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Nuclear proliferation literature typically differentiates supply-side and demand-side factors influencing the spread of nuclear weapons. These distinct approaches to the proliferation puzzle raise the following empirical questions: Does nuclear supply stimulate states' demand for nuclear weapons? Conversely, does the demand for nuclear weapons really facilitate the acquisition of nuclear supply? If such endogeneity exists between the demand-side and supply-side determinants, how would it cause empirical bias in the estimation of their effects on nuclear proliferation? This article aims to unpack endogenous mechanisms of nuclear demand and nuclear supply over the course of nuclear proliferation. In particular, it examines two potential sources of endogeneity: (1) simultaneous interactions between states' nuclear development decisions and nuclear technological capability and (2) selection bias in nuclear development. To address each source of endogeneity, simultaneous equation models and the duration models with selection are estimated, respectively. Contrary to what recent supply-side literature suggests, the empirical analyses reveal that states' nuclear demand is primarily driven by external security threats instead of their existing nuclear technology, and that their successful acquisition of nuclear technology mainly follows as the result of nuclear development efforts but does not necessarily depend on individual supply-side factors. This article addresses the typical inference issues in nuclear proliferation research and contributes to our synthetic understanding of proliferation mechanisms. [ABSTRACT FROM AUTHOR]

Radiopharmaceuticals constitute the backbone of nuclear medicine research and have been commonly used in diagnostic imaging and radionuclide therapy. In the past, there has been a strong emphasis on the meticulous design and development of radiotheranostics for targeted molecular imaging and therapy of different types of tumors. Theranostic radiopharmaceuticals offer synergistic advantages of simultaneous molecular imaging and radionuclide therapy all in one molecule. Owing to their successful pre‐clinical and clinical applications, many new theranostic radiopharmaceuticals have been explored in recent years. This review aims to provide a comprehensive overview of the design and the structural framework of theranostic radiopharmaceuticals. In this review, we have primarily focused on the different types of chelating agents, linkers, and radionuclides used for the development of potential radiotheranostics. In addition, this review also summarizes the classification and the different categories of theranostic radiopharmaceuticals such as molecular radiotheranostics and nano‐radiotheranostics along with their pre‐clinical and clinical theranostic applications. The recent developments and the theranostic applications of small molecule‐based radiotheranostics, antibody‐based radiotheranostics, peptide‐based radiotheranostics, and nanoparticle‐based radiotheranostics have also been reviewed for inspiring research efforts towards the development of efficient radiotheranostics. [ABSTRACT FROM AUTHOR]

Preparation of in‐house reference materials of two different graded coal samples involves quality control in terms of chemical characterization. Neutron and proton‐based nuclear analytical techniques have been explored here using high flux nuclear research reactor and low energy proton accelerator. Concentrations of trace elements such as Sc, Cr, Fe, Co, Sb, Ce, Th, U, Eu, Hf, and Rb were determined by neutron activation analysis (NAA) with adequate accuracy and precision. Coal ash content can be derived from the inorganic oxide constituents (Na2O, MgO, Al2O3, SiO2, Fe2O3, TiO2, K2O and CaO). Coal‐1 was found to contain slightly higher ash content (∼35%) with low calorific value (C content ∼49% obtained from, pulsed fast and thermal neutron activation [PFTNA]) as compared to coal‐2 (∼33%). Ion beam analysis (IBA) technique (particle induced gamma‐ray emission [PIGE]) was utilized for quantification of inorganic major elements. Thermal and fast neutron probed nuclear methods like NAA using pneumatic carrier facility (PCF) and PFTNA in conjunction with IBA have proved their excellence for nondestructive chemical characterization. Energy dispersive X‐ray fluorescence (EDXRF) was also utilized as an alternate analytical technique for concentration determination of K, Ca, Fe, Ti, Zn, and Rb as a part of QC exercise. [ABSTRACT FROM AUTHOR]

The McMaster nuclear reactor (MNR) is an important research facility that not only provides researchers with neutrons for fundamental science, but also supplies the medical industry with isotopes used for cancer treatment. To ensure the safety and performance of the MNR, modeling of the thermal hydraulics during nominal and accidental conditions is required. For such a task, system codes are customarily used. While system codes can assess the safety aspects of complex thermal–hydraulic systems, the question arises whether such systems can be modeled appropriately in a three-dimensional manner, such as computation fluid dynamics (CFD), while capturing the thermal mixing of the coolant. Modeling the thermal hydraulics of nuclear research reactors using CFD is relatively new. Therefore, validating such methods against experimental data is of utmost importance. The validation of CFD is the main focus of this work. More specifically, the influence of the loss of heat sink on the pool temperature is assessed using the CFD code Ansys CFX. The validation basis was provided by an experiment performed at the MNR in March 2023. In this experiment, the secondary heat removal system was intentionally shut down, and the pool temperature was measured in a few positions. The results obtained by modeling the loss of heat sink in the MNR using Ansys CFX agree well with the experiment. [ABSTRACT FROM AUTHOR]

