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Measurements and methods of mitigation for small-angle neutron scattering instrument background caused by extraneous scattering from surfaces are presented., Measurements, calculations and design ideas to mitigate background caused by extraneous scattering in small-angle neutron scattering (SANS) instruments are presented. Scattering includes processes such as incoherent scattering, inelastic scattering and Bragg diffraction. Three primary sources of this type of background are investigated: the beam stop located in front of the detector, the inside lining of the detector vessel and the environment surrounding the sample. SANS measurements were made where materials with different albedos were placed in all three locations. Additional measurements of the angle-dependent scattering over the angular range of 0.7π–0.95π rad were completed on 16 different shielding materials at five wavelengths. The data were extrapolated to cover scattering angles from π/2 to π rad in order to estimate the materials’ albedos. Modifications to existing SANS instruments and sample environments to mitigate extraneous scattering from surfaces are discussed.

Calculations and desmearing of different multiple scattering effects for the small-angle scattering technique using the software package MuScatt are presented., This article deals with multiple scattering effects that are important for the method of small-angle neutron scattering (SANS). It considers three channels for the coherent elastic, the incoherent elastic and the incoherent inelastic scattering processes. The first channel contains the desired information on the experiment. Its multiple scattering effects can be desmeared, as shown in the later sections of the article. The other two channels display a nearly constant background as a function of the scattering angle. The incoherent elastic scattering is treated by the theory of Chandrasekhar, allowing for multiple scattering even at large scattering angles. The transfer to a single representative thermalized wavelength by the inelastic scattering – as a simplification – is assumed to happen by a single scattering event. Once the transition to this altered wavelength has happened, further incoherent multiple scattering is considered. The first part of the paper deals with the multiple scattering effects of light water. In the later part of the article, deconvolution algorithms for multiple scattering and instrumental resolution of the elastic coherent signal as implemented in the program MuScatt are described. All of these considerations are interesting for both reactor-based instruments with velocity selectors and time-of-flight SANS instruments and may improve the reliability of the data treatment.

We report on the measurements of the spin-wave stiffness A and its temperature dependence close to T C for two compounds: FeGe and the solid solution Fe 0.8 Mn 0.2 Ge. The small-angle neutron scattering was used to detect the inelastic scattering in the magnetic field above the transition from the conical to the field-polarized state. This inelastic contribution is shaped as two circles on a neutron scattering map. Their radius is directly related to the spin wave stiffness A that decreases with a temperature but has a finite value at T c for both compounds. Since the softening of spin waves near T c , which is expected for a second-order phase transition, is not observed, we make a conclusion about the transition as having a first-order nature.

Scattering experiments performed with the Rensselaer Polytechnic Institute Linear Accelerator measured elastic and inelastic scattering from an elemental iron sample. Eight liquid scintillator (EJ-301) proton recoil fast neutron detectors were positioned at several angles 0.5 m from the scattering sample. Data were measured using neutron time-of-flight in the energy range from 0.5 to 20 MeV, and pulse shape analysis was used to discriminate neutrons from gamma-rays. Nuclear data evaluations were compared to experimental data using Monte Carlo calculations. Below 2 MeV two new techniques were developed: a method which assessed inelastic-to-elastic scattering ratios and a method to determine the contribution from neutrons after only elastic scattering. These techniques, along with time-of-flight results, may help identify specific reactions that account for differences between evaluations and experimental data.

A Monte Carlo method for angle scattering of electrons in air that accommodates the small-angle multiple scattering and larger-angle single scattering limits is introduced. The algorithm is designed for use in a particle-in-cell simulation of electron transport and electromagnetic wave effects in air. The method is illustrated in example calculations.

