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Fast neutron absorption spectroscopy is widely used in the study of nuclear structure and element analysis. However, due to the traditional neutron source pulse duration being of the order of nanoseconds, it is difficult to obtain a high-resolution absorption spectrum. Thus, we present a method of ultrahigh energy-resolution absorption spectroscopy via a high repetition rate, picosecond duration pulsed neutron source driven by a terawatt laser. The technology of single neutron count is used, which results in easily distinguishing the width of approximately 20 keV at 2 MeV and an asymmetric shape of the neutron absorption peak. The absorption spectroscopy based on a laser neutron source has one order of magnitude higher energy-resolution power than the state-of-the-art traditional neutron sources, which could be of benefit for precisely measuring nuclear structure data.

The absorption grating is a critical component of neutron phase contrast imaging technology, and its quality directly influences the sensitivity of the imaging system. Gadolinium (Gd) is a preferred neutron absorption material due to its high absorption coefficient, but its use in micro-nanofabrication poses significant challenges. In this study, we employed the particle filling method to fabricate neutron absorption gratings, and a pressurized filling method was introduced to enhance the filling rate. The filling rate was determined by the pressure on the surface of the particles, and the results demonstrate that the pressurized filling method can significantly increase the filling rate. Meanwhile, we investigated the effects of different pressures, groove widths, and Young’s modulus of the material on the particle filling rate through simulations. The results indicate that higher pressure and wider grating grooves lead to a significant increase in particle filling rate, and the pressurized filling method can be utilized to fabricate large-size grating and produce uniformly filled absorption gratings. To further improve the efficiency of the pressurized filling method, we proposed a process optimization approach, resulting in a significant improvement in the fabrication efficiency.

Gamma-rays and fast and thermal neutron attenuation features of (Bi2O3)x–(TeO2)(100−x) (where x = 5, 8, 10, 12, and 15 mol%) and [(TeO2)0.7–(B2O3)0.3](1−x)–(Bi2O3)x (where x = 0.05, 0.10, 0,15, 0.20, 0.25, and 0.3 mol%) glass systems have been explored and compared. For all samples, mass attenuation coefficients (μ/ρ) are estimated within 0.015–15 MeV photon energy range by MCNP5 simulation code and correlated with WinXCom results, which showed a satisfactory agreement between computed μ/ρ values by these both methods. Additionally, effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), total atomic cross-section (σa), and total electronic cross-section (σe) are calculated by utilizing μ/ρ values. The μ/ρ, Zeff, and Neff are energy dependent and have higher values at the lowest energy and smaller values at higher energies. Moreover, using the G–P fitting method as a function of penetration depth (up to 40 mfp) and incident photon energy (0.015–15 MeV range), exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) are evaluated. Both 85TeO2–15Bi2O3 (mol%) and 49TeO2–21B2O3–30Bi2O3 (mol%) samples, by possessing higher values of Zeff, exhibit minimum EBF and EABF values. Highest μ/ρ, Zeff values and lowest HVL, TVL, MFP values of 49TeO2–21B2O3–30Bi2O3 (mol%) sample indicated its better gamma-ray absorption capability among all selected glasses. Further, macroscopic effective removal cross-section for fast neutrons (ΣR), coherent scattering cross-section (σcs), incoherent scattering cross-section (σics), absorption cross-section (σA), and total cross-section (σT) values for thermal neutron attenuation have been computed. Among all samples, 49TeO2–21B2O3–30Bi2O3 (mol%) glass possesses a better ΣR value for fast neutron attenuation, while the largest ‘σT’ value of 66.5TeO2–28.5B2O3–5Bi2O3 (mol%) sample suggests its good thermal neutron absorption efficiency.