Purpose: To ensure comparable PET/CT image quality between or within centres, clinical inter-system performance comparisons following European Association of Nuclear Medicine Research Ltd. (EARL) guidelines is required. In this work the performance of the long axial field-of-view Biograph Vision Quadra is compared to its predecessor, the short axial field-of-view Biograph Vision. Procedures: To this aim, patients with suspected tumour lesions received a single weight-based (3 MBq/kg) 2-deoxy-2-[18F]fluoro-D-glucose injection and underwent routine clinical (∼ 15 min) scans on the Vision and 3-min scans on the Quadra in listmode in balanced order. Image quality (IQ), image noise (IN), and tumour demarcation (TD) were assessed visually by four nuclear medicine physicians using a 5-point Likert scale and semiquantitative analysis was performed using standardised uptake values (SUVs). Inter-reader agreement was tested using Wilcoxon's signed rank test and the SUVs were statistically compared using a paired t-test. Results: Twenty patients (mean age, 60 years ± 8.8 [standard deviation], 16 male) were enrolled. Inter-reader agreement ranged from good to very good for IQ and IN (0.62 ≤ W ≤ 0.81), and fair for TD (0.29 ≤ W ≤ 0.39). Furthermore, a significant difference was found for TD (p = 0.015) between the systems, showing improved TD for the Quadra. Conclusion: This study demonstrates that the Quadra can be used in routine clinical practice with multiple PET/CT systems or in multicentre studies. This system provides comparable diagnostic image quality and semiquantitative accuracy, improved TD, and has the advantage of shorter scan durations. [ABSTRACT FROM AUTHOR]

The last decade has seen the development and application of data-driven methods taking off in nuclear engineering research, aiming to improve the safety and reliability of nuclear power. This work focuses on developing a reinforcement learning-based control sequence optimization framework for advanced nuclear systems, which not only aims to enhance flexible operations, promoting the economics of advanced nuclear technology, but also prioritizing safety during normal operation. At its core, the framework allows the sequence of operational actions to be learned and optimized by an agent to facilitate smooth transitions between the modes of operations (i.e., load-following), while ensuring that all safety significant system parameters remain within their respective limits. To generate dynamic system responses, facilitate control strategy development, and demonstrate the effectiveness of the framework, a simulation environment of a pebble-bed high-temperature gas-cooled reactor was utilized. The soft actor-critic algorithm was adopted to train a reinforcement learning agent, which can generate control sequences to maneuver plant power output in the range between 100% and 50% of the nameplate power through sufficient training. It was shown in the performance validation that the agent successfully generated control actions that maintained electrical output within a tight tolerance of 0.5% from the demand while satisfying all safety constraints. During the mode transition, the agent can maintain the reactor outlet temperature within ± 1.5 °C and steam pressure within 0.1 MPa of their setpoints, respectively, by dynamically adjusting control rod positions, control valve openings, and pump speeds. The results demonstrate the effectiveness of the optimization framework and the feasibility of reinforcement learning in designing control strategies for advanced reactor systems. [ABSTRACT FROM AUTHOR]

A scheme for a quasi-monoenergetic high-flux neutron source with femtosecond duration and highly anisotropic angular distribution is proposed. This scheme is based on bulk acceleration of deuteron ions in an optical trap or density grating formed by two counter-propagating laser pulses at an intensity of ∼ 1 0 16 W / c m 2 in a near-critical-density plasma. The deuterons are first pre-accelerated to an energy of tens of keV in the ambipolar fields formed in the optical trap. Their energy is boosted to the MeV level by another one or two laser pulses at an intensity of ∼ 1 0 20 W / c m 2 , enabling fusion reactions to be triggered with high efficiency. In contrast to previously proposed pitcher–catcher configurations, our scheme can provide spatially periodic acceleration structures and effective collisions between deuterons inside the whole target volume. Subsequently, neutrons are generated directly inside the optical trap. Our simulations show that neutron pulses with energy 2–8 MeV, yield 1018–1019n/s, and total number 106–107 in a duration ∼ 400 fs can be obtained with a 25 μm target. Moreover, the neutron pulses exhibit unique angularly dependent energy spectra and flux distributions, predominantly along the axis of the energy-boosting lasers. Such microsize femtosecond neutron pulses may find many applications, such as high-resolution fast neutron imaging and nuclear physics research. [ABSTRACT FROM AUTHOR]

In view of the complexity and importance of nuclear research reactor (NRR) installations, it is imperative to uphold high standards of reliability and quality in the electricity being supplied to them. In this paper, the performance of low-voltage (LV) distribution feeders integrated with NRRs is improved in terms of reduced distribution loss, improved voltage profile, and reduced greenhouse gas (GHG) emissions by determining the optimal location and size of photovoltaic (PV) systems. In the second stage, the power quality of the feeder is optimized by reducing the total harmonic distortion (THD) by optimally allocating D-STATCOM units. In the third and fourth stages, the reliability and resilience aspects of the feeder are optimized using optimal network reconfiguration (ONR) and by integrating an energy storage system (ESS). To solve the non-linear complex optimization problems at all these stages, an efficient meta-heuristic Chernobyl disaster optimizer (CDO) is proposed. Simulations are performed on a modified IEEE 33-bus feeder considering the non-linear characteristics of NRRs, variability of the feeder loading profile, and PV variability. The study reveals that the proposed methodology can significantly improve the service requirements of NRRs for attaining sustainable research activities. [ABSTRACT FROM AUTHOR]

