Nuclear Reactions Research Articles

Nonlinear-optical analogies in nuclear-like soliton reactions: selection rules, nonlinear tunneling and sub-barrier fusion-fission

Abstract The main goal of our article is to reveal unexpected but intriguing analogies arising between optical solitons and nuclear physics, which still remain hidden from us. We consider the main cornerstones of the concept of nonlinear optics of nuclear reactions and the well-dressed repulsive-core solitons. On the base of this model, we reveal the most intriguing properties of the nonlinear tunneling of nucleus-like solitons and the soliton selfinduced sub-barrier transparency effect. We describe novel interesting and stimulating analogies between the interaction of nucleus-like solitons on the repulsive barrier and nuclear sub-barrier reactions. The main finding of our study concerns the conservation of total number of nucleons (or the baryon number) in nuclear-like soliton reactions. We show that inelastic interactions among well-dressed repulsive-core solitons arise only when a “cloud” of “dressing” spectral side-bands appears in the frequency spectra of the solitons. This property of nucleus-like solitons is directly related to the nuclear density distribution described by the dimensionless small shape-squareness parameter. Thus the Fourier spectra of nucleus-like solitons are similar to the nuclear form factors. We show that the nuclear-like reactions between well-dressed solitons are realized by “exchange” between “particle-like” side-bands in their spectra.

Nonlinear-optical analogies in nuclear-like soliton reactions: selection rules, nonlinear tunneling and sub-barrier fusion-fission

Abstract The main goal of our article is to reveal unexpected but intriguing analogies arising between optical solitons and nuclear physics, which still remain hidden from us. We consider the main cornerstones of the concept of nonlinear optics of nuclear reactions and the well-dressed repulsive-core solitons. On the base of this model, we reveal the most intriguing properties of the nonlinear tunneling of nucleus-like solitons and the soliton selfinduced sub-barrier transparency effect. We describe novel interesting and stimulating analogies between the interaction of nucleus-like solitons on the repulsive barrier and nuclear sub-barrier reactions. The main finding of our study concerns the conservation of total number of nucleons (or the baryon number) in nuclear-like soliton reactions. We show that inelastic interactions among well-dressed repulsive-core solitons arise only when a “cloud” of “dressing” spectral side-bands appears in the frequency spectra of the solitons. This property of nucleus-like solitons is directly related to the nuclear density distribution described by the dimensionless small shape-squareness parameter. Thus the Fourier spectra of nucleus-like solitons are similar to the nuclear form factors. We show that the nuclear-like reactions between well-dressed solitons are realized by “exchange” between “particle-like” side-bands in their spectra.

New Version of the Experimental Setup for the Measurement of γ-Quantum Emission Cross Sections in Nuclear Reactions Induced by 14.1 MeV Neutrons

Within the TANGRA project framework, a new experimental setup has been constructed for the measurement of reaction cross sections (n, X, γ) in the interaction of 14.1 MeV neutrons with nuclei. The facility has a special feature: the use of the tagged neutron method. This method enables efficient separation of background and useful events, as well as accurate tracking of neutron flux. Test measurements were performed on 28Si, 12C, and 16O nuclei, and the results showed satisfactory agreement with available experimental data. This paper presents the features of the setup design and the methodology for processing the obtained experimental data

New Version of the Experimental Setup for the Measurement of γ-Quantum Emission Cross Sections in Nuclear Reactions Induced by 14.1 MeV Neutrons

Within the TANGRA project framework, a new experimental setup has been constructed for the measurement of reaction cross sections (n, X, γ) in the interaction of 14.1 MeV neutrons with nuclei. The facility has a special feature: the use of the tagged neutron method. This method enables efficient separation of background and useful events, as well as accurate tracking of neutron flux. Test measurements were performed on 28Si, 12C, and 16O nuclei, and the results showed satisfactory agreement with available experimental data. This paper presents the features of the setup design and the methodology for processing the obtained experimental data

Evaluation of sodium borocaptate (BSH) and boronophenylalanine (BPA) as boron delivery agents for neutron capture therapy (NCT) of cancer: an update and a guide for the future clinical evaluation of new boron delivery agents for NCT.

