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Radiation-shielding is essential in fields involving storage and transport of radiation active material, such as medicine and nuclear engineering. The risk of radiation spill is a source of constant concern with its potential impact on local environment and life. Radiation spills that occur in laboratory are considered minor and containment of radiations in such cases using conventional techniques is not practical. Current practice involves using a suitable chemical absorbent, cleaning the spill region using agents and requires monitoring the spill region regularly for activity. Although this technique is effective in managing minor/laboratory grade spills, it requires careful application and constant monitoring before the area can be deemed safe for work. In this paper, we provide a detailed review of the radiation-shielding properties of polymer nanocomposites and their fabrication. The paper outlines radiation-shielding mechanisms, measurement of radiation attenuation, and factors that influence radiation attenuation. The review also compares analytical attenuation measurement methods against experimental methods. This review would be helpful in not only understanding the underlying energy transfer mechanism, but also aid in exploring polymer nano-composite materials as a viable green option for containing medium to low-level radiation spills. [ABSTRACT FROM AUTHOR]

Nano air channel transistors (NACTs) provide numerous advantages over traditional silicon devices, including faster switching speeds, higher operating frequencies, and enhanced radiation hardness attributable to the ballistic transport of electrons. In the development of field‐emission‐based integrated circuits, low‐power consumption rectifying nano air channel diodes (NACDs) play a crucial role. However, achieving rectification characteristics in NACDs is challenging due to their structural and material symmetry. This paper proposes a vertical GaN NACD with a consistent nano air channel fabricated using IC‐compatible processes. The GaN NACD exhibits an exceptionally low turn‐on voltage of 0.3 V while delivering a high output current of 5.02 mA at 3 V. Notably, it demonstrates a high rectification ratio of up to 2.2 × 105, attributing to significant work function disparities within the GaN‐Au structure, coupled with the reduction of Au surface roughness to minimize reverse current. Furthermore, the junction‐free structure and superior material properties of GaN enable the NACD to be suitable for use in radiation‐rich environments. With its potential as a fundamental component of ultrafast and ultrahigh‐frequency integrated circuits, this intriguing and cost‐effective rectifying diode is anticipated to garner widespread interest within the electronics community. [ABSTRACT FROM AUTHOR]

The results of experimental studies on attenuating neutron and photon radiation in a nuclear reactor using a protective metal hydride composite are presented. The distribution profile of the dose and spatial energy is obtained for primary and secondary gamma radiation. It is shown that the dose of gamma radiation behind the protection is associated with capturing gamma rays generated in the initial layer of the material. Based on the results obtained, the calculation model of the experiment is verified in the two-dimensional geometry for the properties of the material protecting the reactor. The verification involves the discrete ordinate method based on the DORT package. Deviations between the calculated and experimental values of the fast neutron relaxation lengths do not exceed 5%. The same deviations obtained for gamma radiation are under 7%, which confirms the validity of the calculation technique and the potential to apply the data obtained to proceed with designing radiation protection based on the metal hydride composite. [ABSTRACT FROM AUTHOR]

Abstract Nano air channel transistors (NACTs) provide numerous advantages over traditional silicon devices, including faster switching speeds, higher operating frequencies, and enhanced radiation hardness attributable to the ballistic transport of electrons. In the development of field‐emission‐based integrated circuits, low‐power consumption rectifying nano air channel diodes (NACDs) play a crucial role. However, achieving rectification characteristics in NACDs is challenging due to their structural and material symmetry. This paper proposes a vertical GaN NACD with a consistent nano air channel fabricated using IC‐compatible processes. The GaN NACD exhibits an exceptionally low turn‐on voltage of 0.3 V while delivering a high output current of 5.02 mA at 3 V. Notably, it demonstrates a high rectification ratio of up to 2.2 × 105, attributing to significant work function disparities within the GaN‐Au structure, coupled with the reduction of Au surface roughness to minimize reverse current. Furthermore, the junction‐free structure and superior material properties of GaN enable the NACD to be suitable for use in radiation‐rich environments. With its potential as a fundamental component of ultrafast and ultrahigh‐frequency integrated circuits, this intriguing and cost‐effective rectifying diode is anticipated to garner widespread interest within the electronics community.

The miniaturization of computer facilities conditioned by the miniaturization of applied components makes them very sensitive to radioactive radiation. This is where neutron and electromagnetic radiation come to the fore. The reason for the particularly pronounced effects of this radiation is the fact that they do not interact with the Coulomb force, so they pass (leave) the reactor vessel unimpeded. This study examines the reliability of magnetic and semiconductor computer memories in the field of neutron and gamma radiation. This study experimental, and conducted under well-controlled conditions. The combined measurement uncertainty of the experimental procedure is less than 5 %. Sophisticated methods of mathematical statistics were used to process the stochastic results of measurements.