This study aims to explore the correlation between the operational task complexity of nuclear power plant (NPP) operators and electroencephalogram (EEG) features. Initially, we segmented EEG signals according to operational steps and extracted a total of 120 time domain, frequency domain, and time-frequency domain features. Subsequently, we applied an adaptive principal component analysis (PCA) dimensionality reduction method to process the features. On the other hand, three experts were invited to evaluate the complexity of the operational tasks, and their evaluation data were synthesized using a group decision-making approach. A correlation analysis was performed between these data and the PCA-reduced feature data, identifying the features with the highest correlation coefficient for each participant. Then we built a long short-term memory model with the data of the first group of participants to predict the task complexity value and tested it with the data of the second group of participants. Testing the model with data from the second group yielded favorable results, with a training set mean squared error (MSE) of 0.025 and a testing set MSE of 0.078. The results of this study indicate a significant correlation between specific EEG features and task complexity in the operational tasks of NPP operators. The model established through a combination of group decision making and machine learning methods effectively predicted the task complexity levels for operators in different operational tasks. This research provides a new perspective on NPP operators' cognitive load and operational tasks, holding practical significance for operator training and workload management. [ABSTRACT FROM AUTHOR]

The process of radiological characterization involving all the systems, structures, equipment, and components resulting from the decommissioning of the VVR-S nuclear research reactor at the Horia Hulubei National Institute for Physics and Nuclear Engineering was a continuous journey marked by ongoing research, specialized training, and the accumulation of invaluable experience. Recognizing the significance of protecting the expertise gained during this effort, this paper aims to share several key insights collected from the radiological characterization process. In particular, the focus is placed on elucidating various methodologies and techniques utilized in gamma-ray spectrometry. The aim of delving into these specific aspects is to offer practical lessons that can serve as valuable guidance for future efforts in radiological characterization within similar contexts. Through the dissemination of these insights, it is hoped that the collective knowledge and expertise amassed during the radiological characterization of the VVR-S nuclear research reactor decommissioning can be effectively preserved and utilized for the benefit of future projects in the field. [ABSTRACT FROM AUTHOR]

Electron Beam Ion Traps (EBITs) serve as efficient tools for producing and studying highly charged ions. In response to the diagnostic requirements of upcoming magnetic confinement fusion devices, a medium-energy atomic spectra research platform based on a compact EBIT is developed. This platform achieves a central magnetic field of up to 1.0 T, with electron beam currents reaching 20 mA and electron energies up to 30 keV, similar to the electron temperature on fusion reactors. The developed atomic spectra platform successfully provided spectral data for elements such as argon, xenon, iron, and tungsten. This platform stands as a valuable asset for advancing research in nuclear fusion, particularly concerning impurity spectroscopic diagnostics. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model derived from an equivalent electrical circuit to describe the dynamic behavior of the high-voltage terminal of a tandem Van de Graaff accelerator. Two approaches are presented for modeling the transit time of the current flowing through the corona needles. The first one considers an equivalent self-inductance in the corona triode, whereas, in the second one, the transit time is represented by a delay in the corona current. The validation of the proposed models was carried out through experimental tests developed at the National Nuclear Research Institute of Mexico. Furthermore, two strategies for controlling the slow variations of the terminal voltage limited by the slow response of the control loop based on corona discharge are evaluated: a Proportional–Integral–Derivative controller and a sliding mode controller. The Root-Mean-Squared Error calculation leads to the conclusion that both control strategies are suitable for regulating the voltage at the accelerator potential terminal. However, the sliding mode controller leads to an overshoot-free response and a shorter settling time. [ABSTRACT FROM AUTHOR]

The Lanzhou Heavy Ion Research Facility (LIRF) is the largest heavy ion research facility in China, providing a substantial volume of experimental data for fundamental research in nuclear physics. The Topmetal-CEE is a pixel readout chip specifically designed for tracking detectors. Within the Topmetal-CEE framework, the front-end amplifier and comparator necessitate precisely adjustable bias voltages. Hence, in this paper, a 14-bit resolution DAC with an R-2R resistor network structure is designed, along with an amplifier featuring high driving capabilities as the DAC driver, thus preventing potential impedance issues when driving large pixel arrays. Test results demonstrate that the DAC module, operating under a 3.3 V supply voltage, can consistently output voltages ranging from 0 to 1.8 V. Furthermore, the differential non-linearity error is less than 1.07 LSB, and the integral non-linearity error is less than 1.57 LSB. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article discusses the field of nuclear physics and its various applications and frontiers. It highlights the importance of collaboration between theory and experiment in making breakthroughs in the field. The article includes contributions from researchers in different subfields of nuclear physics, such as nuclear structure, reactions, dynamics, hadron physics, nuclear astrophysics, and neutrino physics. It also discusses the use of different methodologies, including Monte Carlo approaches and ab initio methods. The article concludes by mentioning upcoming facilities and future opportunities for nuclear physics research. [Extracted from the article]

