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Neutron depolarization experiments have shown that the intragranular magnetic domain structure of polycrystalline ferrites exhibits a marked grain size dependence. Below a grain size of around $3~\mu \text{m}$ , the magnetic domain structure changes from the two-domain to the mono-domain state. Ferrites composed of mono-domain grains exhibit low dissipation at megahertz frequencies. This is attributed to the absence of intragranular domain wall movement, i.e., a microscopic origin for dissipation in ferrites has been identified. The implications of this clear observation and evidence for a transition from the mono- to two-domain state in ferrites for micromagnetic theory when a single particle becomes monodomain, as well as for the initial permeability mechanisms in polycrystalline ferrites, are discussed. [ABSTRACT FROM AUTHOR]

Fracture structures are important natural gas transport spaces in shale gas reservoirs, and their storage state in shale gas reservoirs seriously affects gas production and extraction efficiency. This work uses numerical modeling techniques to investigate the logging response law of the thermal and epithermal neutrons in the gas-containing fracture environment at various angles, applying neutron logging as a technical method. To increase the precision of the evaluation of the natural gas storage condition in shale gas reservoirs, the angle of the fractures' neutron logging data is analyzed. It is found that even in an environment with the same porosity of the fractures, there are significant differences in the logging results due to the different angles of the fracture alignment: 1. the neutron counts in the high-angle (70–90°) fracture environment are 2.25 times higher than in the low-angle (0–20°), but the diffusion area of the neutrons is only 10.58% of that in the low-angle (0–20°); 2. in the neutron energy spectrum, neutron counts are spreading to the high-energy region (7–13 MeV) along with the increase in the angle of the fracture, and the feature is especially prominent in the approximately vertical (60–90°) fracture environment, which is an increase of 528.12% in comparison with the counts in the approximately horizontal angle (0–30°) environment. The main reason for these differences is the variation in the volume of the fracture within the source radiation. This volumetric difference results from the variation in fracture angles (even though the fracture porosity is the same). In view of the above phenomenon, this paper proposes the concept of "effective fracture volume", which can intuitively reflect the degree of influence of fracture angle on neutron logging results. Further, based on the unique characteristics of shale gas reservoirs and neutrons, this paper provides important theoretical support for the modification of the porosity of the field operation, the evaluation of the physical characteristics of the gas endowment space, and the assessment. [ABSTRACT FROM AUTHOR]

Understanding the behaviour of a neutron spectrum with burnup is important for describing various phenomena associated with reactor operation. The quest to understand the neutron spectrum comes with a lot of questions. One question that is usually asked by students is: Does the neutron spectrum harden or soften with burnup? Most textbooks used by students do not provide a definite answer to this question. This paper seeks to answer this question using a 3D model of a standard 17 × 17 pressurised water reactor fuel assembly. Two cases were studied using the Serpent Monte Carlo code: the first considered the fuel assembly with constant boron concentration (traditionally found in many published papers), and the second considered boron iteration (where the boron concentration was reduced with burnup). Neutron spectra for the two cases at beginning of life and end of life were compared for spectral shifts. In addition, thermal spectral indices were used to assess spectrum hardening or softening with burnup. Spectral shifts to lower energies were observed in the thermal region of the neutron spectrum, whereas the fast region experienced no spectral shift. There was an increase in thermal spectral indices indicating that the spectrum became soft with burnup. [ABSTRACT FROM AUTHOR]

We discuss the quantum-bouncer experiment involving ultracold neutrons in a braneworld scenario. Extra-dimensional theories typically predict the strengthening of gravitational interactions over short distances. In this paper, we specifically study the anomalous gravitational interaction between the bouncing neutron and the reflecting mirror, resulting from hidden dimensions, and investigate the effects of this new interaction on the outcome of the quantum-bouncer experiment in the context of a thick brane model. This analysis allows us to identify which physical quantity of the extra-dimensional theory this neutron experiment is capable of constraining. Based on the experimental data, we found a new and independent empirical bound on the free parameters of the model: the higher-dimensional gravitational constant and a parameter related to a transverse width of the confined matter inside the thickbrane. This new bound is valid in scenarios with an arbitrary number of extra dimensions greater than two. In this manner, by considering the thickness of the brane, we have been able to extend previous studies on this topic, which were limited to models with few codimensions, due to non-computability problems of power-law corrections of the gravitational potential. [ABSTRACT FROM AUTHOR]