Results of experimental verification of results on neutron inelastic scattering cross section for iron obtained in measurements of spectra of neutrons undergoing inelastic scattering at incident neutron energies of 6.0, 7.0 and 8.0 MeV and their calculations within the framework of statistical theory of nuclear reactions and direct interactions are presented. Description is given of the methodology of measurements and simulation calculations. Spectra of neutrons undergoing inelastic scattering obtained for iron in the process of experiments are analyzed in comparison with calculated data. New measurements of neutron inelastic scattering spectra and their analysis within the framework of contemporary modeling understanding allowed formulating proposal on introduction of corrections in the indigenous BROND-2.2 library of recommended evaluated neutron data and insignificant corrections in the most recent version of the library BROND-3.

Current Monte Carlo codes use one of three models: (1) the asymptotic scattering model, (2) the free gas scattering model, or (3) the S(alpha,beta) model, depending on the neutron energy and the specific Monte Carlo code. This thesis addresses the consequences of using the free gas scattering model, which assumes that the neutron interacts with atoms in thermal motion in a monatomic gas in thermal equilibrium at material temperature, T. Most importantly, the free gas model assumes the scattering cross section is constant over the neutron energy range, which is usually a good approximation for light nuclei, but not for heavy nuclei where the scattering cross section may have several resonances in the epithermal region. Several researchers in the field have shown that the exact resonance scattering model is temperature-dependent, and neglecting the resonances in the lower epithermal range can under-predict resonance absorption due to the upscattering phenomenon mentioned above, leading to an over-prediction of keff by several hundred pcm. Existing methods to address this issue involve changing the neutron weights or implementing an extra rejection scheme in the free gas sampling scheme, and these all involve performing the collision analysis in the center-of-mass frame, followed by a conversion back to the laboratory frame to continue the random walk of the neutron. The goal of this thesis was to develop a sampling methodology that (1) accounted for the energy-dependent scattering cross sections in the collision analysis and (2) was performed in the laboratory frame, avoiding the conversion to the center-of-mass frame. The energy dependence of the scattering cross section was modeled with even-ordered polynomials (2nd and 4th order) to approximate the scattering cross section in Blackshaw’s equations for the moments of the differential scattering PDFs. These moments were used to sample the outgoing neutron speed and angle in the laboratory frame on-the-fly during the random walk of the neutron. Results for criticality studies on fuel pin and fuel assembly calculations using methods developed in this dissertation showed very close comparison to results using the reference Doppler-broadened rejection correction (DBRC) scheme.

Angular distributions of the elastic and inelastic scattering of 15N ions by 7Li nuclei were measured at the energy E lab ( N 15 ) = 81 MeV ( E c.m. = 25.77 MeV ) . The data were analyzed within the coupled-reaction-channels method. The elastic and inelastic scattering, spin reorientations of 7Li as well as the more important one- and two-step transfer reactions were included in the channels-coupling scheme. The parameters of Li 7 + N 15 optical potential of Woods–Saxon form as well as deformation parameters of these nuclei were deduced. The analysis showed that the forward angle elastic scattering is dominated by pure potential scattering whereas the middle and large angle scattering gets a contribution from the ground state reorientation of 7Li. Contributions from particle transfers were negligible for the present scattering system. The Li 7 + N 15 elastic scattering was compared with that of Li 7 + N 14 at the energies E lab ( N 14 ) = 80 MeV and 110 MeV. Different contributions to the elastic scatterings from other nuclear processes are shown to be responsible for the isotopic difference observed in the large angle scattering.

The differences in the vibrational spectra of a condensed matter between inelastic neutron scattering and photon scattering originate from the different corresponding interaction mechanisms. However, investigators used to ignore them due to difficulties to analyse theoretically. Herein, we devise an approach to link neutron scattering with photon scattering experiments by computing simulation methods and shed light on new physical insights for the assignments of crystalline materials. By using the first-principles method based on density functional theory (DFT), the vibrational spectrum of ice VIII is investigated. Comparisons between the computing vibration modes and the experimental data of ice VIII, i.e., Raman and neutron scattering data, mutually validate the reliability. The assignments of the dynamic process of 33 normal modes at the Brillouin zone (BZ) center are precisely illustrated from the vibrational analysis based on CASTEP code. The physical insights for special vibration modes are discussed individually as well as in terms of the correlated peak from neutron and Raman scattering.