In this paper, the mechanism of neutron absorption and common reinforced particles is introduced, and recent research progress on different types of neutron-shielding materials (borated stainless steels, B/Al Alloy, B4C/Al composites, polymer-based composites, and shielding concrete) for transportation and wet or dry storage of spent fuel is elaborated, and critical performance is summarized and compared. In particular, the most widely studied and used borated stainless steel and B4C/Al composite neutron-absorption materials in the field of spent fuel are discussed at length. The problems and solutions in the preparation and application of different types of neutron-shielding materials for spent fuel transportation and storage are discussed, and their research priorities and development trends are proposed.

The effect of Bi 2 O 3 content on photon, alpha particle, proton, fast and thermal neutron shielding capacity, and elastic moduli of 10ZnO-(90-x)B 2 O 3 -xBi 2 O 3 (ZBB-glasses): x = 25–50 mol% has been investigated. The mass density and Bi-content of the ZBB-glasses had the greatest impact on the values of mass and linear attenuation coefficients. The mass and linear attenuation coefficients values were followed the trend (ZBB25) MAC,LAC  < (ZBB30) MAC,LAC  < (ZBB35) MAC,LAC  < (ZBB40) MAC,LAC  < (ZBB45) MAC,LAC  < (ZBB50) MAC,LAC . The mean free path (MFP) and half value layer (HVL) were having the same trend and opposite to which obtained in mass and linear attenuation coefficients. All the ZBB-glasses showed almost similar charged particle shielding capacity. However, ZBB50 had a comparable charged particle absorption efficiency. There was a 57% growth in fast neutron removal cross section as Bi 2 O 3 molar concentration increased to 50% in the ZBB-glass matrix. ZBB50 possesses the highest fast neutron removal cross section among the ZBB-glasses. In terms of thermal neutron absorbing capacity, the presence of B in the glass matrix ensures that the ZBB-glasses are good thermal neutron absorption. ZBB25 has the highest thermal neutron absorption capacity among the investigated glasses. Generally, ZBB-glasses can be adopted for photon, thermal neutron, proton, and alpha particle shielding purposes. In addition, elastic (shear, longitudinal, and Young’s) moduli and Poisson’s ratio are changed significantly with the increase of Bi 2 O 3 content mol% in ZBB-glasses.

Sensitive and fast detection of neutrons and gamma rays is vital for homeland security, high‐energy physics, and proton therapy. Fast‐neutron detectors rely on light organic scintillators, and γ‐ray detectors use heavy inorganic scintillators and semiconductors. Efficient mixed‐field detection using a single material is highly challenging due to their contradictory requirements. Here we report hybrid perovskites (C8H12N)2Pb(Br1−xClx)4 that combine light organic cations and heavy inorganic skeletons at a molecular level to achieve unprecedented performance for mixed‐field radiation detection. High neutron absorption due to a high density of hydrogen, strong radiative recombination within the highly confined [PbX6]4− layer, and sub‐nanometer distance between absorption sites and radiative centers, enable a light yield of 41 000 photons/MeV, detection pulse width of 2.97 ns and extraordinary linearity response toward both fast neutrons and γ‐rays, outperforming commonly used fast‐neutron scintillators. Neutron energy spectrum, time‐of‐flight based fast‐neutron/γ‐ray discrimination and neutron yield monitoring were all successfully achieved using (C8H12N)2Pb(Br0.95Cl0.05)4 detectors. We further demonstrate the monitoring of reaction kinetics and total power of a nuclear fusion reaction. We envision that molecular hybridized scintillators open a new avenue for mixed‐field radiation detection and imaging. New hybrid perovskite scintillator that combine light organic cations and heavy inorganic skeletons at a molecular level was proposed for fast‐neutron/γ‐ray mixed‐field detection. By utilizing its advantages of hydrogen enrichment, high equivalent atomic number, strong radiative recombination within the highly confined [PbX6]4‐layer, and sub‐nanometer distance between absorption sites and radiative centers, the effective discrimination of pulsed fast neutron and γ signals was realized based on time‐of‐flight technology, so as to obtain the time information and energy information of the nuclear reaction process accurately.

