of the OM potential extracted from the energy-dependent carbon systematics: omission of the surface imaginary part and a slight increase in the radius of the real part. Inclusion of a sufficient number of inelastic channels in a CC analysis of the 11B + 13,14C elastic scattering was shown to be important at mid-range scattering angles, while for the 13C(11B, 10B)14C reaction inclusion of two-step neutron transfers via low-lying excited states of 11B was required to give good overall agreement between the CRC calculations and the data. We suggest the analytical form of the global carbon OM potential may benefit from an additional parameterization of the radius of the real part and the depth of the surface imaginary part, dependent on the target mass number, to give better applicability to the analysis of scattering from light target nuclei.

Prototyping optimization-based image reconstructions from limited-angular-range data in dual-energy CT

Image reconstruction from data collected over full-angular range (FAR) in dual-energy CT (DECT) is well-studied. There exists interest in DECT with advanced scan configurations in which data are collected only over limited-angular ranges (LARs) for meeting unique workflow needs in certain practical imaging applications, and thus in the algorithm development for image reconstruction from such LAR data. The objective of the work is to investigate and prototype image reconstructions in DECT with LAR scans. We investigate and prototype optimization programs with various designs of constraints on the directional-total-variations (DTVs) of virtual monochromatic images and/or basis images, and derive the DTV algorithms to numerically solve the optimization programs for achieving accurate image reconstruction from data collected in a slew of different LAR scans. Using simulated and real data acquired with low- and high-kV spectra over LARs, we conduct quantitative studies to demonstrate and evaluate the optimization programs and their DTV algorithms developed. As the results of the numerical studies reveal, while the DTV algorithms yield images of visual quality and quantitative accuracy comparable to that of the existing algorithms from FAR data, the former reconstruct images with improved visualization, reduced artifacts, and also enhanced quantitative accuracy when applied to LAR data in DECT. Optimization-based, one-step algorithms, including the DTV algorithms demonstrated, can be developed for quantitative image reconstruction from spectral data collected over LARs of extents that are considerably smaller than the FAR in DECT. The theoretical and numerical results obtained can be exploited for prototyping designs of optimization-based reconstructions and LAR scans in DECT, and they may also yield insights into the development of reconstruction procedures in practical DECT applications. The approach and algorithms developed can naturally be applied to investigating image reconstruction from LAR data in multi-spectral and photon-counting CT.

4D-image reconstruction directly from limited-angular-range data in continuous-wave electron paramagnetic resonance imaging

Objective: We investigate and develop optimization-based algorithms for accurate reconstruction of four-dimensional (4D)-spectral-spatial (SS) images directly from data collected over limited angular ranges (LARs) in continuous-wave (CW) electron paramagnetic resonance imaging (EPRI). Methods: Basing on a discrete-to-discrete data model devised in CW EPRI employing the Zeeman-modulation (ZM) scheme for data acquisition, we first formulate the image reconstruction problem as a convex, constrained optimization program that includes a data fidelity term and also constraints on the individual directional total variations (DTVs) of the 4D-SS image. Subsequently, we develop a primal–dual-based DTV algorithm, simply referred to as the DTV algorithm, to solve the constrained optimization program for achieving image reconstruction from data collected in LAR scans in CW-ZM EPRI. Results: We evaluate the DTV algorithm in simulated- and real-data studies for a variety of LAR scans of interest in CW-ZM EPRI, and visual and quantitative results of the studies reveal that 4D-SS images can be reconstructed directly from LAR data, which are visually and quantitatively comparable to those obtained from data acquired in the standard, full-angular-range (FAR) scan in CW-ZM EPRI. Conclusion: An optimization-based DTV algorithm is developed for accurately reconstructing 4D-SS images directly from LAR data in CW-ZM EPRI. Future work includes the development and application of the optimization-based DTV algorithm for reconstructions of 4D-SS images from FAR and LAR data acquired in CW EPRI employing schemes other than the ZM scheme. Significance: The DTV algorithm developed may be exploited potentially for enabling and optimizing CW EPRI with minimized imaging time and artifacts by acquiring data in LAR scans.