The oxide dispersoids within ODS alloys can act as sinks for radiation-induced defects, such as vacancies and dislocation loops, effectively reducing their mobility and preventing their accumulation. This property is crucial for HEAs employed in radiation-intensive environments, such as nuclear reactors. The objective of this research is to examine the impact of rare earth elements (REE) such as Y 2 O 3 , Er 2 O 3 , Pr 2 O 3 , and Sm 2 O 3 , on Oxides Dispersion-Strengthened (ODS) FeCoNiCuZn High Entropy Alloys (HEAs). The mechanical alloying technique is employed to produce a high entropy alloy consisting of Fe, Co, Ni, Cu, and Zn in their raw form. Subsequently, the raw alloy powder is enriched with separate amounts of Y 2 O 3 , Er 2 O 3 , Pr 2 O 3 , and Sm 2 O 3. The microstructural analysis of the samples obtained from the mechanical alloying process was performed utilizing the X-ray diffraction (XRD) technique. In addition, scanning electron microscopy (SEM) was employed to analyze the ODS-HEA samples encoded S1, S2, S3, S4, and S5. To investigate the transmission properties of gamma-ray and neutron radiation, experimental studies are carried out using two types of detectors: Ultra High Purity Germanium (HPGe) detector and Canberra NP-100B BF3 gas proportional detector, respectively. The X-ray diffraction (XRD) spectra of samples did not display any observable peaks that could be attributed to the presence of dispersed rare earth element (REE) oxides. The uniform distribution of the metallic constituents that make up the High Entropy Alloy (HEA) is observed in the samples. Additionally, it can be observed that the implementation of the ODS-HEA technique, incorporating a 3% (wt.) Er 2 O 3 additive, results in the most advantageous results with respect to the characteristics of gamma ray absorption. The S3 sample demonstrated the greatest degree of neutron absorption, as demonstrated by a recorded value of 0.857 μSv/h, where the S1 sample demonstrated the minimum level of absorption, as evidenced by a recorded value of 0.452 μSv/h. Based on the observed effects on neutron and gamma-ray attenuation behaviors in ODS-HEAs, it can be concluded that Er 2 O 3 exhibits characteristics of a monotonic oxide. This feature is particularly advantageous for applications that necessitate a dual enhancement in these behaviors. It can also be concluded that the S1 sample may be deemed appropriate for situations where the utmost consistency of chain reactions in nuclear reactor fuel rods is desired, due to its possession of the lowest neutron absorption properties. [ABSTRACT FROM AUTHOR]

Introduction. Radioresistance of cancer cells is a serious problem in radiation therapy of tumor diseases. Radiosensitizers make malignant cells more sensitive to radiation and increase the effectiveness of radiation therapy; however, their widespread clinical use is limited by significant side effects. The development and study of new radiosensitizers seems to be an urgent task of modern pharmacology.Aim. The purpose of this work was to study the effectiveness of lithium ascorbate as a radiosensitizer under the influence of photon and neutron radiation in wide dose range.Materials and methods. Evaluation of the biological effect was carried out using the tumor line of prostate cancer PC-3. We used a cyclotron to produce neutron radiation and a Cobalt-60 source to produce gamma radiation.Results and discussion. We have proved an increase in the cytotoxic effect with the combined use of different types of ionizing radiation and lithium ascorbate. The resistance of the prostate cancer line to gamma radiation at an absorbed dose of 0.5–3.0 Gy was revealed. It was shown that tumor cells of prostate cancer are more sensitive to the effects of the study drug in minimal concentrations in combination with neutron irradiation compared to gamma radiation in the same absorbed dose. The main mechanism of the radiosensitizing action of lithium ascorbate is the local induction of oxidative stress, which synergistically enhances the action of ionizing radiation.Conclusion. The combination of lithium ascorbate with neutron radiation leads to a more pronounced resulting cytotoxic effect. An increase in the concentration of lithium ascorbate led to the pro-oxidative action with an increase in the damaging effect on cells.

Every computation presents a small chance that an unexpected phenomenon ruins or modifies its output. Computers are prone to errors that, although may be very unlikely, are hard, expensive or simply impossible to avoid. In the exascale, with thousands of processors involved in a single computation, those errors are especially harmful because they can corrupt or distort the results, wasting human and material resources. In the present work, we study the effect of ionizing radiation on several pieces of commercial hardware, very common in modern supercomputers. Aiming to reproduce the natural radiation that could arise, CPUs (Xeon, EPYC) and GPUs (A100, V100, T4) are subject to a known flux of neutrons coming from two radioactive sources, namely 252 Cf and 241 Am-Be, in a special irradiation facility. The working hardware is irradiated under supervision to quantify any appearing error. Once the hardware response is characterised, we are able to scale down the radiation intensity and to estimate the effects on standard data centres. This can help administrators and researchers to develop their contingency plans and protocols. [ABSTRACT FROM AUTHOR]

In Colombia, medical physics started formally about 3 decades ago. Two master's programs in medical physics initiated activities at two different universities. In particular, the master's program at the Pontificia Universidad Javeriana has been underway since 2012, and taking into account its projections, a team was established in 2015 in collaboration with the Universidad Distrital Francisco José de Caldas to conduct basic research on cancer treatment using neutron capture therapy (NCT). The primary goal of our initiative is to create the infrastructure required to adapt new technologies in our universities in the future. The long-term objective is to use neutron radiation to study not only NCT but also biomolecules, membranes, and materials. This will require the commissioning of an actual nuclear facility. Our group has been exclusively focused on carrying out calculations with GEANT4 because of its characteristics as open-source software, its accessibility, and its ample worldwide use and validation in the particle physics, nuclear physics, and medical physics communities. In this work, we present some results of our preliminary design for the ion accelerator column of a compact neutron generator. Also, we present the characterization of the kinematical and dose distributions of boron neutron capture processes using Geant4. [ABSTRACT FROM AUTHOR]