This paper considers secondary neutrons contribution to the yield of 99mTc obtained from the thick Mo-sample via (p,2n) nuclear reaction channel. The physical yield was determined experimentally using 11-MeV cyclotron Eclipse RD with application of the new target assembly developed for solid sample irradiations and appeared to be 30.9 ± 1.3 MBq/μAh. The neutron flux over the sample was analyzed by MCNP simulations taking into account the construction elements of the target module and cyclotron self-shielding. The contribution to the 99mTc yield by indirect production via 98Mo(n,γ)99Mo → 99mTc reactions was estimated. [ABSTRACT FROM AUTHOR]

We present the first machine learning-based autonomous hyperspectral neutron computed tomography experiment performed at the Spallation Neutron Source. Hyperspectral neutron computed tomography allows the characterization of samples by enabling the reconstruction of crystallographic information and elemental/isotopic composition of objects relevant to materials science. High quality reconstructions using traditional algorithms such as the filtered back projection require a high signal-to-noise ratio across a wide wavelength range combined with a large number of projections. This results in scan times of several days to acquire hundreds of hyperspectral projections, during which end users have minimal feedback. To address these challenges, a golden ratio scanning protocol combined with model-based image reconstruction algorithms have been proposed. This novel approach enables high quality real-time reconstructions from streaming experimental data, thus providing feedback to users, while requiring fewer yet a fixed number of projections compared to the filtered back projection method. In this paper, we propose a novel machine learning criterion that can terminate a streaming neutron tomography scan once sufficient information is obtained based on the current set of measurements. Our decision criterion uses a quality score which combines a reference-free image quality metric computed using a pre-trained deep neural network with a metric that measures differences between consecutive reconstructions. The results show that our method can reduce the measurement time by approximately a factor of five compared to a baseline method based on filtered back projection for the samples we studied while automatically terminating the scans. [ABSTRACT FROM AUTHOR]

The asteroid impacts can be devastating for the life on the Earth. Thus, mitigation of this unwanted event is of crucial importance, and nuclear devices are state-of-the-art choice. The presented paper focuses on nuclear data validation of silicon and oxygen. Nuclear data validation is an essential task because nuclear data are the deciding factor for energy deposition profiles, which serve as input for subsequent hydrodynamic simulation, thus directly affecting the description of asteroid deflection. The silicon and oxygen in the form of silicate materials are abundant in asteroids. The set of neutron and gamma transport experiments using a primary neutron standard 252Cf neutron source was performed. The fast neutron spectrum in the energy range of 2–10 MeV was measured using a stilbene detector. The best agreement for fast neutron leakage spectra was reached using INDEN evaluation for 28Si and ENDF/B-VIII.0 16O evaluation. Activation foils sensitive in different energy ranges were utilized. The results depend on the examined reaction and distance from the source. Finally, the prompt gamma rays from capture and inelastic scattering were measured by an HPGe detector. With the exception of 28Si(n,n′) 1779 keV peak, other prompt gamma production peaks show significant discrepancies. The calculations for comparisons of different transport libraries were performed using Monte Carlo MCNP6.2 code. The results show the necessity of further improvement of evaluations for oxygen and silicon. • Energy deposition profile highly depends on used transport library. • Effect of different transport libraries on calculations. • Measurement of leakage neutron spectra from sand cylinder • Measurement of reaction rates of activated materials. • Measurement of prompt gammas. [ABSTRACT FROM AUTHOR]

In this paper, we present our QCD analysis of the Nucleon Form Factors presented by JLab to extract a new parameterization for the valence Generalized Parton Distributions (GPDs), H v q (x , ξ = 0 , t) and E v q (x , ξ = 0 , t). We choose simple parameterizations for x − and t − dependence of GPDs at zero skewness. These free parameters of the model are then obtained using old and new data of nucleon's elastic electromagnetic form factors (FFs) from JLAB. We have also used the "Hessian method" to perform a careful estimation of the uncertainties for the nucleon GPDs and corresponding observables originate from experimental errors. We also calculate the parton distribution functions (PDFs) in Impact parameter space to show the 3D structure of the Nucleon. We also calculated the proton and the neutron charge densities ρ ch (p , n) . We show that there is a highly localized negative charge near the center of the neutron and it is because of the negatively charged down quarks dominating the high momentum quarks in the neutron. Finally using the obtained Dirac's FF, we had an estimation for the proton charge radius. The predictions based on the obtained nucleon GPDs are in good agreement with all available experimental data and other phenomenological models. [ABSTRACT FROM AUTHOR]