On-Chip Frequency Tuning of Fast Resonant MEMS Scanner

The development and characterisation of a piezoelectric actuated high-frequency MEMS scanning mirror with on-chip frequency tuning capability is reported. The resonant scanner operates at frequencies in excess of 140 kHz, generating scan angles of 10° and 6° for two orthogonal movement modes with 40 V actuation. On-chip frequency tuning is achieved through electrothermal actuators fabricated adjacent to the mirror main suspension. The electrothermal actuators produce a global and local temperature increase which changes the suspension stiffness and therefore the resonant frequency. A resonance frequency tuning range of up to 5.5 kHz is achieved, with tuning dominant on only one of the two orthogonal scan movement modes. This opens the possibility for precise tuning of a 2D Lissajous scan pattern using a single resonant MEMS scanner with dual orthogonal resonant modes producing full frame update rates up to 20 kHz while retaining the full angular range of both resonant movement modes.

Erosion Rate Measurements for DART Spacecraft Ion Propulsion System

The Double Asteroid Redirection Test (DART) spacecraft was developed to provide the first measurement for orbital deflection of an asteroid upon intentional impact. The NEXT ion engine is part of the mission, on its maiden voyage. As part of the pre-launch risk reduction, erosion characteristics of the extraction grid system were evaluated using laser measurements of sputtered molybdenum atoms over the envelope of potential throttle conditions for the mission. Erosion rate dependence on propellant flow rate as well as relative density and directionality of molybdenum sputter from grid center to edge were measured. Sputtered atoms were found to have average radial velocity directed toward the engine perimeter and increasing with radial distance. The relative contribution of source and facility background gas and other sources of accelerator grid current was examined as well as the influence of several engine operating parameters. Facility background gas was found to influence engine operation more than a wall-mounted pressure gauge and typical assumptions about ingestion would indicate. Far-field flux was estimated over the full angular range based on the near-field relative density and velocity results and relying on quartz crystal microbalance data at one location to fix absolute numbers everywhere. The results substantially deepen knowledge and understanding of the complex grid erosion process of the engine and its lifetime, as grid failure via erosion is the normal life limiter. Study results are also relevant to thruster–spacecraft integration issues such as molybdenum deposition rate on solar cells and other spacecraft surfaces.

Rapid assessment of REBCO CC angular critical current density J c(B, T = 4.2 K, θ) using torque magnetometry up to at least 30 tesla

Detailed design of REBa2Cu3O (REBCO)-based magnets ideally relies on knowledge of the full angular and wide temperature range characterization of the critical current of the REBCO coated conductors (CC) at high magnetic fields. In practice, however, obtaining data by the commonly used electrical transport technique is expensive, tedious, and difficult, due to high critical current values that exceed 2000 A for -plane (θ = 90 deg). The conductors are often damaged during angular transport measurements at angles approaching the ab-plane. Therefore, so far, REBCO magnets have been designed without full data sets. Here, we present results for more than twenty samples of CC all made to the same advanced pinning specification produced by SuperPower Inc. For this, we employed torque magnetometry, benchmarking the results to transport measurements mostly made away from ab-plane, finding good agreement with scaling factors ≈1–1.3. What is striking is the huge variety of properties exhibited by the samples, even for CC made recently. Given the huge attention now being paid to the effects of screening currents and to the torques generated by offsets between the tape plane and the local magnetic field vector, our data set suggests some caution in detailed design of such magnets without having data of the type presented here.

First measurement of inclusive electron-neutrino and antineutrino charged current differential cross sections in charged lepton energy on argon in MicroBooNE

We present the first measurement of the single-differential $\nu_e + \bar{\nu}_e$ charged-current inclusive cross sections on argon in electron or positron energy and in electron or positron scattering cosine over the full angular range. Data were collected using the MicroBooNE liquid argon time projection chamber located off-axis from the Fermilab Neutrinos at the Main Injector beam over an exposure of $2.0\times10^{20}$ protons on target. The signal definition includes a 60 MeV threshold on the $\nu_e$ or $\bar{\nu}_e$ energy and a 120 MeV threshold on the electron or positron energy. The measured total and differential cross sections are found to be in agreement with the GENIE, NuWro, and GiBUU neutrino generators.