The Facility for Antiproton and Ion Research (FAIR) is in its final construction stage next to the campus of the Gesellschaft für Schwerionenforschung Helmholtzzentrum for heavy-ion research in Darmstadt, Germany. Once it starts its operation, it will be the main nuclear physics research facility in many basic sciences and their applications in Europe for the coming decades. Owing to the ability of the new fragment separator, Super-FRagment Separator, to produce high-intensity radioactive ion beams in the energy range up to about 2 GeV/nucleon, these can be used in various nuclear reactions. This opens a unique opportunity for various nuclear structure studies across a range of fields and scales: from low-energy physics via the investigation of multi-neutron systems and halos to high-density nuclear matter and the equation of state, following heavy-ion collisions, fission and study of short-range correlations in nuclei and hypernuclei. The newly developed reactions with relativistic radioactive beams (R3B) set up at FAIR would be the most suitable and versatile for such studies. An overview of highlighted physics cases foreseen at R3B is given, along with possible future opportunities, at FAIR. This article is part of the theme issue 'The liminal position of Nuclear Physics: from hadrons to neutron stars'. [ABSTRACT FROM AUTHOR]

In synchrotrons, accurate knowledge of the magnetic field generated by bending dipole magnets is essential to ensure beam stability. Measurement campaigns are necessary to characterize the field. The choice of the measurement method for such campaigns is determined by the combination of magnet dimensions and operating conditions and typically require a trade-off between accuracy and versatility. The single stretched wire (SSW) is a well-known, polyvalent method to measure the integral field of magnets having a wide range of geometries. It, however, requires steady-state excitation. This work presents a novel implementation of this method called pulsed SSW, which allows the system to measure rapidly time-varying magnetic fields, as is often needed, to save power or gain beam time. We first introduce the measurement principle of the pulsed SSW, followed by a combined strategy to calculate the absolute magnetic field by incorporating the classic DC SSW method. Using a bending magnet from the Proton Synchrotron Booster located at the European Organization for Nuclear Research as a case study, we validate the pulsed SSW method and compare its dynamic measurement capabilities to a fixed induction coil, showing thereby how the coil calibration must be adjusted according to the field level. Finally, we assess the method's measurement accuracy using the standard SSW as a reference and present an analysis of the primary noise contributors. [ABSTRACT FROM AUTHOR]

The article discusses the n_TOF facility at CERN, which is a research facility designed for studying neutron-induced nuclear reactions. The facility uses a pulsed white neutron source and has three experimental areas where reactions are studied. The article highlights the importance of the neutron source intensity and energy distribution, the repetition rate of neutron-generating pulses, the time resolution of the neutron beam, and the background conditions for conducting accurate experiments. The facility's core program focuses on measuring neutron-induced reaction cross-sections for various applications, including nuclear astrophysics and advanced nuclear technologies. The article also mentions the facility's continuous upgrades and improvements, as well as the collaborative nature of the experiments conducted at n_TOF. [Extracted from the article]

To evaluate the dosimetric performance of indigenously developed 106Ru-106Rh ophthalmic plaques for treatment of eye cancer, utilizing Monte Carlo simulation, a custom-built phantom, radiochromic films, and diode detectors. 106Ru/106Rh round type eye plaques has been developed from recovered fission product 106Ru, by Bhabha Atomic Research Centre (BARC), India, to treat retinoblastoma and choroidal melanoma. The plaque is made up of three silver layers of purity 99.9%, namely, a 15.8 mm diameter and 0.9 mm thick backing plate, a 13.3 mm diameter and 0.2 mm thick silver substrate that contains 106Ru, and a 0.1 mm thick silver window. The assembly is spherically shaped with a radius of 12 mm and sealed in a controlled environment during the production process. For dosimetry of the plaques, sources with less than 20% non-uniformity in activity distribution were considered. The dosimetry was carried out using Monte Carlo simulation, a custom-built phantom, radiochromic films, and diode detector. In order to validate the accuracy of the dosimetry methodology, dosimetry parameters for a BEBIG CCA type eye plaque (Eckert & Ziegler BEBIG, Berlin, Germany), were generated and compared. The non-uniformity of the activity distribution within the plaque was determined to be within 14%. The absorbed dose rates to water on the central axis at depths of 1 mm and 2 mm were measured as 138.32 mGy/min and 106.26 mGy/min, respectively, with an extrapolated dose at zero depth of 170.70 mGy/min. For BEBIG CCA, these values were found to be 6.8%, 135.32 mGy/min, 103.74 mGy/min, and 172.50 mGy/min, respectively. Monte Carlo simulated and measured percentage depth dose values exhibit good agreement with each other. Additionally, the measured dose rate for the BARC eye plaque closely aligns with the recommended values outlined in the GEC-ESTRO guidelines. The dosimetry of the indigenously developed 106Ru-106Rh eye plaque was carried out using indigenously designed and developed eye phantom. A robust dosimetry methodology was formulated and rigorously tested against data obtained from a commercially available eye plaque. This cost-effective ophthalmic plaque can be a promising asset in the field of ocular oncology, offering the potential for highly efficient and targeted treatments while minimizing potential harm to healthy ocular structures. [ABSTRACT FROM AUTHOR]