The article presents results of experimental determination of the characteristics of neutron fields behind the biological shielding of reactor facilities in the physical hall of pressurized water research reactors of the pool type. In the work, measurements of the energy distribution of the neutron radiation flux density, determination of anisotropy and correction factors for individual dosimeters were carried out. The energy distribution of the neutron radiation flux density was obtained using an MKS-AT1117M multi-sphere dosimeterradiometer with a BDKN-06 detection unit and a set of polyethylene moderator spheres. Based on the results of determining the energy distribution of the neutron radiation flux density, the average values of the neutron energy were established, which are in the energy range: 0.06–0.35 MeV. The difference between neutron fields at the surveyed personnel workplaces and neutron fields in which individual dosimeters are calibrated leads to an additional error in estimating such dosimetric quantities as ambient dose equivalent, individual dose equivalent or effective dose. The performed studies allow to improve the system of individual dosimetric control based on the cycle of improvements: new knowledge – experimental studies – implementation of research results – regulation of activities to reduce the exposure of workers – analysis of the data obtained – new knowledge. The radiation anisotropy was estimated from the results of measurements of the accumulated dose of neutron radiation by individual thermoluminescent dosimeters placed on four vertical planes of a human phantom. Adequate estimates of the effective dose to personnel can be obtained using correction factors for individual dosimeters. For various workplaces and methods, the correction factors range from 0.04 to 0.7.

Current work presents the synthesis of B2O3–Gd2O3–Li2O–Na2O–LiF‒Sm2O3 glass system via melt-quench approach and scrutiny of its mechanical, thermal, structural, physical, and nuclear radiation attenuation aspects. Raman scattering and Fourier transform infrared spectra revealed B–O stretching modes of BO4 groups linked to BO3 units with nonbridging oxygen atoms and BO3 and BO4 units' existence in the glass structure. By differential scanning calorimetry, glass transition and crystallization temperatures are identified. Relevant analysis showed all glasses' good thermal stability where glass transition temperature varied at 372–407 °C range. ΣR (fast neutron removal cross-section) and for energy 0.025 eV neutrons σT (total cross-section) are computed. In all glasses, 49.25 B2O3–10Gd2O3–10Li2O–10Na2O–20LiF-0.75Sm2O3 (mol%) sample holds higher ΣR (= 0.10207 cm−1). 48B2O3–10Gd2O3–10Li2O–10Na2O–20LiF–2Sm2O3 (mol%) glass possesses greater σT (= 736.675 cm−1) for thermal neutrons, hinting at added Sm2O3's favorable influence as Sm owns a better ability for neutron absorption than B. By Phy-X/PSD, μ/ρ (mass attenuation coefficient) is obtained at photon energy extent 15 keV‒15 MeV. Sm2O3 inclusion from 0 to 2 mol% minorly enhanced the μ/ρ values. Buildup factors estimated via geometric progression fitting method at 1–40 mean free path and energy 0.015–15 MeV span are maximal at medium energy region owing to Compton scattering process. 48B2O3–10Gd2O3–10Li2O–10Na2O–20LiF–2Sm2O3 (mol%) sample shows superior γ-ray blocking capacity in all glasses, suggesting Sm2O3's positive effect. Elastic moduli and Poisson's ratio are computed theoretically by bond compression and Makishima–Mackenzie models. It is identified that all glasses could tolerate longitudinal stress over shear stress.

Serpentine concrete has excellent neutron shielding property, which has been widely used in the nuclear industry and medical industry to shield neutron radiation in foreign countries. With the rapid development of nuclear industry and rich serpentine minerals in China, it should be a lot of research and application of serpentine concrete, however, in fact, serpentine concrete is not only less studied in China, but also its application is far less than abroad. Therefore, the characteristics of serpentine aggregate were summarized, and the physical properties, particle shape characteristics and chemical composition of three kinds of serpentine subspecies aggregate were compared. The influence of serpentine aggregate on concrete property was described in detail, and the shortcomings of current research on serpentine concrete were analyzed. The application status of serpentine concrete was combed. Finally, in order to promote further research and application of serpentine concrete in China, the future development of this field was prospected. [ABSTRACT FROM AUTHOR]

We report on the effects of large-area 4H-SiC Schottky barrier diodes on the radiation response to ionizing particles. Two different diode areas were compared: 1 mm × 1 mm and 5 mm × 5 mm. 6LiF and 10B4C films, which were placed on top of the diodes, were used as thermal neutron converters. We achieved a thermal neutron efficiency of 5.02% with a 6LiF thermal neutron converter, which is one of the highest efficiencies reported to date. In addition, a temperature-dependent radiation response to alpha particles was presented. Neutron irradiations were performed in a JSI TRIGA dry chamber and an Am-241 wide-area alpha source was used for testing the alpha response of the 4H-SiC Schottky barrier diodes. [ABSTRACT FROM AUTHOR]

The effects of neutron and gamma radiation on shielding materials directly influence the safety of nuclear facilities. In this study, a B4C/epoxy resin shielding material was fabricated. The mechanical properties, fracture microstructural morphology, characteristic groups, and thermal degradation of the shielding material under two different irradiation conditions, 1 MGy gamma and superimposed 1.19×1015 cm-2 neutron radiation, were compared. After gamma irradiation for 11.6 d and superimposed neutron irradiation for 3 h, the mechanical properties of the shielding material continued to decrease; however, they did not decrease to 50% of those before irradiation, and radiation degradation occurred instead of material failure. Compared with separate gamma irradiation, the peak intensity in the 1H-NMR spectra of the shielding material near δ=7 did not change significantly after the additional neutron irradiation, indicating that there was no further degradation of the C‒H bond on the benzene ring. At 50% loss in mass, the temperature decreased from 526.3 °C before irradiation to 453.2 °C after gamma irradiation and 463.9 °C after gamma superimposed neutron irradiation, demonstrating the decrease in thermal stability.