In this paper, we get the nuclear mass-density parameter of known mass and known charge radius by using the AME2020 nuclear mass database and the CR2013 nuclear charge radius database. For the nuclei with N ≥ 2 1 , we obtained an empirical formula of the constant parameter equal to 0 for the difference of nuclear mass-density parameter between two neighboring isotope. That is, the nuclear mass-density parameter of the two neighboring isotopes was equal. By using this empirical formula combined with AME2020 and CR2013 databases, the calculated value of 625 nuclear charge radii was obtained. The root-mean-square deviation (RMSD) of nuclear charge radius that we have successfully obtained is σ = 0. 0 1 1 fm. In addition, one of the corrections is the neutron factor. This correction is the key improvement which reduces the RMSD to 0.0077 fm. Considering the neutron shell effect, the different shell ranges were divided into two categories for correction, and the RMSD was reduced to 0.0056 fm. Based on the revised empirical formula combined with the AME2020 database, the calculated and predicted values of nuclear charge radius were obtained with high accuracy. Some of these predictions are also very consistent with experimental values measured in recent years. In addition, we use BP neural network to study the difference of nuclear mass-density parameter on the basis of two categories. The RMSDs obtained are 0.0028 fm and 0.0038 fm, respectively. It can be seen that such a division has a certain degree of reliability and feasibility. These results show that the new relation proposed in this paper has simplicity and reliability, which can be compared with other local nuclear charge radius relations. [ABSTRACT FROM AUTHOR]

This document is a correction notice for a published paper titled "Tritium Desorption Behavior and Microstructure Evolution of Beryllium Irradiated at Low Temperature Up to High Neutron Dose in BR2 Reactor." The authors have made several corrections to the figures, tables, and text in the paper. The changes include removing and adding figures, correcting correlations, clarifying the tritium content in irradiated beryllium, and updating the data availability statement. The authors state that these corrections do not affect the scientific conclusions of the paper. [Extracted from the article]

VERA benchmark cases have been introduced by ORNL and detailed guidelines have been provided including the burnup chain data for a depletion analysis. The purpose of this paper was to analyze the performance of MCNP Monte Carlo code using VERA benchmark cases. Research on the VERA benchmark cases become important because its results will be useful for designing SMRs planned in the country. The VERA 2B and VERA 2P were selected as a representation for a typical fuel assembly of LWR configurations. The kinf MCNP calculations show a good agreement with the MCS and STREAM predictions at the Beginning of Cycle (BOC), Middle (MOC), and End (EOC). The kinf value at BOC calculated using MCNP for VERA 2B case shows a good agreement compared to KENO, Serpent, and OpenMC with a difference of less than 60 pcm while for VERA 2P case with a difference of less than 90 pcm. Doppler Temperature of reactivity Coefficient (DTC) and Moderator Temperature (MTC) results were negative and both became more negative as fuel burnup increased. The βe f f values of both cases were close to 670 pcm during BOC since both cases use 235U fissile nuclear material. The 239Pu production in VERA 2B was higher than 2P since higher 238U in 2B and 24 pins of mixed lower enrichment and gadolinium in 2P lowers its heavy metal loading followed by the neutron spectrum shifting. It can be concluded that these results can be used in the development of computational performance for overall core analysis to strengthen the basic design of the SMR to be built in Indonesia. [ABSTRACT FROM AUTHOR]

In response to the significant dependency on empirical judgment in measuring the prompt neutron decay constant with the traditional Rossi-alpha method and the issue of requiring an excessive number of detectors with the DMD-Rossi-alpha method, this paper introduces a calculation method for the prompt neutron decay constant based on a combination of Latin Hypercube Sampling (LHS), Dynamic Mode Decomposition (DMD), and the Rossi-alpha method. Initially, the method uses LHS to expand the sample dataset of neutron noise data to reduce the number of detectors required. It then employs the Rossi-alpha method to construct a Rossi-alpha distribution model from neutron noise data. Finally, it utilizes DMD for feature extraction from the Rossi-alpha distribution model, thereby determining the prompt neutron decay constant. Research findings demonstrate that, by simulating the KUCA facility using RMC3.5 in a near-critical state, the relative error of the α value calculated by the LHS-DMD-Rossi-alpha method model is 9% less than that calculated by the Rossi-alpha method. This approach, capable of enhancing the precision of measuring the prompt neutron decay constant with just a single detector, holds significant theoretical value and engineering significance for the advancement of reactor physics and experimental techniques. [ABSTRACT FROM AUTHOR]