O18+Se76 elastic and inelastic scattering at 275 MeV

Background: An accurate description of the initial and final state interactions in the O18+Se76 collision is demanded by the NUMEN project. The study of single and double charge exchange nuclear reactions is the main purpose for NUMEN, since these can be used as tools to provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double-β decay. To date, the details of the optical potentials and nuclear response to isospin operators for many of the projectile-target systems proposed for the NUMEN double charge exchange studies are poorly known. The O18+Se76 case, here under study, is particularly relevant due to its connection with the Ge76 neutrinoless double-β decay. Purpose: In this work the authors want to characterize the initial-state interaction for the O18+Se76 reactions at 275 MeV incident energy determining the optical potential and evaluating the effect of couplings with the inelastic scattering on the elastic channel. Methods: The angular distributions of differential cross section were measured in the angular region between 4∘ and 22∘ in the center-of-mass reference frame. The cross sections were compared with theoretical calculations, that adopt different optical potentials. Coupling effects on the elastic channel were determined into the coupled channels formalism. Results: The excitation energy spectrum of the colliding nuclei and the cross section angular distributions were measured with satisfactory energy resolution. The elastic scattering cross section is not well reproduced in the full angular range explored when the optical model approach is adopted. A good agreement is found using coupled channel calculations. The initial state interaction for the O18+Se76 nuclear reactions at 275 MeV is determined. Conclusions: Coupled channels effects are crucial to obtain a good description of the measured elastic and inelastic channels cross sections, even at large transferred momenta where the optical model approach fails in reproducing the experimental data. The role of channel coupling could be relevant also in the analysis of other open reaction channels in the same collision and should be accounted for in double charge exchange analyses as well.Received 19 December 2020Revised 6 October 2021Accepted 10 November 2021DOI:https://doi.org/10.1103/PhysRevC.104.054610©2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDirect reactionsLow & intermediate energy heavy-ion reactionsNuclear reactionsNuclear structure & decaysNucleon-nucleon interactionsTransfer reactionsProperties59 ≤ A ≤ 896 ≤ A ≤ 19TechniquesCollective modelsNuclear data analysis & compilationNuclear reaction analysisOptical, coupled-channel & distorted wave modelsSpectrometers & spectroscopic techniquesNuclear Physics

Dual-energy CT imaging with limited-angular-range data

In dual-energy computed tomography (DECT), low- and high-kVp data are collected often over a full-angular range (FAR) of 360°. While there exists strong interest in DECT with low- and high-kVp data acquired over limited-angular ranges (LARs), there remains little investigation of image reconstruction in DECT with LAR data. Objective: we investigate image reconstruction with minimized LAR artifacts from low- and high-kVp data over LARs of ≤180° by using a directional-total-variation (DTV) algorithm. Methods: image reconstruction from LAR data is formulated as a convex optimization problem in which data-ℓ 2 is minimized with constraints on image’s DTVs along orthogonal axes. We then achieve image reconstruction by applying the DTV algorithm to solve the optimization problem. We conduct numerical studies from data generated over arcs of LARs, ranging from 14° to 180°, and perform visual inspection and quantitative analysis of images reconstructed. Results: monochromatic images of interest obtained with the DTV algorithm from LAR data show substantially reduced artifacts that are observed often in images obtained with existing algorithms. The improved image quality also leads to accurate estimation of physical quantities of interest, such as effective atomic number and iodine contrast concentration. Conclusion: our study reveals that from LAR data of low- and high-kVp, monochromatic images can be obtained that are visually, and physical quantities can be estimated that are quantitatively, comparable to those obtained in FAR DECT. Significance: as LAR DECT is of high practical application interest, the results acquired in the work may engender insights into the design of DECT with LAR scanning configurations of practical application significance.

Elastic scattering and electronic excitation in positron interactions with neon

We report measurements of low energy positron scattering from neon, with the first measurements of absolute differential cross sections (DCSs) and of state-selective electronic excitation. These measurements are compared to calculations using the relativistic optical potential (ROP) technique, as well as other recently published theoretical calculations. At the lowest energies, experimental DCS data are fitted to extract scattering phase shifts, which can be compared to theoretical values and also used to generate DCS values over the full angular range. For the most part we find good accord in the two descriptions of the scattering processes, with some key disagreements. An analysis of possible sources of systematic error has also been presented, in light of the discrepancies.