High radiation tolerance of functional materials in harsh environments is the key requirement for the operation of particle accelerators, medical devices, nuclear power plants, satellites, and spacecraft. Neutron and gamma (γ) radiation can seriously affect the functional properties of the irradiated materials and thus the performance of the entire device. In this work, the feasibility of using (1- x)Pb(Mg 1/3 Nb 2/3)O 3 – x PbTiO 3 (PMN–100 x PT) electrocaloric materials in applications where the material is exposed to high neutron and γ-radiation is investigated. For this purpose, three different compositions of PMN–100 x PT ceramics (x = 0, 0.1, and 0.35) were prepared and their dielectric, ferroelectric and electrocaloric properties were investigated before and after neutron and γ-irradiation. The samples were irradiated with a neutron fluence of 1015 to 1017 neutrons cm−2 with an energy of 1 MeV, which exceeds the largest expected neutron irradiation in the European Council for nuclear Research (CERN) and simultaneously exposed to γ-irradiation. The neutron and γ-radiation partially affect the functional properties of the PMN–35PT, the ceramic with distinct ferroelectric and weakened relaxor features, with some differences observed in the domain switching behavior, measured by conventional polarization versus electric field (P – E) hysteresis, at the highest radiation dose of 1017 neutrons cm−2. In contrast, the functional properties of the irradiated PMN and PMN–10PT samples with relaxor behavior are quite similar to those of the pristine samples, therefore, we conclude that these materials can be used as working materials in EC coolers exposed to such harsh environments. [ABSTRACT FROM AUTHOR]

The paper presents calculated data on a comparative assessment of the radiation-protective properties of materials based on titanium hydride obtained by the method of multigroup modeling of protection against neutron and gamma radiation. Two types of compositions behind the steel reactor vessel and lead shielding are considered. It is shown that gamma radiation behind the protection of titanium hydride is formed by capture radiation arising in the initial layers of the protection. Secondary gamma radiation generated during the passage of a neutron flux through the thickness of the composite does not have a noticeable effect on the value of the functionals of gamma quanta behind the shield. The high efficiency of materials based on titanium hydride shot is shown. Behind the protection of a composite based on titanium hydride shot 1 m thick, the dose rate of fast neutrons is three orders of magnitude lower, and the dose rate of gamma rays is two orders of magnitude less than that behind serpentinite concrete. The introduction of boron atoms into the composition of the composite, which has a large neutron absorption cross section in the thermal and epithermal regions of the spectrum, reduces the effect of accumulation of thermal neutrons and the level of captured gamma radiation, but does not affect the attenuation of fast neutrons. The necessity of using titanium hydride shot on a cement binder is shown, which prevents the formation of voids in the protection structure and the passage of neutrons. [ABSTRACT FROM AUTHOR]

The elasto-viscoplastic response of irradiated bainitic steels for pressure vessels of light water reactors is described by a multiscale micromechanical model. The model relies on a simplified set of complex constitutive equations describing intragranular flow under a wide range of temperatures, strain rates, and irradiation levels. These equations were themselves partially calibrated by multiscale analyses based on dislocation dynamics calculations, atomistic calculations, and experimental measurements. They include the contribution of jog drag, lattice friction, evolution of dislocation microstructures, and irradiation hardening. The scaling up of these intragranular laws to polycrystalline samples relies on a computational homogenization method which solves the field equations within periodic representative volume elements by means of Fast Fourier Transforms. This computational method proves advantageous relative to the finite element method in handling the complex microstructural morphology of the model required to achieve overall constitutive isotropy. Macroscopic simulations for uniaxial curves under different irradiation levels are first confronted to experimental curves to identify certain microscopic material parameters employed to describe the evolution of the mean-free path of dislocations with deformation. Subsequent comparisons for the evolution of the yield stress, irradiation hardening and the response to sudden strain-rate variations are then reported for a class of steels with various chemical compositions under wide ranges of temperature, loading rate and irradiation level. Good agreement is obtained in all cases. Finally, simulations are employed to explore the influence of the initial dislocation density on the intragranular stress and strain fields. An appreciable influence on the fields is observed during the elasto-viscoplastic transition but not deep in the plastic range. • Viscoplasticity of irradiated bainitic steels is derived by a micromechanical model. • The model equations cover a class of steels with various chemical compositions. • The field equations are solved on complex periodic RVE using a FFT method. • Macroscopic simulations for uniaxial loadings are consistent with experimental curves. • Initial dislocation distribution heterogeneity affects local fields at low deformation. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive bibliometric analysis to understand the evolution of scintillators as neutron detection from 2014 to 4 July 2023, utilizing data sourced from Scopus. The 312 selected articles were visualized using vosViewer and Tableau. This study delves into critical aspects, such as the growth of publication in this field over time, contributions made by various countries and their collaborative networks, top journals publishing articles related to scintillators as neutron detection, frequently cited documents used as references, and research trends over specific periods. The results show that research on scintillators for neutron detection has been popular since 2014, with at least 20 articles published yearly. The United States, China, France, and Italy have published the most papers, but Lithuania, Russia, India, and China have been the most active recently. The article provides researchers with an extensive overview of their field. This information empowers them to identify research gaps and find collaborators more efficiently. Overall, this analysis serves as a valuable resource for researchers seeking to advance their understanding of scintillators as neutron detection. • Evolution of scintillators as neutron detection from 2014 to 4 July 2023. • Scintillators for neutron detection popular since 2014 with 20 articles published yearly. • The United States, China, France, and Italy have published the most papers. • Lithuania, Russia, India, and China have been the most active recently. • This information to identify research gaps and find collaborators more efficiently. [ABSTRACT FROM AUTHOR]