The photogeneration process in polymer-fullerene organic solar cells relies strongly on the nanostructure and on the nano/picosecond dynamics occurring in these complex blends. Elastic and inelastic neutron scattering techniques are valuable tools with which to investigate those features in the appropriate time and space domains. In particular, quasi-elastic neutron scattering (QENS) connects useful structural and dynamical information by the measurement of dynamical incoherent (single particle) fluctuations in soft materials as a function of lengthscale. Extraction of these fluctuation rates can, however, be hampered by the presence of coherent contributions, originating from elastic scattering, and/or inelastic scattering modes which overlap in the space/time domain with the incoherent single-particle motions. As we have already seen in a previous study [1], this happens in poly(3-hexylthiophene) (P3HT) and [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) solid blends, in which the coherent contribution arising from the PCBM crystalline phase seems to affect the interpretation of the polymer dynamics. Here, we utilise neutron polarisation analysis as an effective tool to separate coherent and incoherent contributions and make QENS data analysis of these blends more reliable.

Multiple coulomb scattering and energy loss are well known phenomena experienced by charged particles as they traverse a material. However, from recent measurements by the MuScat collaboration, it is known that the available simulation codes (GEANT4, for example) overestimate the scattering of muons in low Z materials. This is of particular interest to the Muon Ionization Cooling Experiment (MICE) collaboration which has the goal of measuring the reduction of the emittance of a muon beam induced by energy loss in low Z absorbers. MICE took data without magnetic field suitable for multiple scattering measurements in the fall of 2015 with the absorber vessel filled with Xenon and in the spring of 2016 using a lithium hydride absorber. The scattering data are compared with the predictions of various models, including the default GEANT4 model. In the fall of 2016 MICE took data with magnetic fields on and measured the energy loss of muons in a lithium hydride absorber. These data are also compared with model predictions and with the Bethe-Bloch formula., Proceedings of the 11th Workshop on Beam Cooling and Related Topics, COOL2017, Bonn, Germany

The magnitude of the single-crystal elastic constant c44 in the MAX phase Ti3SiC2 is under debate. In this paper, estimates for the magnitude of c44 for MAX phases Ti3AlC2 and Ti3SiC2 are determined from a partially oriented polycrystalline sample via coherent inelastic neutron scattering. The largely quasi-isotropic nature of these Mn+1AXn phase elastic constants as previously predicted by density functional theory calculations is confirmed experimentally for Ti3AlC2 to be c44 = 115.3 ± 30.7 GPa. In contrast, Ti3SiC2 is confirmed to be shear stiff with c44 = 402.7 ± 78.3 GPa supporting results obtained by earlier elastic neutron diffraction experiments.

The neutron inelastic scattering cross section of In 115 has been measured by the activation technique at neutron energies of 2.95, 3.94, and 5.24 MeV with the neutron capture cross sections of Au 197 as an internal standard. The effects of multiple scattering and flux attenuation were corrected using the Monte Carlo code GEANT4. Based on the experimental values, the In 115 neutron inelastic scattering cross sections data were theoretically calculated between the 1 and 15 MeV with the TALYS software code, the theoretical results of this study are in reasonable agreement with the available experimental results.