On reaction mechanisms in deuteron–proton elastic scattering

The deuteron–proton elastic scattering is considered in the full angular range at the two deuteron energies of 880 MeV and 1200 MeV. Four reaction mechanisms are taken into account. The effects of various contributions are analyzed. The obtained theoretical predictions are compared with the existing experimental data for the differential cross section, and vector $$A_y$$ and tensor $$A_{yy}$$ analyzing powers.

Systematic analysis of elastic α scattering on [formula omitted] nuclei around the Coulomb barrier

Alpha elastic scattering angular distributions on target nuclei 118, 124Sn and 120-130Te at energies near the Coulomb barrier are analyzed. We used three versions of the nuclear optical model potentials (OMP) to analyze twenty-nine data sets. JLM and the density and energy-dependent DDM3Y1 with finite range exchange term effective interactions were used to generate these potentials. Two real folded potentials based on JLM and DDM3Y1 effective interactions supplied with the conventional Wood–Saxon (WS) imaginary potential are used in the cross sections calculations. These potentials are denoted as JLM-R and DDM3Y1-FR, respectively. In addition, we used the full complex folded OMP, denoted as JLM-RI, to analyze the same data. These potentials successfully predict the cross section of the systems under study. We found that the JLM-R and DDM3Y1-FR could reproduce the measured cross sections over the full angular range very well compared to microscopic JLM-RI potential. Our calculated potentials have a clear energy dependence and in addition a weak target mass dependence. The total reaction cross section and volume integral are investigated in comparison to previous studies. The derived potentials are very promising for the construction of a new global α-nucleus potential and provide new parameters of α–induced reactions and scattering at the energy range 17–27 MeV.

Laboratory measurements of light scattering matrices for resuspended small loess dust particles at 532 nm wavelength

The Chinese Loess Plateau (CLP) is one of the sources or a recharge station of Asian dust. In this study, scattering matrices for two loess samples collected from different regions of CLP were measured at a wavelength of 532 nm from 5° to 160° scattering angles. Other necessary characteristics were also analyzed, like particle size distribution, chemical composition, refractive index and micro morphology. Synthetic scattering matrices for different loess samples were defined over full angular range of scattering by combining Lorenz–Mie calculations as well as extrapolations or interpolations of measurement results. From the perspective of constructing an average scattering matrix suitable for loess, similarities and discrepancies between synthetic scattering matrices for loess samples collected from CLP and Hungary were analyzed. Although different light wavelengths were employed in experimental measurements of CLP samples and Hungary loess, matrix elements for these three samples show comparable angular distributions and are confined to relatively limited domains, respectively. Then, an average synthetic scattering matrix targeted for loess dust was proposed for spectral range from 441.6 to 632.8 nm, which is valuable for multispectral and multi-angle satellite remote sensing as well as radiative transfer calculations. When compared with average scattering matrix of different kinds of mineral dust proposed previously, it can be seen clearly that the domains covered by loess samples and various kinds of mineral dust are highly coincident, while the areas covered by loess samples are more narrow.

Methodology for evaluating the information distribution in small angle scattering from periodic nanostructures

Optimizing the extraction of information from x-ray measurements while minimizing exposure time is an important area of research in a variety of fields. The semiconductor industry is reaching a point where the traditional optical metrologies need to be augmented in order to better resolve the critical dimensions of structures with feature sizes below 10 nm. Critical dimension small angle x-ray scattering (CDSAXS) is one measurement technique that is capable of characterizing detailed features of periodic nanostructures. As currently implemented, the measurement utilizes the combined scattering from up to 60 different angles. Reducing the number of angles would dramatically improve the feasibility of CDSAXS for implementation in a fabrication setting, but currently there are no clear guidelines as to which angles provide the most information to minimize the uncertainty in the shape of the target structure while maximizing the throughput. In order to develop guidelines for optimizing the angle selection, simulation studies were conducted on a wide variety of structures with subsets of the full angular range to identify which angles minimized the overall shape uncertainty. Analyzing sets of two angle pairs (including all combinations between 0 deg and 60 deg) provides guidance on which angles best constrain the samples. For select samples, higher numbers of angles were included to explore the impact of additional information on the model uncertainty. In general, low angles (<3 deg) best contributed to minimizing the line-width uncertainty, while higher angles near high curvature regions of the scattering profile best constrained the height of the structure. The minimum uncertainty was generally achieved with combinations of the two. This simulation approach can be used to minimize the number of angles measured on real samples and significantly reduce the measurement time.