This paper studies the suitability of neuromorphic event-based vision cameras for spaceflight and the effects of neutron radiation on their performance. Neuromorphic event-based vision cameras are novel sensors that implement asynchronous, clockless data acquisition, providing information about the change in illuminance $\ge 120dB$ with sub-millisecond temporal precision. These sensors have huge potential for space applications as they provide an extremely sparse representation of visual dynamics while removing redundant information, thereby conforming to low-resource requirements. An event-based sensor was irradiated under wide-spectrum neutrons at Los Alamos Neutron Science Center and its effects were classified. Radiation-induced damage of the sensor under wide-spectrum neutrons was tested, as was the radiative effect on the signal-to-noise ratio of the output at different angles of incidence from the beam source. We found that the sensor had very fast recovery during radiation, showing high correlation of noise event bursts with respect to source macro-pulses. No statistically significant differences were observed between the number of events induced at different angles of incidence but significant differences were found in the spatial structure of noise events at different angles. The results show that event-based cameras are capable of functioning in a space-like, radiative environment with a signal-to-noise ratio of 3.355. They also show that radiation-induced noise does not affect event-level computation. Finally, we introduce the Event-based Radiation-Induced Noise Simulation Environment (Event-RINSE), a simulation environment based on the noise-modelling we conducted and capable of injecting the effects of radiation-induced noise from the collected data to any stream of events in order to ensure that developed code can operate in a radiative environment. To the best of our knowledge, this is the first time such analysis of neutron-induced noise has been performed on a neuromorphic vision sensor, and this study shows the advantage of using such sensors for space applications.

Adequate shielding from ionizing radiations is essential in nuclear facilities because of such radiations’ adverse effects on humans in the event of unwanted or accidental exposure. In the current work, for four distinct compositions of B2O3-Li2O, Li2O-Na2O-K2O-B2O3, Gd2O3-SiO2-B2O3, and Bi2O3-Li2O-ZnO-B2O3 glass systems, neutron and γ-ray attenuation competencies combined with elastic features have been examined for feasible nuclear radiation protection purposes. ΣR (fast neutron removal cross-section) and for thermal energy neutrons σT (total cross-section) and SP (shielding percentage) were estimated. Comparably, in all samples, 50B2O3-10K2O-40Li2O (mol%) glass possesses larger ΣR (=0.11755 cm−1), whereas 25B2O3-37.5Si2O-37.5Gd2O3 (mol%) glass shows large σT (=646.171 cm−1) and SP for thermal neutrons at minimal thickness, indicating the included Gd2O3’s positive effect as element Gd has a high neutron absorption capacity. Employing the Phy-X/PSD program and MCNPX code, μ/ρ (mass attenuation coefficient) of all selected glasses is calculated for a γ-ray energy span of 0.015 – 15 MeV. Gd2O3 or Bi2O3 addition improved μ/ρ, and such increment is significant at low energies owing to PEA (photoelectric absorption) dominance and Gd or Bi K-edges. Also, for 15B2O3-10ZnO-5Li2O-70Bi2O3 (mol%) glass, μ/ρ has been derived by the WinXCOM program and FLUKA, Geant4, and PHITS codes, and a good accord between such simulated and theoretical μ/ρ outcomes is noticed following the calculated relative differences. Next, linear attenuation coefficient, effective atomic number and electron density, MFP (mean free path), TVL (tenth-value layer), HVL (half-value layer), and RPE (radiation protection efficiency) have also been evaluated. Comparatively, at 1.25, 0.662, and 0.2 MeV energies, 15B2O3-10ZnO-5Li2O-70Bi2O3 (mol%) sample possesses lower MFP and HVL than five SCHOTT AG commercial glass shields. Approximated RPE results affirmed all Gd2O3-SiO2-B2O3 and Bi2O3-Li2O-ZnO-B2O3 samples’ potent absorption (almost 100%) ability for lower energy γ-rays. Moreover, equivalent atomic number, and by geometric progression fitting process, within energy 15 keV–15 MeV extent for ten different penetration depths at 1–40 mfp span buildup factors have been assessed. 15B2O3-10ZnO-5Li2O-70Bi2O3 (mol%) glass exhibits better gamma-ray shielding effectiveness in all chosen samples, specifying Bi2O3’s favorable impact. Changes in photon shielding factors were interpreted following pair production, Compton scattering, and PEA processes. Later, elastic (Young’s (Y), bulk (K), shear (S), and longitudinal (L)) moduli and Poisson’s ratio values have been calculated for all inspected glasses. BC (bond compression) and M-M (Makishima–Mackenzie) models were utilized for such elastic traits reckoning. All K, Y, S, and L values’ trends for binary B2O3-Li2O glasses were identical in both BC and M-M models, and Kbc was found to be raised from 73.63 to 89.89 GPa, while KM–M increased from 75.35 to 180.53 GPa accordingly when Li2O content improved from 9.6 to 39.9 mol% in the chemical composition.