That incoherent scattering from protiated molecular liquids adds a constant background to the measured scattering intensity is well-known, but less appreciated is the fact that coherent scattering is also induced by the presence of hydrogen in a deuterated liquid. In fact, the scattering intensity can be very sensitive, in the small-q region, with respect to the amounts and distribution of residual H in the system. We used 1,4-dioxane liquid to demonstrate that the partial structure factors of the HD and DD atom pairs contribute significantly to intermolecular scattering and that uncertainty in the extent of deuteration account for discrepancies between simulations and measurements. Both contributions to uncertainty have similar magnitudes: scattering interference of the hydrogen-deuterium pair, and complementary interference from the deuterium-deuterium pair by virtue of chemical inhomogeneity. This situation arises in practice since deuteration of liquids is often 99% or less. A combined experimental and extensive computational study of static thermal neutron scattering of 1,4-dioxane demonstrates the foregoing. We show, through simulations, that the reason for the differences is the content of protiated dioxane (vendors quote 1%). We estimate that up to 5% (at 298 K and at 343 K) protiated molar fraction may be involved in generating the scattering differences. Finally, we find that the particular distribution of hydrogen in the protiated molecules affects the results significantly; here, we considered molecules to be either fully protiated or fully deuterated. This scenario best reconciles the computational and experimental results, and leads us to speculate that the deuteration synthesis process tends to leave a molecule either fully deuterated or fully protiated. Although we have used 1,4-dioxane as a model liquid, the effects described in this study extend to similar liquids, and similar systematic experimental/computational studies can be performed to either understand measurements or calibrate/validate molecular dynamics models.

Analytical properties of Compton profiles are used in order to simplify the analysis of neutron Compton scattering experiments. In particular, the possibility to fit the difference of Compton profiles is discussed as a way to greatly decrease the level of complexity of the data treatment, making the analysis easier, faster and more robust. In the context of the novel method proposed, two mathematical models describing the shapes of differenced Compton profiles are discussed: the simple Gaussian approximation for harmonic and isotropic local potential, and an analytical Gauss–Hermite expansion for an anharmonic or anisotropic potential. The method is applied to data collected by VESUVIO spectrometer at ISIS neutron and muon pulsed source (UK) on Copper and Aluminium samples at ambient and low temperatures.

Angular distributions of the 9 Be + 15 N elastic and inelastic scattering were measured at E lab ( 15 N) = 84 MeV ( E c.m. = 31.5 MeV) for the 0–6.76 MeV states of 9 Be and 0–6.32 MeV states of 15 N. The data were analyzed within the optical model and coupled-reaction-channels method. The elastic and inelastic scattering, spin reorientations of 9 Be in ground and excited states and 15 N in excited states as well as the most important one- and two-step transfer reactions were included in the channels-coupling scheme. The parameters of the 9 Be + 15 N optical potential of Woods–Saxon form as well as deformation parameters of these nuclei were deduced. The analysis showed that the 9 Be + 15 N pure potential elastic scattering dominates at the forward angles whereas the ground state spin reorientation of 9 Be gives a major contribution to the elastic scattering cross sections at the large angles. Contributions from particle transfers are found to be negligible for the present scattering system.

Organic thin films that have no overall in-plane directional ordering often nonetheless produce anisotropic scattering patterns that rotate with the polarization of incident resonant X-rays. Isotropic symmetry is broken by local correlations between molecular orientation and domain structure. Such examples of molecular alignment at domain interfaces and within the bulk of domains, which are both critical to fields such as organic electronics, are simulated and compared with experimental scattering. Anisotropic scattering patterns are found to allow unambiguous identification of the mechanism of local molecular orientation correlations and, as such, promise to be both distinct and complementary to isotropic scattering intensity as a general measure of thin film microstructure.

Alkaline-earth beryllium and magnesium oxides are fundamental materials in nuclear industry and thermal neutron scattering applications. The calculation of the thermal neutron scattering cross sections requires a detailed knowledge of the lattice dynamics of the scattering medium. The vibrational properties of BeO and MgO are studied using first-principles calculations within the frame work of the density functional perturbation theory. Excellent agreement between the calculated phonon dispersion relations and the experimental data have been obtained. The phonon densities of states are utilized to calculate the scattering laws using the incoherent approximation. For BeO, there are concerns about the accuracy of the phonon density of states used to generate the current ENDF/B-VII.1 libraries. These concerns are identified, and their influences on the scattering law and inelastic scattering cross section are analyzed. For MgO, no up to date thermal neutron scattering cross section ENDF library is available, and our results represent a potential one for use in different applications. Moreover, the BeO and MgO efficiencies as neutron filters at different temperatures are investigated. BeO is found to be a better filter than MgO, especially when cooled down, and cooling MgO below 77 K does not significantly improve the filter’s efficiency.