Effects of environmental and operational variability on the spectrally selective properties of W/WAlN/WAlON/Al2O3-based solar absorber coating

The stability of solar selective absorber coatings in hostile environments (e.g., humid condition, corrosive medium, longer exposure at elevated temperature) needs to be critically assessed to ensure durability of such coatings. In the present work, magnetron sputtered W/WAlN/WAlON/Al2O3-based absorber coating with a high absorptance (0.958) and low emittance (82 °C) has been tested in humid and corrosive environments. The selectivity (absorptance/emittance) of the coating did not change after keeping it in 95% humidity at 37 °C for 400 h. Corrosion study in 3.5% NaCl solution reveals that this novel multilayer coating has a better corrosion resistance than that of uncoated stainless steel (SS) substrate. The nanoindentation test on the coating indicates that it has a hardness of 9.6 ± 0.5 GPa. The performance of the coating did not degrade after heat treatment at 350 °C in air for 1000 h. Additionally, the activation energy for degradation has been determined to predict the stability of the coating at high temperature. Further, the normal spectral emissivity of the tandem solar absorber was measured in the full angular range from 200 to 500 °C. The results of emissivity measurements by varying observation angles are analysed using numerical integration to obtain the total hemispherical emissivity. In summary, W/WAlN/WAlON/Al2O3 stack is an attractive candidate absorber coating for photo-thermal conversion systems.

Thick Secondary Phase Pinning-Enhanced YBCO Films on Technical Templates

The critical current I c (B) of YBa 2 Cu 3 O 7-δ (YBCO) coated conductors can be increased by growing thicker superconductor layers as well as improving the critical current density J c (B) by the incorporation of artificial pinning centers. We studied the properties of pulsed laser deposited BaHfO 3 (BHO)doped YBCO films with thicknesses of up to 5 μm on buffered rolling-assisted biaxially textured Ni-5 at% W tape and alternating beam assisted deposition textured Yttrium-stabilized ZrO 2 layers on stainless steel. X-Ray diffraction confirms the epitaxial growth of the superconductor on the buffered metallic template. BHO additions reduce the film porosity and lower the probability to grow misoriented grains, hence preventing the J c decrease observed in undoped YBCO films with thicknesses >2 μm. Thereby, a continuous increase in I c at 77 K is achieved. A mixed structure of secondary phase nanorods and platelets with different orientations increases J c (B) in the full angular range and simultaneously lowers the J c anisotropy compared to pristine YBCO.

A Gaussian extension for Diffraction Enhanced Imaging

Unlike conventional x-ray attenuation one of the advantages of phase contrast x-ray imaging is its capability of extracting useful physical properties of the sample. In particular the possibility to obtain information from small angle scattering about unresolvable structures with sub-pixel resolution sensitivity has drawn attention for both medical and material science applications. We report on a novel algorithm for the analyzer based x-ray phase contrast imaging modality, which allows the robust separation of absorption, refraction and scattering effects from three measured x-ray images. This analytical approach is based on a simple Gaussian description of the analyzer transmission function and this method is capable of retrieving refraction and small angle scattering angles in the full angular range typical of biological samples. After a validation of the algorithm with a simulation code, which demonstrated the potential of this highly sensitive method, we have applied this theoretical framework to experimental data on a phantom and biological tissues obtained with synchrotron radiation. Owing to its extended angular acceptance range the algorithm allows precise assessment of local scattering distributions at biocompatible radiation doses, which in turn might yield a quantitative characterization tool with sufficient structural sensitivity on a submicron length scale.