The influence of neutron and gamma irradiation on the low- and high-field dielectric and electrocaloric (EC) properties of Mn-doped 0.9Pb(Mg _1/3 Nb _2/3 )O _3 –0.1PbTiO _3 (PMN–10PT) ceramic is studied. Upon exposure to neutron fluences of up to 10 ^17 cm ^−2 and gamma-ray doses of up to 1200 kGy the Mn-doped PMN–10PT exhibits a lower saturated polarization, increased internal bias field and reduced EC temperature change. In comparison, the respective properties of the undoped PMN–10PT remain almost unchanged upon exposure to neutrons and gamma rays. In Mn-doped PMN–10PT, the acceptor-oxygen vacancy defect complexes, introduced via doping, contribute to the lowering of the threshold radiation dose that the material survives without noticeable changes in properties. Radiation-induced degradation of the EC response of Mn-doped PMN–10PT can be partially healed by annealing at 450 °C. The study provides guidance for designing EC ceramic materials for solid-state cooling applications in environments of high ionizing radiation, such as the medical field or space technologies.

The COherent Muon to Electron Transition (COMET) experiment aims to search for the neutrinoless muon to electron transition process with new sensitivity levels. The online trigger system is an integral part of achieving the sensitivity levels required and will be subject to an expected neutron fluence of up to $10^{12}\,\,n \cdot \mathrm {cm}^{-2}$ within regions inside the detector solenoid. Consequently, a significant number of soft errors in the logic of the onboard field programmable gate arrays (FPGAs) can occur, requiring error correction for single event upsets and firmware reprogramming schemes for unrecoverable soft errors. We studied the radiation tolerance of the COMET Phase-I front-end trigger system, called COMET TRIgger (COTTRI), subject to neutron fluence on order $10^{12}\,\,n \cdot \mathrm {cm}^{-2}$ with multiple error correcting codes and automatic firmware reconfiguration. The regions measured were the configuration random access memory (RAM), block RAM (BRAM) and also in a multigigabit transfer link using copper cables that will be used for communication between different trigger boards during Phase-I. The resulting cross sections observed suggest the most significant impact to the experiment will come from unrecoverable soft errors in configuration RAM (CRAM), with dead time expected to be 4.2% ± 1.3%. The effect of multibit errors in BRAM was found to be almost negligible in COMET Phase-I. In addition, multiple solutions have already been proposed in order to suppress these errors further. Soft errors observed in the multigigabit transfer links were measured to be of two orders of magnitude less impact compared to the unrecoverable errors in CRAM. We concluded that the COTTRI system meets the trigger requirement in COMET Phase-I. [ABSTRACT FROM AUTHOR]

In the paper, the necessity for carrying out spectrometric measurements of neutron fluxes in the nuclear industry in order to accurately estimate radiation density and dose characteristics is justified in terms of the inadequacy of current metrological and methodological support for both spectrometric and radiometric measurements of random neutron fluxes. The authors briefly describe the concept of a real-time multidetector neutron spectrometer along with results obtained from a prototype study. In order to increase the reliability of neutron measurements, an innovative concept for verifying a real-time multidetector neutron spectrometer is proposed. This concept involves using several dozens of reference fields exhibiting diverse and precisely known spectra, rather than a single flux, whose spectrum is unknown. The developed testing and verification system is used to carry out a verification. Reference neutron fields produced by this system to exhibit various energetic spectral forms are mathematically modeled. The spectra of the generated reference neutron fields are computed using a system simulated by Monte Carlo software during laboratory tests of a prototype real-time multidetector neutron spectrometer-dosimeter. It is proposed to train a neural network embedded in the multidetector neutron spectrometer-dosimeter on an extended set of basic spectra, which, in addition to the reference field spectra, includes neutron flux spectra reliably known from literature descriptions. A procedure for forming a set of the simulated realizations of training and verification samples used in the neural network training is presented. It is shown that energy errors of the proposed real-time multidetector neutron spectrometer-dosimeter can be avoided during neutron flux measurements, even when performing verification in the reference fields exhibiting a limited variety of spectral shapes. The paper justifies the possibility of minimizing the energy errors of the existing neutron radiometer-dosimeters in the course of the verification performed in the neutron reference fields of the developed testing and verification system. [ABSTRACT FROM AUTHOR]

Homogenized descriptions are provided for polycrystalline solids deforming in accordance with certain crystal plasticity laws recently proposed for neutron-irradiated bainitic steels. These laws express intragranular plastic slip rates in terms of resolved shear stresses and key microstructural features, such as densities of forest dislocations and of solute clusters, for a wide range of deformation rates, temperatures, and radiation doses. The elastic domain is delimited by thresholds on the resolved stresses that depend on dislocation densities in an intricate manner, and the plastic hardening is described by evolution laws of the Mecking–Kocks type for the dislocation densities with plastic slip. However, thresholds also depend nonlinearly on the resolved stresses themselves. Full-field homogenized descriptions are generated with a Fast Fourier Transform algorithm implemented in the computer code CraFT, while mean-field homogenized descriptions are generated by means of a linear-comparison scheme based on a generalized-secant linearization of the crystal plasticity laws. Multiple ways of accounting for plastic hardening in the mean-field descriptions are explored. Sample results are reported in the form of uniaxial traction curves and concomitant dislocation density evolutions under different scenarios. Overall, the generalized-secant linearization is found to provide an appropriate compromise between precision and mathematical complexity to generate homogenized descriptions for the elastoplastic response of polycrystalline media governed by complex crystal plasticity laws. • New homogenized descriptions for polycrystals with complex crystal plasticity laws • Mean-field descriptions are confronted to Full-Field descriptions. • Multiple ways of accounting for plastic hardening in the mean-field descriptions • A generalized-secant linearization is found most appropriate • Slip-rate measures incorporating intragranular fluctuations are found appropriate [ABSTRACT FROM AUTHOR]