With neutron diffraction, the local stress and texture of metallic components can be analyzed non-destructively. For both, highly accurate positioning of the sample is essential, requiring the measurement at the same sample location from different directions. Current sample-positioning systems in neutron diffraction instruments combine XYZ tables and Eulerian cradles to enable the accurate six-degree-of-freedom (6DoF) handling of samples. However, these systems are not flexible enough. The choice of the rotation center and their range of motion are limited. Industrial six-axis robots have the necessary flexibility, but they lack the required absolute accuracy. This paper proposes a visual servoing system consisting of an industrial six-axis robot enhanced with a high-precision multi-camera tracking system. Its goal is to achieve an absolute positioning accuracy of better than 50 μ m. A digital twin integrates various data sources from the instrument and the sample in order to enable a fully automatic measurement procedure. This system is also highly relevant for other kinds of processes that require the accurate and flexible handling of objects and tools, e.g., robotic surgery or industrial printing on 3D surfaces. [ABSTRACT FROM AUTHOR]

Large-scale underground hydrogen storage can replace fossil fuel power generation and balance long-term and short-term energy consumption. There is still a lack of research on the quantitative evaluation of hydrogen saturation in hydrogen storage formations. By constructing a sandstone hydrogen storage reservoir model for numerical simulation of gas-water identification, a method for qualitative and quantitative evaluation of hydrogen saturation and hydrogen density in reservoirs is found. Monitor the change of hydrogen saturation in the reservoir, master the storage status of hydrogen, and enrich the hydrogen injection plan. In this paper, the RPM-formation model is established by combining the pulse neutron logging technology and the Monte Carlo method. The relationship between the capture gamma count ratio the hydrogen density and the hydrogen saturation under different porosity conditions is simulated. The effect of formation water salinity and shale content on the relationship between the count ratio and porosity. The results show that under the same porosity condition, the counting ratio increases with the increase of hydrogen density, and increases or decreases with the increase of hydrogen saturation under different hydrogen densities. The salinity and shale content of the formation water affect the count ratio. Based on the simulation data, the evaluation model of hydrogen saturation is established, the influence of shale content and formation water salinity is analyzed and corrected, the capture gamma ratio chart is constructed, and the method of qualitative and quantitative evaluation of the reservoir is found, which provides a logging method for monitoring the change of hydrogen saturation in different components of underground hydrogen storage formation. [Display omitted] • The simulation process of pulsed neutron logging is realized by Monte Carlo method. • The qualitative evaluation of reservoir gas-bearing property is realized by using Rcapture. • An evaluated model was established to quantify reservoir hydrogen saturation. • A correction chart corrects shale content and formation water salinity. • The research results can assist in optimizing the hydrogen injection scheme. [ABSTRACT FROM AUTHOR]

In this paper, the Penning ion sources (PIS) characteristics are studied applied to their use in an inertial electrostatic confinement (IEC) system based on a two-electrode spherical chamber. In the IEC chamber with deuterium filling, due to multiple oscillations of ion beams through a gas-plasma target inside the central electrode, a beam-target mechanism for generating neutron radiation is realized. Based on the method for the neutron yield calculating of IEC systems, the requirements for a PIS are formulated to ensure the neutron yield (2.5 MeV) in the range of 106–107 neutr./s. A computational and experimental study of the discharge combustion regimes in the PIS has been carried out depending on the configuration of the external magnetic field and comparison of the currents in the PIS and the currents through the central electrode of the IEC chamber in the pressure range from 0.1 to 10 mTorr. The optimal number of PIS in the considered spherical chamber of the IEC justified. [ABSTRACT FROM AUTHOR]

Neutron star–white dwarf (NSWD) binaries are one of the most abundant sources of gravitational waves (GWs) in the Milky Way. These GW sources are the evolutionary products of primordial binaries that experienced many processes of binary interaction. We employ a binary population synthesis method to investigate the properties of Galactic NSWD binaries detectable by the Laser Interferometer Space Antenna (LISA). In this paper, only the NSWD systems with a COWD or ONeWD component are included. We consider various models related to mass-transfer efficiencies during primordial binary evolution, supernova explosion mechanisms at NS formation, common envelope ejection efficiencies, and critical WD masses that determine the stability of mass transfer between WDs and NSs. Based on our calculations, we estimate that tens to hundreds of LISA NSWD binaries exist in the Milky Way. We find that the detection of LISA NSWD binaries is able to provide profound insights into mass-transfer efficiencies during the evolution of primordial binaries and critical WD masses during mass transfer from a WD to an NS. [ABSTRACT FROM AUTHOR]