This article proposes a practical guide including good laboratory practices followed by a critical review about the application of isotope dilution mass spectrometry (ID-MS) measurement to radionuclide analyses. Several national and international scientific institutions (French Alternative Energies and Atomic Energy Commission, French Radioprotection and Nuclear Safety Institute, European Commission, International Atomic Energy Agency, and Belgian Nuclear Research Centre) participated in this review by sharing their good laboratory practices. ID-MS is one of the primary ratio methods of measurement in the International System of Units. It can produce highly accurate results, as potential sources of bias can be controlled. Many hints are given to obtain the best performance. In addition, a script written with the open source software Octave is provided to calculate the optimal parameters of the {sample–spike} mixture easily. Radionuclide analysis by ID-MS applies to many different fields (environmental, biological, reference materials, irradiated samples, process control, nuclear safeguards and nuclear forensics). [ABSTRACT FROM AUTHOR]

Extensive nuclear data studies have been carried out over the last 30 years in the context of accelerator-based production of radionuclides, especially at energies below 30 MeV, and the achieved database is fairly good. Yet there are some deficiencies or new needs of data. Those needs are generally associated with new emerging clinical applications of radionuclides, e.g. theranostic approach, bimodal imaging, radioimmuno-therapy, etc. This article gives an overview of on-going nuclear data research utilizing charged-particle accelerators in four directions, namely low-energy region, intermediate energy range, use of the α-particle beam, and utilization of fast neutrons generated at accelerators. Wherever possible, a comparison of experimental data with theoretical estimates is presented and evaluated (standardised) data, if available, are also briefly discussed. [ABSTRACT FROM AUTHOR]

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, we study the influence of densified microsilica and colloidal nanosilica admixtures on the mechanical strength and the microstructural characteristics of special mortars used for immobilizing radioactive concrete waste. The experimental program focused on the replacement of cement with micro- and/or nanosilica, in different proportions, in the basic composition of a mortar made with recycled aggregates. The technical criteria imposed for such cementitious systems, used for the encapsulation of low-level radioactive waste, imply high fluidity, increased mechanical strength and lack of segregation and of bleeding. We aimed to increase the structural compactness of the mortars by adding micro- and nanosilica, all the while maintaining the technical criteria imposed, to obtain a cement matrix with high durability and increased capacity for immobilizing radionuclides. The samples from all the compositions obtained were analyzed from the point of view of mechanical strength. Also, micro- and nanosilica as well as samples of the optimal mortar compositions were analyzed physically and microstructurally. Experimental data showed that the mortar samples present maximum compressive strength for a content between 6 and 7.5% wt. of microsilica, respectively, for a content of 2.25% wt. nanosilica. The obtained results suggest a synergistic effect of micro- and nanosilica when they are used simultaneously in cementitious compositions. Thus, among the analyzed compositional variants, the mortar composition with 3% wt. microsilica and 2.25% wt. nanosilica showed the best performance, with an increase in compressive strength of 23.5% compared to the control sample (without micro- and nanosilica). Brunauer–Emmett–Teller (BET) analysis and scanning electron microscopy (SEM) images highlighted the decrease in pore diameter and the increase in structural compactness, especially for mortar samples with nanosilica content or a mixture of micro- and nanosilica. This study is useful in the field of recycling radioactive concrete resulting from the decommissioning of nuclear research or nuclear power reactors. [ABSTRACT FROM AUTHOR]

This special issue of the European Physical Journal: Special Topics focuses on the study of nuclear isomers, which are long-lived excited states of atomic nuclei that can store significant amounts of energy. The issue covers various topics related to nuclear isomerism, including theoretical origins, decay mechanisms, and their role in understanding shell evolution and symmetries in nuclei. The preface highlights the importance of studying isomer physics and mentions potential applications in energy storage, nuclear photonics, and nuclear medicine. The authors express gratitude to the contributors and funding agencies that supported the publication of the special issue. [Extracted from the article]

Nuclear isomers, the excited meta-stable states of nuclei, offer profound insights into nuclear structure. This article reviews the intersection of nuclear isomer research with mass spectrometry methodologies, particularly focusing on novel capabilities of the multiple-reflection time-of-flight mass spectrometry (MR-TOF-MS) technique. Through a comprehensive examination of established methods for isomer identification and characterization, alongside the technical principles underlying MR-TOF-MS, this review discusses the pivotal role of mass spectrometry in advancing our understanding of nuclear isomers. The operational principles and recent developments in MR-TOF-MS technology are explained and exemplified through case studies from prominent research facilities. Furthermore, this work discusses ongoing efforts to enhance sensitivity, resolution, and measurement capabilities in MR-TOF-MS, promising continued advancements in nuclear physics research and applications. [ABSTRACT FROM AUTHOR]

The study of nuclear isomer properties and the isomer applications is a current research focus of nuclear physics and nuclear astrophysics. Theoretical description of nuclear isomers, the surrounding states, and the interplay of them becomes an important issue. In this article, we present the projected shell model method for describing excited nuclear states in general, and for treating K-isomers in particular. With some examples, we emphasize how to apply the modern nuclear many-body technique to calculate K-isomers and normal excited states on an equal footing. [ABSTRACT FROM AUTHOR]