This paper presents the results of an examination of function stability of high-voltage asynchronous motors exposed to ambient strain caused by combined neutron and gamma radiation. This problem appears in practice when a high-voltage asynchronous motor is used in nu- clear power plants where it can be exposed to this type of ambient strain. The failure of the engine's operation under such conditions may have unexpected consequences. As more than 50 % of failure (malfunction) of high-voltage asynchronous motors is caused by damage to stator insulation, the focus of the paper was on testing the effects of combined neutron and gamma radiation on stator insulation. The tests were carried out under well-controlled laboratory conditions on samples taken from both new and used factory coil windings. Two-layer samples were used to record partial discharge threshold voltage and breakdown voltage. By comparing the experimentally obtained results with the applicable mathematical-statistical procedure, an estimate was made of the aging acceleration of stator insulation and the time duration of reliable operation of high-voltage asynchronous motor was determined by life-time exponent. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 171007]

Materials capable of converting ionizing radiation into light photons are called scintillators, some have specific efficiencies for certain applications and types of radiation, e.g. gamma, X-ray, alpha, beta and neutrons. CsI:Tl and NaI:Tl crystals are commonly found in the market because they have several applications, but few studies have been done on lithium doped cesium iodide crystal (CsI:Li). The lithium element, in this crystal used as a dopant, is also exploited as a converter for neutron detection, as it has a shock section of 940 barns for thermal neutrons. The study of the CsI:Li crystal is convenient considering the natural abundance of the lithium element with 7.5%, besides the interest in having a low cost national scintillator material with an opportunity to search the response of a detector for different types of radiation. The CsI:Li crystal was grown with molar concentration 10-4 to 10-1, using the vertical Bridgman technique. The parameters involved in the growth process were investigated. The transmittance was evaluated in the spectral region from 190 nm to 1100 nm. Luminescence emission spectra for the CsI:Li crystal were evaluated by photometric analysis of the crystal stimulated with a 137Cs (662 keV) source in front of the coupled sample at the monochromator input. The crystals showed of maximum luminescence intensity at the wavelength of 420 nm. The response of the scintillators when excited with gamma radiation of 241Am, 133Ba, 22Na, 137Cs, 60Co and neutron radiation from the AmBe source, with energy range of 1 MeV to 12 Mev was evaluated.

Different isotopes may exhibit different resistance against the displacement damage induced by neutron radiations. To examine the difference in silicon isotopes, we calculate the damage functions of 28Si, 29Si, 30Si and the natural silicon under intermediate neutron (10−6–0.1 MeV) and fast neutron (>0.1 MeV) radiations based on radiation damage theory and the Neutron Nuclear Reaction Evaluation Database (ENDF/B-VIII.0). Their accumulative displacement per atom (DPA) values under the neutron radiation of nuclear accident emergency response or cosmic space are also investigated. The calculated radiation damage functions and DPAs indicate that 30Si endures at least 10–15% less displacement damage compared with 28Si, 29Si and the natural silicon under intermediate and fast neutron radiations. Therefore, we propose to use 30Si-enriched silicon in semiconductor devices to enhance the neutron radiation resistance and extend the service life in radiative circumstances. [ABSTRACT FROM AUTHOR]

The combined effect of the irradiation with a proton pencil scanning beam (PBS) at a total dose of 80 Gy and neutron radiation at a dose of 5 Gy on the growth of solid Ehrlich ascites carcinoma (EAC) and the remote effects in tumor-bearing mice was studied. Combined irradiation of mice with neutrons before and after irradiation with PBS, as well as irradiation only with PBS, effectively suppressed the growth of solid EAC within 1 month. In terms of the frequency and severity of radiation-induced skin reactions of mice observed 15–40 days after therapy, neutron irradiation after the irradiation with PBS showed better values of these parameters as compared to only PBS; however, exposure to neutrons before PBS was more damaging as compared to the other two options. It was also shown that the tumor relapse rate in the groups of animals with combined irradiation was higher, and the total lifespan was lower than the group of mice irradiated with PBS alone. [ABSTRACT FROM AUTHOR]

Wide-gap semiconductor SiC is generally considered as a superior candidate for high-radiation applications, due to its higher displacement energy for both Si and C lattice atoms. In this work, we find that the current gain ($\beta $) of 4H-SiC bipolar junction transistors (BJTs) can severely deteriorate after neutron irradiation. Deep-level transient spectroscopy (DLTS) reveals that two major carrier-killer centers, Z1/2 and EH6/7, were produced in neutron-irradiated devices. Surprisingly, we find that the shallow Z1/2 center can play a dominant role over the deep EH6/7 defects in carrier recombination under high-injection conditions, which contributes to the unusual smaller hole capture cross section than that of the electron one, as indicated by the first-principles calculations. Finally, technology computer aided design (TCAD) simulation confirms that the enhanced carrier recombination from the Z1/2 centers is responsible for the degraded performance of SiC BJTs after irradiation. Our findings not only provide a deep insight into the underlying physics for displacement damage in SiC BJTs, but also are of interest for technological applications field related to high-energy particle irradiation or implantation. [ABSTRACT FROM AUTHOR]