The development of higher-order method of characteristics (MOC) discretizations has become of great interest to improve the performance of solvers based on the standard Stepwise Constant (SC) MOC approximation. Many codes nowadays implement a Stepwise Linear (SL) volume flux approximation or diamond differencing schemes. In the multigroup lattice solver TDT of the industrial code APOLLO3®, developed at CEA, a Linear Surface (LS) scheme was implemented. In this method, the flux is reconstructed from a linear interpolation made from surface values, therefore ensuring a similar spatial linear development but with a lower computational cost than the volume-based approximations. However, the LS-MOC scheme can conserve only the constant spatial moment of the flux. To overcome this limitation, in this paper we propose an improved version of the LS scheme called LS- $$xy$$ xy able to preserve the linear spatial moments of the flux. Compared to the other high-order volume-based approximations, the LS- $$xy$$ xy scheme also preserves flux surface moments, which guarantees higher accuracy. Moreover, our scheme has a lower memory footprint because it does not require the storage of response matrices that are dependent on region, group, and anisotropy order. Tests carried out on severe rodded assembly cases show the superior performance of the proposed method with respect to not only the classic SC or LS MOC scheme but also the SL scheme. [ABSTRACT FROM AUTHOR]

This paper presents a study of both the elastic and inelastic scattering of a deuteron beam on 13 C at laboratory energy of 18 MeV. The first 10 excited states of the carbon isotope were studied in terms of single-particle and collective models of excitation. Experimental cross sections were obtained by the well-known Δ E–E method. Elastic scattering data were analyzed using an optical model including a nucleus–nucleus interaction potential, while inelastic scattering data were processed using the coupled-channels approach. For the single-particle model, the spectroscopic amplitudes were obtained through calculations of the large-scale shell model with the YSOXT effective NN-potential. A double folding potential was obtained for the d + 13 C system. A comparison of model calculations with the experimental cross sections was demonstrated. The extracted deformation parameters and calculated spectroscopic information are shown in tables. The ability of the collective model to describe all excited states was demonstrated by good agreement when comparing the calculated cross sections in the collective model and experimental data. The single-particle model turned out to be significant only for the excited state of 3.09 MeV. The dominant role in the formation of the corresponding cross section is played by the 12 C ground state core with the 2 S 1 / 2 neutron. [ABSTRACT FROM AUTHOR]

The isotopic shifts of 149Sm–150Sm and 157Gd–158Gd have often been observed in meteorites and lunar surface materials, because they result from the neutron-capture reactions associated with secondary neutrons produced by cosmic-ray irradiation. While the Sm and Gd isotopic shifts can mainly be used for the estimation of thermal neutron fluences that of 167Er–168Er has recently been applied in the estimation of epithermal neutron fluences. The systematic isotopic dataset of Sm, Gd and Er helps us to consider the details of planetary materials' cosmic-ray exposure conditions using the balance of the fluences between thermal and epithermal neutrons. This paper reviews a series of isotopic variations of Sm, Gd, and Er in association with neutron-capture reactions for the application of planetary sciences. As a new attempt and possibility for better understanding the neutron fluence and its energy distribution, the use of Yb isotopic variation is then discussed using two different data sources, namely lunar regolith and the Oklo natural reactors. Finally, the preliminary result for the precise isotopic measurement of Yb is presented from the viewpoint of chemical separation and instrumental improvement. [ABSTRACT FROM AUTHOR]

In this paper, an overview of wide-bandgap (WBG) semiconductors for radiation detection applications is given. The recent advancements in the fabrication of high-quality wafers have enabled remarkable WBG semiconductor device applications. The most common 4H-SiC, GaN, and β-Ga2O3 devices used for radiation detection are described. The 4H-SiC and GaN devices have already achieved exceptional results in the detection of alpha particles and neutrons, thermal neutrons in particular. While β-Ga2O3 devices have not yet reached the same level of technological maturity (compared to 4H-SiC and GaN), their current achievements for X-ray detection indicate great potential and promising prospects for future applications. [ABSTRACT FROM AUTHOR]