Boron nitride nanotubes (BNNTs) are emerging nanomaterials with analogous structures and similarly impressive mechanical properties to carbon nanotubes (CNTs), but unique chemistry and complimentary multifunctional properties, including higher thermal stability, electrical insulation, optical transparency, neutron absorption capability, and piezoelectricity. Over the past decade, advances in synthesis have made BNNTs more broadly accessible to the nanomaterials and other research communities, removing a major barrier to their utilization and research. Therefore, the field is poised to grow rapidly and see the emergence of BNNT applications ranging from electronics to aerospace materials. A key challenge, that is being gradually overcome, is the development of manufacturing processes to make “neat” BNNT materials. This overview highlights the history and current status of the field, providing both an introduction to this Focus Issue—BNNTs: Synthesis to Applications—as well as a perspective on advances, challenges, and opportunities for this emerging material.

Changes in optical properties transparency of pure and cobalt oxide (CoO)-doped lithium borate glasses have been investigated for fresh and γ-irradiated samples. These changes either in the transparency or color due to the variation of Co concentration or γ-irradiation doses indicated changes occurred inside the glass matrix. The ability of this glass to shield gamma ray, neutron, electrons, and protons was also examined. The calculations of optical band gap values showed a decrease, with the increase in CoO concentration, while the refractive index increased. Mass attenuation coefficient (MAC) of glasses was measured at 662, 1173, 1275 and 1333 keV energies by utilizing NaI(Tl) detector; also, theoretically by using Phy-X/PSD program derivative gamma shielding parameters have been studied. It was found that an increase in CoO % makes increment of gamma attenuation. Moreover, adding CoO improves neutron absorption due to the bigger cross section of Co atoms. Charged particles as (proton and electron); glass samples give good results at 10 keV‒10 MeV kinetic energy range computed by SRIM code. This paper provides complementary results to the authors of previous research studies that examined this glass as an electron beam irradiation dosimeter.

Neutron imaging offers additional information compared to X-ray imaging and finds widespread applications in various fields, including nuclear engineering, non-destructive industrial diagnostics, homeland security, archaeology, and cultural heritage preservation. Drawing on extensive expertise in 3D sensor technology, a 3D micro-structured sensor for thermal neutron detection and imaging is under study. These devices, named HYDE2, are crafted through a simplified fabrication process, featuring planar n-on-p pixels on the front side. On the back side, Deep Reactive Ion Etching selectively etches deep and narrow cavities, subsequently filled with appropriate converting materials such as 6LiF or 10B. The sensor is composed of 256x256 pixels of 55x55 μm2 size and is coupled with a Timepix read-out chip. In this work, GEANT4 simulations were conducted to investigate the thermal neutron absorption and conversion into charged particles, considering different geometries of the cavities and different conversion materials. Using Synopsys TCAD, the electric field map inside the sensor was determined, and aspects of charge generation, diffusion, and collection—which can degrade efficiency and diminish imaging performance due to charge loss and charge sharing events—were considered. This paper presents the primary outcomes of Monte Carlo and TCAD simulations, providing a more accurate estimate of the detection performance with this sensor type. These findings can prove highly beneficial for future research and the development of innovative 3D silicon detectors for neutron imaging.

Superfluid helium (He-4), due to its unique properties such as extremely low viscosity, high thermal conductivity, and negligible neutron absorption cross section, serves as an excellent coolant or moderator. Typically, the superfluid helium Ultra-Cold Neutron Source require maintaining the temperature of large amount of ultra-high purity superfluid He-4 below 1K. This prerequisite imposes stringent specifications on heat transfer, thermal insulation, and cooling process design within cryogenic systems. In this paper, a self-liquefying cryostat equipped with three separate helium intakes is designed to supply 7L superfluid helium at a temperature of 0.7K. By analyzing the heat transfer among the three helium fluid streams and the cold source, the appropriate types and size of heat exchangers were reasonably determined. Furthermore, Al 2 O 3 powder was employed to make the superleak, which is an important component within the system for purifying He-4. The influence of different pressing pressures on the physical properties of this superleak was also explored.