Background: The investigation of the low doses of ionizing radiation is still a great importance for identification of the threshold of harmful effect and potential hormetic effect of low doses. Objectives: The purpose of investigation was to evaluate the stress response in human buccal epithelium cells induced by low intensive neutron radiation. Materials and Methods: The level of chromatin condensation in interphase nuclei was applied for assessment of the cell reaction to stress. Exfoliated human buccal epithelium cells were collected, placed in the 3.03 mM phosphate buffer solution (pH=7.0) with addition of 2.89 mM CaCl2 and exposed to neutron radiation from 2 Pu-Be sources IBN-17. The heterochromatin granule quantity (HGQ) assessments were done after orcein staining that had been immediately performed after cell exposure to neutron radiation in the dose range from 2.3 mSv to 146.0 mSv. Also the effect of fast neutron radiation in the dose of 11.4 mSv on human buccal epithelium cells was investigated in 1-64 min after exposure. The HGQ in every variant of experiment was assessed in 30 nuclei in 3 separate experiments. The mean HGQ and standard error of mean were assessed in every experiment. Results: Neutron radiation induced the increase of HGQ. Partially slowed neutrons have less influence on neutron-induced HGQ increase than only fast neutrons especially with 1 min delay after exposure. Fast neutrons induce heterochromatinization in cell samples irradiated with doses 4.6–36.5 mSv. Further increase of dose has led to return of HGQ to control levels. After cell exposure to fast neutron flow (11.4 mSv) the peaks of chromatin condensation were observed for time intervals 2–8 and 32–64 min after cell exposure to radiation. Conclusions: Qualitative characteristic of neutron radiation (slow/fast neutrons) influences the rate of cell stress response as revealed by chromatin condensation in cell nuclei. It was demonstrated that there is a threshold dose above which cells are able to develop stress response to neutron radiation. The dose-response dependence is non-monotonous and is of wave-like form. Described phenomena may be explained by the effect of hormesis.

Epoxy resin is a thermoset polymer and is one of the main candidates for radiation shielding application. In this investigation, carbon, hydrogen, and nitrogen analysis showed that the presence of the light element of nitrogen in cured epoxy could lead to more effective neutron shielding ability compared with physical curing. The effect of neutron irradiation of amine-cured epoxy was studied by infrared spectroscopy. Neat epoxy samples were irradiated at the core of the Tehran Research Reactor in the same neutron flux in the order of 1013 (neutron/cm2×s) at several radiation times (up to 12 h). The results indicated that neutron irradiation caused moderate changes in peak absorption locations of epoxy spectra. This result indicates that, in this neutron flux and irradiation time, the molecular structure of epoxy remains stable.

This paper provides the results of studying a sealing material based on low-molecular dimethylsiloxane rubber modified with erbium oxide for creating a composition with enhanced physical mechanical and electric properties and handling abilities and with the capability of partially absorbing neutron and ionizing radiation due to the specifics of the filler. It is shown that the addition of erbium oxide to the composition allows using it for sealing radioelectronic components used on exposure to neutron and ionizing radiation. [ABSTRACT FROM AUTHOR]

We report on influence of neutron radiation on majority and minority carrier traps in n-type 4 H -SiC. Together with the increase of the well-known carbon vacancy (V C) majority carrier related trap, neutron irradiation has introduced two deep traps, labeled as EH1 and EH3 with the activation energies for electron emission estimated as 0.4 and 0.7 eV bellow the conduction band, respectively. Based on Laplace deep level transient spectroscopy (DLTS) results, we have assigned EH1 trap to silicon vacancy (V Si). Two minority carrier traps labelled as B and D-center were detected by minority transient spectroscopy (MCTS) and assigned to substitutional boron B Si and B C , respectively. Activation energies for hole emission for B and D-center are estimated as 0.27 and 0.60 eV above the valence band, respectively. We have identified two emission lines for D-center by Laplace-MCTS measurements and assigned them to B C sitting at hexagonal (− h) and cubic (− k) lattice sites. [ABSTRACT FROM AUTHOR]

In this article, we propose a method for designing online totally self-checking (TSC) comparators for TSC systems implementable on field-programmable gate arrays (FPGAs). This method can be used to conduct exhaustive online diagnostics of each lookup table (LUT), which involves mapping the fundamental components of the comparator, with a small number of test patterns by directly measuring output of each LUT. Our method drastically reduces the number of test patterns for exhaustive diagnosis on the order of the input number n [ $O(n)$ ] (n is the input number to the comparator) while maintaining 100% coverage, even if we only know the specifications of the LUT without knowing its detailed structure. FPGAs will be easily applicable to systems that require high dependability. To confirm the soft error rate (SER) in a static random-access memory (SRAM)-based FPGA, we also conducted an experiment involving a single-event upset (SEU) caused by neutron radiation. For this experiment, we designed an FPGA implementation of 1575 identical dual-modular-redundant TSC comparators. The experiment was conducted for 10.4 h, and 34 errors were observed regarding such failures in comparator function. The evaluated SER for the TSC comparator with the proposed method was 0.055 FIT at sea level of New York City. [ABSTRACT FROM AUTHOR]

The effects of 14-MeV neutron displacement damage (DD) on waveguide (WG)-integrated germanium-on-silicon p-i-n photodiodes (PDs) for silicon photonics have been investigated up to the fluences of 7.5 × 1012 n/cm2 (14 MeV) or 1.4 × 1013, n1−MeVeq/cm2(Si). This article includes the measurements of dark current–voltage characteristics across temperature from 150 to 375 K, measurements of PD junction capacitance, spectral response measurements from 1260 to 1360 nm, and frequency-response measurements. The devices are found to be susceptible to DD-induced carrier removal effects; however, they also continue to operate without meaningful impact to performance for the DD dose levels examined. Since the PD test chips include silicon photonic integrated grating couplers and WGs, which carry the optical signal to the PD, some assessment of the impact of DD on these passive devices can also be inferred. This article does not examine the short-term annealing or transient behavior of the DD, and instead, it has only considered the lasting damage that remains after any initial period of room-temperature annealing. [ABSTRACT FROM AUTHOR]