[Display omitted] The scientific paper presents studies of the radiation-protective features of a polymer composite material for protection against space radiation based on poly-tetra-fluoro-ethylene, Bi 2 O 3 bismuth oxide, WC tungsten carbide, B 4 C boron carbide, TiH 1.7 titanium hydride shot. The composite provides for a high degree of protection against ionizing radiation, including protection against exposure to secondary neutrons: macroscopic fast neutrons removal cross-section (E > 2 MeV) 0.1331–0.1414 cm−1, thermal-velocity neutrons removal cross-section (E < 0.4 eV), cm−1 0.1183–0.1257 cm−1. A shield made of the tailored composition of the proposed 6 cm thick polymer composite attenuates the intensity of neutron radiation by more than 50 % at energies from 0.1 to 5 MeV, in particular, the greatest attenuation of the neutron radiation intensity occurs at an energy of 0.1 MeV with a sharp increase in attenuation when passing through a 2 cm thick shield and complete absorption occurs passing through a 6 cm thick shield. This material can be used to protect astronauts and radio-electronic equipment from the effects of adverse or harmful space factors, including exposure to secondary neutrons, and this material can also be used to protect crews of ships with mobile nuclear reactors such as atomic submarines and nuclear-powered icebreakers. [ABSTRACT FROM AUTHOR]

This paper present the impact on hardness assurance testing and the enhanced degradation of proton and neutron of the semiconductor device. In this work, it is shown that protons and neutrons can induce enhanced degradation in both trench and planar geometry power MOSFETs. Specifically, large shifts in current-voltage characteristics of some devices were observed at extremely low proton total dose levels (as low as 2 rad(SiO2)). These shifts induced significant increases (more than three orders of magnitude) in device "off" state leakage current. Neutron irradiations show similar degradation at equivalent fluence levels, even though neutrons do not deposit dose due to direct ionization. In addition, this increase in leakage current occurs at a much lower total dose level than expected based on 60Co gamma ray data. These data therefore suggest that the mechanism responsible for the enhanced degradation is a microdose effect associated with secondary particles produced through nuclear interactions between protons and neutrons and the materials in integrated circuits. The secondary particles deposit enough charge in the gate oxide to induce a parasitic drain to source leakage path in the transistor. Although the results are demonstrated for only trench and planar geometry power MOSFETs, microdose effects can impact the radiation response of other integrated circuit types. [ABSTRACT FROM PUBLISHER]

This paper is a review of the present status of neutrino mass physics, which grew out of an APS sponsored study of neutrinos in 2004. After a discussion of the present knowledge of neutrino masses and mixing and some popular ways to probe the new physics implied by recent data, it summarizes what can be learned about neutrino interactions as well as the nature of new physics beyond the Standard Model from the various proposed neutrino experiments. The intriguing possibility that neutrino mass physics may be at the heart of our understanding of a long standing puzzle of cosmology, i.e. the origin of matter-antimatter asymmetry is also discussed. [ABSTRACT FROM AUTHOR]

Inline algorithms have been proposed for coupling Monte Carlo neutron transport solvers with several other physics, such as xenon and iodine densities and thermal hydraulics. This paper proposes a new inline algorithm that can be applied to burnup calculations. The algorithm is a modification of the predictor-corrector method, where the corrector-step nuclide densities are converged simultaneously with the fission source. This could, in principle, obviate the need for two full neutronics solutions per time-step while still allowing the accuracy of predictor-corrector methods with improved stability. This paper describes the algorithm and demonstrates its stability properties through a Fourier analysis. Although not unconditionally stable, judicious use of batching and relaxation are shown to greatly improve the algorithm's stability properties in realistic systems. [ABSTRACT FROM AUTHOR]

The paper reviews the recent progress in the description of isospin-symmetry breaking within the nuclear shell model and applications to actual problems related to the structure and decay of exotic neutron-deficient nuclei and nuclei along the N = Z line, where N is the neutron number and Z the atomic number. The review recalls the fundamentals of the isospin formalism for two-nucleon and many-nucleon systems, including quantum numbers, the spectrum's structure and selection rules for weak and electromagnetic transitions; and at the end, summarizes experimental signatures of isospin-symmetry breaking effects, which motivated efforts towards the creation of a relevant theoretical framework to describe those phenomena. The main approaches to construct accurate isospin-nonconserving Hamiltonians within the shell model are briefly described and recent advances in the description of the structure and (isospin-forbidden) decay modes of neutron-deficient nuclei are highlighted. The paper reviews major implications of the developed theoretical tools to (i) the fundamental interaction studies on nuclear decays and (ii) the estimation of the rates of nuclear reactions that are important for nuclear astrophysics. The shell model is shown to be one of the most suitable approaches to describing isospin-symmetry breaking in nuclear states at low energies. Further efforts in extending and refining the description to larger model spaces, and in developing first-principle theories to deal with isospin-symmetry breaking in many-nucleon systems, seem to be indispensable steps towards our better understanding of nuclear properties in the precision era. [ABSTRACT FROM AUTHOR]