Scattering of α-particles and 3He on 16O nuclei and its excitation mechanism at energies near 50MeV

Elastic and inelastic scattering of [Formula: see text]-particles at 48.1[Formula: see text]MeV and 3He at 60[Formula: see text]MeV on [Formula: see text]O nuclei has been measured with excitation of states at 6.05 (0[Formula: see text])–6.13 (3[Formula: see text])[Formula: see text]MeV, 6.92 (2[Formula: see text])–7.12 (1[Formula: see text])[Formula: see text]MeV and 8.87 (2[Formula: see text])[Formula: see text]MeV. The center-of-mass beam momenta are the same for these two strongly absorbed particles. Analysis of angular distributions was performed in the frameworks of the optical model, the coupled channels method and the Distorted Wave Born Approximation (DWBA). A good description of experimental data was obtained over the full angular range without taking into account the spin-orbit interaction and the cluster transfer mechanism with real potentials that have volume integrals of about 400[Formula: see text]MeV fm3. Collective and microscopic models were used in the analysis of the inelastic scattering. The values of the octupole deformation lengths were extracted. It is shown that nuclear rainbow effects appear not only in the elastic, but also in the inelastic scattering with excitation of the 3[Formula: see text] state of [Formula: see text]O.

Intrinsic and extrinsic pinning in NdFeAs(O,F): vortex trapping and lock-in by the layered structure.

Fe-based superconductors (FBS) present a large variety of compounds whose properties are affected to different extents by their crystal structures. Amongst them, the REFeAs(O,F) (RE1111, RE being a rare-earth element) is the family with the highest critical temperature Tc but also with a large anisotropy and Josephson vortices as demonstrated in the flux-flow regime in Sm1111 (Tc ∼ 55 K). Here we focus on the pinning properties of the lower-Tc Nd1111 in the flux-creep regime. We demonstrate that for H//c critical current density Jc at high temperatures is dominated by point-defect pinning centres, whereas at low temperatures surface pinning by planar defects parallel to the c-axis and vortex shearing prevail. When the field approaches the ab-planes, two different regimes are observed at low temperatures as a consequence of the transition between 3D Abrikosov and 2D Josephson vortices: one is determined by the formation of a vortex-staircase structure and one by lock-in of vortices parallel to the layers. This is the first study on FBS showing this behaviour in the full temperature, field, and angular range and demonstrating that, despite the lower Tc and anisotropy of Nd1111 with respect to Sm1111, this compound is substantially affected by intrinsic pinning generating a strong ab-peak in Jc.

X-Ray Scattering Analysis of the Morphology of TiO2 (B) Nanoparticles

The morphological characteristics of a nanomaterial, i.e., geometric shape and dimension, and the arrangement of atoms, which both vary depending on specific nanostructures, have a considerable impact on properties such as electronic structure, ionic diffusion, and surface structure. It is, therefore, essential to determine the nanomorphology of the electrode materials so as to link shape with the electrochemical performance. Conventional microscopy methods used to characterize the morphology of nanomaterials sometimes involve practical challenges arising from the aggregation of nanoscopic structure. In order to determine the morphology of a TiO2 (B) nanoparticle sample that shows excellent electrochemical performance1,2, we have performed a comprehensive X-ray scattering analysis of SAXS, PDF and XRPD data. The scattering pattern within a particular angular range encodes distinct structural features of the materials ranging from mesoscale to nanoscale. The combination of small- and wide-angle measurements therefore covers a full angular range that enables us to access a complete set of morphological and structural characteristics including size and shape via SAXS, particle asymmetry and long-range structure via XRPD, and short-range atomic ordering via PDF. From the analyses, we conclude that the particles are oblate-shaped, contracted along the [010] direction. This particular morphology provides not only a plausible rationale for the excellent electrochemical behavior of these TiO2(B) nanoparticles, but also a structural foundation to model the strain-driven distortion induced by lithiation. A more complex displacement model incorporating this lithiation-induced strain was developed making use of the oblate particle model. It clearly shows the importance of determining the morphology of the nanoparticle so as to understand the lithiation mechanism and rationalize the rate performance of nanostructured materials. Reference: [1] Ren, Y.; Liu, Z.; Pourpoint, F.; Armstrong, A. R.; Grey, C. P.; Bruce, P. G. Angew. Chem. Int. Ed. 51 (2012) 2164-2167. [2] Andreev, Y. G.; Panchmatia, P. M.; Liu, Z.; Parker, S. C.; Islam, M. S.; Bruce, P. G. J. Am. Chem. Soc. 136 (2014) 6306-6312.