The Extreme Environment Diffractometer is a neutron time-of-flight instrument, designed to work with a constant-field hybrid magnet capable of reaching fields over 26 T, unprecedented in neutron science; however, the presence of the magnet imposes both spatial and technical limitations on the surrounding instrument components. In addition to the existing diffraction and small-angle neutron scattering modes, the instrument will operate also in an inelastic scattering mode, as a direct time-of-flight spectrometer. In this paper we present the Monte Carlo ray-tracing simulations, the results of which illustrate the performance of the instrument in the inelastic-scattering mode. We describe the focussing neutron guide and the chopper system of the existing instrument and the planned design for the instrument upgrade. The neutron flux, neutron spatial distribution, divergence distribution and energy resolution are calculated for standard instrument configurations.

Measurements of neutron elastic and inelastic scattering cross sections from 23Na have been performed for sixteen incident neutron energies between 1.5 and 4.5 MeV. These measurements were complemented by γ-ray excitation functions using the ( n , n ′ γ ) reaction to include excited levels not resolved in the neutron detection measurements. The time-of-flight (TOF) technique was employed for background reduction in both neutron and γ-ray measurements and for energy determination in neutron detection measurements. Previous reaction model evaluations relied primarily on neutron total cross sections and four (n, n0) and (n, n1) angular distributions in the 5 to 9 MeV range. The inclusion of more inelastic channels and measurements at lower incident neutron energies provide additional information on direct couplings between elastic and inelastic scattering as a function of angular momentum transfer. Reaction model calculations examining collective direct-coupling and compound absorption components were performed.

We present an extensive theoretical study of the optical properties of hollow polymer particles (HPP) dispersed into a polymer resin as functions of their structure and volume-filling fraction. We show that a dependent light scattering model predicts the occurrence of three different light propagation regimes, the existence of which is consistent with experimental data gathered in the literature. We then analyze the effect of the polymer shell thickness on the magnitude of the near-field and far-field dependent light scattering phenomena. We also discuss and compare the variation of the scattering efficiency of Ropaque™, measured in our laboratory, as a function of the pigment volume-filling fraction, with dependent light scattering model. In particular, we show that in the case of HPP, quasi-linear variation of the scattering efficiency as a function of the particle volume-filling fraction is not an undeniable indication of the absence of electromagnetic couplings in the system. Finally, we used a solution of the radiative transfer equation to compare the prediction of the opacity of several simple paint films when a dependent light scattering model is used instead of the independent scattering approximation to calculate the optical properties of the films at a local scale.

Electron scattering in the possible Δ1 models of the conduction band in germanium crystals formed by hydrostatic or uniaxial pressure is investigated. On the basis of the theory of anisotropic scattering, the temperature dependences of the anisotropy parameter of the relaxation times and electron mobility for these models under conditions of scattering at impurity ions, as well as at acoustic and intervalley phonons are obtained. Analysis of the temperature dependences indicates that, in the temperature range of 77–300 K, intervalley scattering becomes substantial. Only for the Δ1 model formed by uniaxial pressure along the crystallographic direction [100], the electron scattering at intervalley phonons, which correspond to the g transitions, is minor with respect to scattering at acoustic phonons (the intravalley scattering) and impurity ions.

We address the reactivity of lithiated graphite–anode material for Li-ion batteries with standard organic solvents used in batteries (ethylene carbonate and dimethyl carbonate) by following changes in neutron scattering signals. The reaction produces a nanosized layer, the solid-electrolyte interphase (SEI), on the graphite particles. We probe the structure and chemistry of the SEI using small-angle neutron scattering (SANS) and inelastic neutron scattering. The SANS results show that the SEI fills 20–30 nm sized pores, and inelastic scattering experiments with H/D substitution show that this “chemical” SEI is primarily organic in nature; that is, it contains a large amount of hydrogen. The graphite–SEI particles show surface fractal scattering characteristic of a rough particle–void interface and are interconnected. The observed changes in the SEI structure and composition provide new insight into SEI formation. The chemically formed SEI is complementary and simpler in composition to the electrochemicall...