Determining the source location and release rate are critical tasks when assessing the environmental consequences of atmospheric radionuclide releases, but they remain challenging because of the huge multi-dimensional solution space. We propose a spatiotemporally separated two-step framework that reduces the dimension of the solution space in each step and improves the source reconstruction accuracy. The separation process applies a temporal sliding-window average filter to the observations, thereby reducing the influence of temporal variations in the release rate on the observations and ensuring that the features of the filtered data are dominated by the source location. A machine-learning model is trained to link these features to the source location, enabling independent source-location estimations. The release rate is then determined using the projected alternating minimization with L1 norm and total variation regularization algorithm. This method is validated against the local-scale SCK CEN (Belgian Nuclear Research Centre) 41Ar field experiment and the first release of the continental-scale European Tracer Experiment, for which the lowest source-location errors are 4.52 m and 5.19 km , respectively. This presents higher accuracy and a smaller uncertainty range than the correlation-based and Bayesian methods when estimating the source location. The temporal variations in release rates are accurately reconstructed, and the mean relative errors in the total release are 65.09 % and 72.14 % lower than the Bayesian method for the SCK CEN experiment and the European Tracer Experiment, respectively. A sensitivity study demonstrates the robustness of the proposed method to different hyperparameters. With an appropriate site layout, low error levels can be achieved from only a single observation site or under meteorological errors. [ABSTRACT FROM AUTHOR]

Nuclear reactor control is pivotal for the safe and efficient operation of nuclear power plants, facilitating the regulation of reactor reactivity. This study introduces an optimized fractional-order proportional-integral-derivative (FOPID) controller tailored for maintaining reactivity levels in nuclear power plants, particularly during load-following operations. The controller adjusts the position of control rod to regulate power output effectively. We enhance FOPID controller's performance using a modification of Planet Optimization Algorithm (POA-M), leveraging the strengths of the Arithmetic Optimization Algorithm (AOA) to improve its exploitation capabilities. We evaluate the efficacy of POA-M-FOPID controller against traditional techniques, including POA, AOA, and Particle Swarm Optimization (PSO). We assess its performance using the Egyptian Testing Research Reactor (ETRR-2) as a case study. Our results demonstrate that the POA-M-FOPID controller outperforms alternative algorithms across various control metrics, exhibiting superior resilience and efficiency. Notably, the utilization of the POA-M-FOPID controller yields remarkable improvements in reactor power performance, achieving significantly reduced settling time (25.27 sec) and maximum overshoot (0.67 %) compared to conventional FOPID controllers incorporating POA, AOA, and PSO methods. These findings underscore the effectiveness of POA-M-FOPID in enhancing nuclear reactor control systems, offering potential benefits for broader nuclear power industry in terms of safety, stability, and operational efficiency. [ABSTRACT FROM AUTHOR]

To study the dependence of the equation of state of high-density nuclear matter on the term characterizing the isospin (proton–neutron) asymmetry of nuclear matter, it is necessary to measure azimuthal flow of neutrons as well as azimuthal flow of charged particles from a dense nuclear matter in the nuclear–nuclear collisions. For this purpose, the Institute for Nuclear Research (Russian Academy of Sciences) is developing a new high-granular neutron detector that will be used in the BM@N experiment at the extracted beam of the Nuclotron accelerator at the Joint Institute for Nuclear Research (JINR, Dubna). This detector will identify neutrons and measure their energies in the heavy-ion collisions up to 4 GeV per nucleon. This article presents the results of measurements of the time resolution and light yields of samples of scintillation detectors with sizes 40 × 40 × 25 mm3 that will be used in a neutron detector based on the currently available fast plastic scintillator manufactured by JINR using an EQR15 11-6060D-S photodetector for light readout. For comparison, the results of measurements for a detector of the same size with a EJ-230 fast scintillator and with the same type of photodetector are given. The measurements were made on cosmic muons as well as on the Pakhra electron synchrotron of the Lebedev Physical Institute of the Russian Academy of Sciences located in Troitsk, Moscow. [ABSTRACT FROM AUTHOR]

The idea of using nuclear weapons to kill noncombatants is said to evoke strong moral opprobrium among millions of individuals across the globe, such that national leaders should be constrained from using the weapons even when such a decision would be strategically sensible. Classical area scholarship and recent survey evidence suggest that this "nuclear taboo" is strong among the Chinese public, buttressed by culturally grounded preferences for moderation in warfare. Drawing on findings in cultural sociology and political behavior, we argue that previous studies mislead on the extent to which ordinary Chinese citizens might oppose the use of nuclear weapons in a real military clash, primarily due to a failure to distinguish baseline preferences for nuclear nonuse from the willingness to approve of governmental decisions to use these weapons. Results from an original survey experiment fielded in mainland China show that many individuals who personally dislike the idea of using nuclear weapons are nonetheless willing to support their leaders' decision to do so. Our study contributes new and systematic knowledge about Chinese nuclear attitudes and highlights the value of harnessing interdisciplinary insights to inform the research agenda on the nuclear taboo. [ABSTRACT FROM AUTHOR]