Integral experiments covering neutron leakage from geometrically simple assemblies with a 252Cf source inside are very valuable tools usable in the validation of transport cross-section data since geometric uncertainties play a much smaller role in simple geometric assemblies than in complex assemblies as for example reactor pressure vessel geometry. Since 252Cf spontaneous fission is a standard neutron source, the uncertainties connected with the source neutron spectrum can be even neglected. The paper refers to validation efforts of neutron leakage from an ~50 × 50 × 50-cm stainless steel block in the Research Center Rez. Both the neutron leakage flux at a distance of 1 m from the center of the cubical assembly using stilbene spectrometry and activation rates at different positions of the assembly were evaluated. In addition to experiments, main sources of uncertainty were identified and evaluated. The results of the stilbene measurements are consistent with the activation measurement results. [ABSTRACT FROM AUTHOR]

The Second Target Station project at Oak Ridge National Laboratory will develop a cold neutron source to meet growing experimental needs. This paper describes calculations of the residual dose rates associated with the monolith shield plug and the beamline bunker, two key conventional operations and radiation safety features. While neutron production is active, the instrument hall outside the bunker must be generally accessible with dose rates of less than 0.25 mrem/h. When neutron production is halted, the bunker must be accessible for hands-on maintenance operations. These two requirements form the cause for the assessments reported herein of residual dose rates caused by the monolith shield plug and residual dose rates in the bunker. The monolith shield plug was shown to not produce significant dose rates inside the bunker after a 20-year lifetime, and the residual dose rates inside the bunker for the case of an operating beamline were shown to reasonably allow for hands-on maintenance. These calculations are based on preliminary design models of the relevant systems. Additionally, an example showing the significance of considering neutron supermirror physics in transport calculations that track nuclide production and destruction rates to produce gamma sources for residual dose rate calculations is included. The example shows that if neutron supermirror physics is not considered, dose rate fields may be significantly underpredicted. [ABSTRACT FROM AUTHOR]

At the U.S. Department of Energy's Oak Ridge National Laboratory, the Second Target Station (STS) beamline sources for preliminary design have been used to perform a shielding analysis of the bunker. Prompt total effective dose rates (i.e., neutron plus photon effective dose rates when the proton beam is on) were calculated on top of the bunker roof and outside the bunker wall. These areas outside the bunker will be generally accessible, so the prompt total dose rate in these areas should not exceed 2.5 μSv‧h−1 (0.25 mrem‧h−1). This paper presents the required shielding thicknesses to meet this dose rate limit. In one instance, this dose rate limit is not met: For a combination of populated and unpopulated beamlines, the prompt total dose rate outside the bunker across from the unpopulated beamline, which has less shielding because of the lack of beamline shielding, slightly exceeds 2.5 μSv‧h−1. Once more details are known regarding the STS high-density concrete density and composition, a future analysis will investigate the shielding modifications required to reduce the calculated prompt total dose rates for this configuration to less than 2.5 μSv‧h−1. [ABSTRACT FROM AUTHOR]

The European Spallation Source (ESS), presently under construction in Lund, Sweden, is a multidisciplinary international laboratory that, once completed at full specifications, will operate the world's most powerful pulsed neutron source. Supported by a 3 M Euro Research and Innovation Action within the European Union Horizon 2020 program, a design study (HighNESS) is now underway to develop a second neutron source located below the spallation target. Compared to the first source, which is located above the spallation target and designed for high cold and thermal brightness, the new source is being optimized to deliver higher intensity and a shift to longer wavelengths in the spectral regions of cold neutrons (CNs) (2 to 20 Å), very cold neutrons (VCNs) (10 to 120 Å), and ultracold neutrons (UCNs) ($ \gt {\kern 1pt}$ > 500 Å). The second source consists of a large liquid deuterium moderator to deliver CNs and serve secondary VCN and UCN sources, for which different options are under study. These new sources will boost several areas of condensed matter research and will provide unique opportunities in fundamental physics. The HighNESS project is now entering its last year, and we are working toward the Conceptual Design Report of the ESS upgrade. In this paper, results obtained in the first 2 years, ongoing developments, and future perspectives are described. [ABSTRACT FROM AUTHOR]