Inelastic neutron scattering experiments were performed on polycrystalline samples of NdFeAsO0.85F0.15over a wide temperature range (3 K–250 K). Based on the analysis of the experimental data, a Nd3+CF energy level scheme is proposed to give a consistent explanation about the observed CF transitions. The observed extra ground-state CF transitions could not be simply explained by the transitions between five Kramers doublets split from the Nd3+ 4I9/2ground state in theC4vpoint symmetry. A reliable explanation would be a superposition of crystal fields due to different local symmetries around the Nd3+ions induced by the fluorine doping.

The elastic scattering cross-sections for α particles from nitrogen at a scattering angle of 83.6° were measured in the energy range of 2.0–5.4 MeV, and the nitrogen recoil cross-sections at a recoil angle of 40° were derived from the scattering cross-sections. Simultaneous measurements of scattering cross-sections at a scattering angle of 165° were also performed to validate the measurements. The obtained recoil cross-section data are essential for the quantitative examination of nitrogen through time-of-flight elastic recoil detection analysis with He beams.

Properties of neutrons, in particular high penetration depth for most materials, make them very powerful for studying matter under extreme conditions, e.g. high pressures or magnetic fields. A new generation of high power spallation neutron sources, such as the existing SNS and J-Parc and the coming ESS, brings neutron scattering in extreme environments to a completely new level. Indeed, measurements of smaller samples, use of more complex equipment and neutron instruments optimized for operation with extreme sample environment become readily available. The latter is actually one of the most important factors contributing to the field. In this paper a novel concept of an instrument for extreme environments at the ESS is presented. The main feature of the Extreme Conditions Instrument is its multi-purpose nature. It is not optimized for a single scattering technique but combines in a balanced way elastic (Diffraction and Small Angle Neutron Scattering) and inelastic capabilities. Such a concept enables effective combination of neutron scattering with a state-of-the-art sample environment independent of the complexity, dimensions and transportability of the latter. In addition, all available types of neutron experiments can be performed at the same thermodynamic conditions. The instrument concept has been verified by Monte-Carlo ray-tracing simulations and the results for instrument operation modes are compared with world-class instruments.

The vibrational spectra of hydrogen and the parameters of H jump motion in the hexagonal Th 2 Ni 17 -type compounds Ho 2 Fe 17 H 4 and Y 2 Fe 17 H 4.2 have been studied by means of inelastic and quasielastic neutron scattering. It is found that hydrogen atoms occupying interstitial Ho(Y) 2 Fe 2 sites in both compounds participate in the fast localized jump motion over the hexagons formed by these tetrahedral sites. The temperature dependence of the H jump rate is well described by the Arrhenius law over wide T ranges (100–340 K for Ho 2 Fe 17 H 4 and 140–360 K for Y 2 Fe 17 H 4.2 ) with the activation energies of 54 (4) meV and 84 (7) meV, respectively. For Ho 2 Fe 17 H 4 , the localized hydrogen jump motion is found to be the fastest among all R 2 Fe 17 hydrides studied so far. At room temperature, the H jump rate in Ho 2 Fe 17 H 4 derived from our quasielastic neutron scattering data reaches 6.4 × 10 11 s −1 .

The level structure of $^{134}\mathrm{Xe}$ was studied with the inelastic neutron scattering reaction followed by $\ensuremath{\gamma}$-ray detection. A number of level lifetimes were determined for the first time with the Doppler-shift attenuation method and the low-lying excited states were characterized. From this new spectroscopic information, the third excited state, a ${0}^{+}$ level which had only been observed in a previous inelastic neutron scattering study, was verified. Reduced transition probabilities were calculated; comparisons were drawn with a vibrational description of the nucleus and found lacking. The ${3}^{\ensuremath{-}}$ octupole phonon has been confirmed, and the complete negative-parity multiplet resulting from the $\ensuremath{\nu}(1{h}_{11/2}2{d}_{3/2})$ configuration has also been tentatively identified for the first time in the $N=80$ isotones.