The research paradigm in physics has evolved through three distinct phases: empirical observation and induction, theoretical modeling and deduction and computational numerical analysis and simulation. We are now situated within a novel epoch wherein the scientific research paradigm is increasingly shaped by the preeminence of large-scale data and artificial intelligence, particularly within the realm of AI for science applications. The advent of high-energy colliders coupled with Monte Carlo simulations has given rise to an unprecedented accumulation of data. Nested within this transformative research paradigm, machine learning and artificial intelligence technologies have been extensively harnessed for the analysis of these vast data sets. Within the domain of high-energy nuclear physics, two prevalent machine learning techniques have emerged: Bayesian analysis and deep learning. The former employs comprehensive fitting methodologies that compare extensive data sets against theoretical models, enabling the extraction of critical information pertaining to the initial nuclear structure, parton distributions, the equation of state governing hot and dense nuclear matter, and the transport coefficients of the quark–gluon plasma, among other parameters. Conversely, the latter capitalizes on the unparalleled pattern recognition capabilities of deep learning to discern robust features from high-dimensional raw data, specifically targeting individual physical parameters. This paper elucidates the fundamental principles of machine learning and delineates its potential to augment high-energy nuclear physics research endeavors. [ABSTRACT FROM AUTHOR]

The present work deals with diffusion of gases in fully saturated porous media. We test and validate the gas transport mechanism of dissolution and diffusion, implemented in the TH2M process class in the open-source finite-element software OpenGeoSys. We discuss the importance of gas diffusion for the integrity of the multi-barrier system. Furthermore, we present a multi-component mass balance equation implementation in Python, which serves as a reference for the two-component TH2M implementation and allows for a discussion of multi-component gas diffusion in liquids. We verify and validate the numerical implementations as follows: First, we come up with a set of numerical benchmarks in which solutions obtained by the two-component TH2M and multi-component implementations are compared. Thus, we show under which conditions predictions made by the TH2M model can be used for multi-component gas systems. Finally, the work is validated using a through diffusion experiment performed at Belgium's Nuclear Research Centre SCK CEN and a sensitivity analysis is conducted based on the featured experiment. The results of this work illustrate that predictions by both the two- and four-component models match the laboratory findings very well. Therefore, we conclude that also the two-component implementation can reflect the multi-component processes well under the given constraints such as full saturation. Highlights: Numerical modelling of a laboratory scale gas diffusion experiment using Boom Clay samples. Validation of numerical implementation by comparison of experimental and numerical results. Extension of a two-component two-phase flow model towards a multi-component model including comparison of the two implementations. Sensitivity analysis identifies and quantifies the influence of key diffusion parameters, such as the Henry coefficient and diffusivity. [ABSTRACT FROM AUTHOR]

The nuclear dd-fusion reaction can proceed by three possible channels: , , . Interest in dd-fusion has been aroused by both fundamental research and astrophysics and applied science, particularly in the field of fusion reactor development. In the 1970s, the idea of studying the nuclear dd-fusion reaction using polarized deuteron beams was proposed at the Kurchatov Institute. The development of this idea was continued in the PolFusion (polarized fusion) nuclear physics experiment, which aims at studying the reaction of nuclear dd synthesis with polarized source particles in the low energy region. The experiment is planned to measured the scattering asymmetries of dd-fusion reaction products in the final state at different mutual orientation of the spins of colliding deuterons in the energy range 10–100 keV. The authors present an overview of the status of the experiment. [ABSTRACT FROM AUTHOR]

In introductory physics labs, a challenge arises when students are asked to measure a well-known quantity, such as the free fall acceleration, g. Students often don't perform a proper error analysis if they already know the correct answer, and their result is "close enough." Masking, or disguising the correct answer, as is often done in nuclear and particle physics research, encourages students to be more careful. In this paper, we introduce a new unit of measurement; in these units, students don't know what the value of g should be, leading to a more engaging and authentic scientific experience. Additionally, we instituted a mock "conference" in which students settled on a consensus value of g in this new system of units. When students quantitatively compare their measurements of an unknown quantity, it motivates them to perform a detailed error analysis. Student feedback on this reformed lab was largely positive. Experimental research in physics often involves repeated measurements of an unknown quantity by different groups. Ultimately (after careful analysis and comparison of results), a scientific consensus can be reached. This process often differs from a traditional undergraduate lab experience, where students might already know the result and simply aim to confirm it. In this article, the authors describe one way to make the lab experience more scientifically authentic: by developing special measuring devices which employ a newly created, nonstandard system of units. This article will be of interest to readers who would like to develop curricula which foster scientific reasoning and research skills. [ABSTRACT FROM AUTHOR]

The purpose of this study is to provide a new deterministic model for the SLOWPOKE-2 nuclear research reactor at École Polytechnique de Montréal (EPM) with LEU (Low Enriched Uranium) core. Using the latest release of the code system DRAGON5 and DONJON5 and the cross-section data library ENDFB.VII rel.1 evaluation, the developed model is applied to simulate the neutronic behavior of the SLOWPOKE-2 research reactor. We studied the separate temperature effects of the main components of the core (i.e., fuel, coolant/moderator, beryllium reflector, and water reflector). The contribution of different physical phenomena to the RTC was assessed. The temperature reactivity feedback calculated using the deterministic approach based on the DRAGON5 and DONJON5 code system using the ENDF/B-VII.1 evaluated nuclear data library produced in the WIMD-D4 format is in good agreement. Therefore, this work proves the capability of DRAGON5 and DONJON5 codes, normally used for power reactors, to reliably simulate a low-power research reactor. [ABSTRACT FROM AUTHOR]