The paper presents the results of studies of additively manufactured metal samples using neutron imaging at the IR-8 research reactor of the National Research Center "Kurchatov Institute" (NRC KI). The advantages and disadvantages of neutron imaging using monochromatic (DRAGON station) and polychromatic (PONY tomograph) neutrons when studying internal structure of the samples are demonstrated. [ABSTRACT FROM AUTHOR]

In this paper, we consider the evolution of limited fission chains using the theory of branching processes for the development of a scientific and technical approach and methods of obtaining experimental data under laboratory conditions to verify models of neutron probabilistic processes in multiplying systems. [ABSTRACT FROM AUTHOR]

The paper presents the simulation of a complex of reserch with ultracold neutrons at the reactor PIK (Gatchina, Russia). The complex is being built on the basis of a high-intensity source of ultracold neutrons at the channel GEK-4. A Monte Carlo model has been developed, which includes a source, a neutron guide system and an experimental setup for search for the electric dipole moment of a neutron, taking into account their real location in the main hall of the reactor. Using the developed computer model the density of ultracold neutrons in the setup was obtained, which is 200 cm–3. It is 50 times higher than at the source at the Institut Laue-Langevin (Grenoble, France). This density will allow to achieve a sensitivity of measurements in the experiment of 1 × 10–27 electrons cm/year. [ABSTRACT FROM AUTHOR]

This paper reports on the development of stable tumor-specific gold nanoparticles (AuNPs) activated by neutron irradiation as a therapeutic option for the treatment of cancer with high tumor angiogenesis. The AuNPs were designed with different mono- or dithiol-ligands and decorated with different amounts of Arg-Gly-Asp (RGD) peptides as a tumor-targeting vector for αvβ3 integrin, which is overexpressed in tissues with high tumor angiogenesis. The AuNPs were evaluated for avidity in vitro and showed favorable properties with respect to tumor cell accumulation. Furthermore, the therapeutic properties of the [198Au]AuNPs were evaluated in vitro on U87MG cells in terms of cell survival, suggesting that these [198Au]AuNPs are a useful basis for future therapeutic concepts. [ABSTRACT FROM AUTHOR]

In this paper, a regression model between neutron star crust–core pressure and the symmetry energy characteristics was estimated using the Akaike information criterion and the adjusted coefficient of determination R a d j 2 . The most probable value of the transition density, which should characterize the crust–core environment of the sought physical neutron star model, was determined based on the obtained regression function. An anti-correlation was found between this transition density and the main characteristic of the symmetry energy, i.e., its slope L. [ABSTRACT FROM AUTHOR]

The main task in creating high-current cables based on HTSC-2 wires for thermonuclear installations is to maximize the resistance of the cable to mechanical stresses. Its solution is directly related to the strength of the HTSC-2 wires, which is determined by the supporting steel tape substrate. Therefore, the diagnosis of stresses in the carrier tape is of particular importance. The only direct method for measuring internal strains and residual stresses inside a material is neutron stress diffractometry. However, its application to thin steel tapes is limited by the intensity of the neutron beam. In this study, by the example of a 100-µm-thick AISI 310S stainless steel tape applied as a substrate in manufacturing HTSC-2 wire at the National Research Center Kurchatov Institute, it is shown that this restriction can be circumvented if the measurements are carried out on stacks of tapes similar to HTSC stacks in high-current cables. In this approach, the diagnosis with neutron stress diffractometry is performed on the AISI 310S tape as delivered, after mechanical polishing, and after applying a YSZ buffer layer. The high sensitivity of the method is noted, which makes it possible to determine the crescent-shaped deformation of the tape and the degree of its stretching after mechanical polishing and to measure the residual stresses arising during the deposition of the YSZ layer. The results obtained show that the neutron stress diffractometry has good prospects for diagnosing internal strains and stresses in HTSC stacks of high-current cables. [ABSTRACT FROM AUTHOR]

This paper describes a method for calculating the neutron yield for inertial electrostatic confinement systems that is based on the beam-target mechanism of neutron production. Specific features of inertial electrostatic confinement systems are addressed, and their consistent description and consideration for the relationship between the above features and the current and concentration and velocity of ions involved in the interaction allowed developing an approach to describe neutron generation processes in such systems. Comparison of the calculation with experimental data shows satisfactory agreement; the deviation does not exceed 40%. [ABSTRACT FROM AUTHOR]