The results of a neutron inelastic scattering experiment performed at the Geel Electron Linear Accelerator pulsed white neutron source of the European Commission Joint Research Centre are reported. The neutrons with energies up to 18 MeV interacted with a $^{\mathrm{nat}}\mathrm{Ti}$ sample and the $\ensuremath{\gamma}$ rays resulting from inelastic scattering reactions on the stable isotopes were detected using the Gamma Array for Inelastic Neutron Scattering (GAINS) spectrometer. We were able to measure the $\ensuremath{\gamma}$-production cross sections for 21 transitions in the five stable Ti isotopes. From these, the level cross sections and the total inelastic cross sections were determined. Our experimental results are compared with theoretical calculations performed using the talys 1.8 code, evaluated nuclear data libraries, and also with previously reported results.

A novel method is presented to determine the optical scattering length in scintillator crystals by directly measuring the scattered light power. It enables to eliminate the large uncertainties in deriving scattering lengths from the measured transmittivity using literature data for the index of refraction ("indirect measurement"). Using the new method, we distinguish the fluorescent and non-fluorescent part of the optical response of the LYSO scintillators that are widely used in PET detectors. Below 420 nm the scattered intensity mainly stems from fluorescence while above this wavelength it is due to elastic or inelastic scattering. The latter is strongly dependent on the crystals' defect properties. Scattering lengths at 405 nm are in the range of 1 to 2 m and vary from sample to sample even from the same vendor. In the non-fluorescent regime, Rayleigh scattering of the studied sample measured at 532 nm shows strong orientation dependence. The average scattering length determined by the direct method is 29 +/- 3 m (as compared to 0.02 to 0.5 m derived from indirect measurement), i.e. orders of magnitude larger than the typical crystal dimensions. Therefore, in contrast to the widespread belief in the literature, scattering in LYSO crystal scintillators has potentially negligible effect on the operation of PET systems, at least in the non-fluorescent regime.

Neutron scattering measurements have played important roles in not only the structural information study, but also the dynamical insight of solid state ionic materials in the form of polymer, crystalline and glassy materials. Quasielastic neutron scattering (QENS) measurement explores the diffusion mechanism of mobile ions, on the other hand, inelastic neutron scattering (INS) reveals the dynamical insight of solid ionic conductor materials. Here we present the neutron scattering study of superionic glass (LiI)0.3(LiPO3)0.7 by using the inelastic neutron spectrometer AMATERAS at the Japan Proton Accelerator Research Complex (J-PARC). Simultaneous two dimensional maps of dynamical structure factor S(Q,E) with the incident energy Ei 93.85, 23.59, 10.57 and 5.92 meV over a wide momentum transfer (Q)-range were observed for (LiI)0.3(LiPO3)0.7. The first sharp diffraction peak appears at Q ~ 1.8 A− 1 in the elastic structure factor. From the inelastic scattering, low energy excitation or the Boson Peak appears at ~ 6.0–7.0 meV. The extra quasielastic scattering was observed in the energy range 1 meV

An experiment on small-angle polarized-neutron diffraction by a two-dimensional spatially ordered array of nickel nanowires embedded in a porous anodic alumina matrix is discussed. The contributions of nonmagnetic (nuclear) structures and nuclear magnetic interference indicating the correlation between magnetic and nuclear structures are discussed. Magnetic scattering is two orders of magnitude smaller than nuclear scattering and, hence, turns out to be weakly distinguishable. The ordered magnetic composite nanostructure of a sample leads to strong interaction between the neutron wave and the structure itself, which, in turn, implies a twofold (miltiple scattering) nuclear scattering process. Nuclear magnetic interference scattering must be analyzed allowing for twofold scattering conditions, which substantially distorts the intensity distribution of the interference contribution of first-order diffraction peaks.