The editorial in "Frontiers in Physics" discusses the historical significance of nuclear physics and its impact on scientific progress, technological advancements, and medical applications. It highlights the emergence of high-intensity lasers as a new tool for exploring nuclear processes and outlines the challenges and opportunities in laser-driven nuclear physics research. The editorial introduces a Research Topic comprising 18 research papers from prestigious institutions worldwide, focusing on experimental and theoretical aspects of laser-driven nuclear reactions, advanced particle sources, and computational methods for nuclear physics. The papers cover a wide range of topics, including fusion experiments, particle acceleration, and nuclear excitation studies, showcasing the interdisciplinary nature of the field and its potential for practical applications. [Extracted from the article]

Initially, the growth of particle detectors was focused on the identification of particles, but new detector designs have made it possible to build new diagnostic techniques. Clinical settings and medical research facilities utilize cutting-edge methods developed from particle accelerators, detectors, and physics computers, including imaging technologies, accelerators specifically designed for cancer therapy, simulations, data analysis, and nuclear medicine. It is still obvious that research in nuclear and basic particle physics is what motivates and propels the development of particle detectors for medical applications. The applications of the particle physics detector in medical science will be the main topic of this paper. [ABSTRACT FROM AUTHOR]

A major concern for nuclear research reactors under normal operating conditions is that they may release radioactive elements into the atmosphere, endangering public health and the environment. The present study concentrated on the detailed radiological dose assessment resulting from the atmospheric release of 41Ar activity from the TRIGA Mark‐II research reactor in Bangladesh during its normal operational condition at full power of 3 MW. The total effective dose equivalent (TEDE), ground deposition activity, organ‐committed dose, and pathways dose values have been evaluated under different weather conditions using the HotSpot 3.1.2 code. The weather data have been gathered from the Bangladesh Meteorological Department (BMD), Dhaka. Two significant seasons with various weather stability effects have been considered for dose analysis. Atmospheric dispersion of 41Ar was evaluated using the Gaussian plume model. From the obtained results, the maximum TEDE of 4.06 × 10−9 Sv at 0.19 km distance from the reactor site for stability class B during the summer season is found to be well below the annual effective dose limit of 1 mSv recommended by the ICRP. During the rainy season, the maximum TEDE of 1.76 × 10−9 Sv at 0.92 km distance for stability class E is also found to be negligible compared to the dose limit. From the organ‐committed dose analysis, skin is investigated as the highest dose absorber compared to other organs. The pathways dose analysis concludes that the submersion and ground shine doses are observed to be maximum at 0.20 km and 1.0 km distances for the summer and rainy seasons, respectively. Based on the identified results, dose values have been found to be within the limiting values, ensuring environmental and human health safety. Such comprehensive dose analysis due to the atmospheric release of 41Ar activity is very significant from the perspective of ensuring the radiological and environmental safety of research‐type nuclear reactors under normal operational conditions. [ABSTRACT FROM AUTHOR]

Tokamak is an important device for controlled nuclear fusion research. The plasma electronic density control system (PEDCS) is an important system for controlling the Tokamak discharge process, which should be of high stability, rapidity, and accuracy. Gas seeding systems are widely used in many Tokamak devices to achieve plasma electronic density control. According to the mechanism model analysis for the plasma electronic density object, an adapted single neuron proportion integration differentiation (PID) control algorithm with the radial basis function (RBF) neural network tuning is studied. The principle and the implementation of the intelligent control algorithm are described in detail in this paper. The intelligent controller enables the system to optimize the PID parameters online according to the density state in the discharge process. The experimental results show that the adapted algorithm achieves a good control effect and also improves the control performance. The proposed method provides a useful reference for Tokamak devices and other similar control systems. [ABSTRACT FROM AUTHOR]

A review on the research contributions from the nuclear and particle physics laboratory of Rajshahi University is presented. Special emphasis has been given to the nuclear physics research using the molecular nucleus-nucleus (NN) potentials derived from the Pauli-laden energy density functional (EDF) theory. The successes of EDF-derived non-monotonic (NM) NN potentials, compared to other familiar optical model potentials such as Woods-Saxon (WS), Squared Woods-Saxon (SWS), double folding (DF) for NN interactions, have been discussed. The phenomenal successes of NM potentials with a repulsive core have been found to suggest that the true nature of NN potential is NM with the Pauli-compliant EDF as its root. [ABSTRACT FROM AUTHOR]

Autonomous nuclear reactor monitoring is a key aspect of the International Atomic Energy Agency's strategy to ensure nonproliferation treaty compliance. From the rise of small modular reactor technology, decentralized nuclear reactor fleets may strain the capacities of such monitoring and requires new approaches. We demonstrate the superior capabilities of a gamma detection system to monitor the criticality of a zero power nuclear reactor from beyond typical vessel boundaries, offering a powerful alternative to neutron-based systems by providing direct information on fission chain propagation. Using the case example of the research reactor CROCUS, we demonstrate how two bismuth germanate scintillators placed outside the reactor vessel can precisely observe reactor criticality using so called noise methods and provide core status information in seconds. Our results indicate a wide range of applications due to the newly gained geometric flexibility that could find use in fields beyond nuclear safety. [ABSTRACT FROM AUTHOR]