Boron neutron capture therapy (BNCT) is a cancer treatment modality based on the nuclear capture and fission reactions that occur when boron-10, a stable isotope, is irradiated with neutrons of the appropriate energy to produce boron-11 in an unstable form, which undergoes instantaneous nuclear fission to produce high-energy, tumoricidal alpha particles. The primary purpose of this review is to provide an update on the first drug used clinically, sodium borocaptate (BSH), by the Japanese neurosurgeon Hiroshi Hatanaka to treat patients with brain tumors and the second drug, boronophenylalanine (BPA), which first was used clinically by the Japanese dermatologist Yutaka Mishima to treat patients with cutaneous melanomas. Subsequently, BPA has become the primary drug used as a boron delivery agent to treat patients with several types of cancers, specifically brain tumors and recurrent tumors of the head and neck region. The focus of this review will be on the initial studies that were carried out to define the pharmacokinetics and pharmacodynamics of BSH and BPA and their biodistribution in tumor and normal tissues following administration to patients with high-grade gliomas and their subsequent clinical use to treat patients with high-grade gliomas. First, we will summarize the studies that were carried out in Japan with BSH and subsequently at our own institution, The Ohio State University, and those of several other groups. Second, we will describe studies carried out in Japan with BPA and then in the United States that have led to its use as the primary drug that is being used clinically for BNCT. Third, although there have been intense efforts to develop new and better boron delivery agents for BNCT, none of these have yet been evaluated clinically. The present report will provide a guide to the future clinical evaluation of new boron delivery agents prior to their clinical use for BNCT.

Slow 7Be and the primordial 7Li abundance

The cross sections of neutron-induced nuclear reactions are commonly large at low energies. Given this feature, the 7Be(n, p)7Li process with slow 7Be is studied in connection with the cosmological lithium problem. An idea is tested whether slow (non-Maxwellian) 7Be born in the radiative capture 3He(α, γ)7Be reaction can boost the 7Be(n, p)7Li(p, α)α mechanism of 7Li burn-up in the early universe, reducing the amount of primordial 7Li. The rate of this sequential process is examined and its effect on the 7Li abundance is clarified. In the absence of 7Be thermalization in the primordial plasma, the above mechanism can decrease 7Li/H by several percent, leaving unchanged the abundances of D and 4He which are consistent with observations. However, taking into account the 7Be thermalization due to scattering off electrons, positrons, nuclei, and photons radically suppresses the effect. It is found that the typical thermalization time of 7Be is less than 10−5 s, while the fraction of non-Maxwellian particles in the 7Be component is at most 2 × 10−7. Under this condition, the corresponding impact on 7Li/H is estimated to be no more than 10−5%.

Effect of Microstructure on Oxidation and Micro-mechanical Behavior of Arc Consolidated Mo-Ti-Si-(B) Alloys

AbstractThe present study deals with the development and characterization of Mo-35Ti-10Si and Mo-35Ti-10Si-2B (wt.%) alloy for ultra-high temperature applications beyond the temperature limit of existing super alloys. The microstructural characterization using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), electron back scattered diffraction (EBSD), x-ray diffraction (XRD) revealed that the Mo-35Ti-10Si-2B alloy was consisted of three phases, namely, (Mo, Ti)ss, (Mo, Ti)5SiB2 and (Ti, Mo)5Si3; whereas, Mo-35Ti-10Si alloy was found to be consisting of (Mo, Ti)ss, and (Mo,Ti)3Si phases. Since quantification of boron is difficult by EDS, Particle Induced Gamma-ray Emission (PIGE), a nuclear reaction analysis technique was used for chemical composition analysis of boron. The oxidation behavior of the Mo-35Ti-10Si-2B alloy in the temperature regime of 825-1250 °C was studied in detail and compared with boron-free Mo-35Ti-10Si alloy. Mo-35Ti-10Si-2B alloy exhibited superior oxidation behavior at intermediate temperatures of 825 °C, and excellent oxidation resistance at higher temperatures between 1000 and 1250 °C due to the formation of the protective borosilica and double oxide layers (TiO2 and duplex borosilica-TiO2), respectively. High-temperature oxidation mechanisms were discussed using detailed microstructural cross section analysis of the oxidized alloy samples. The micro-mechanical behavior of constitutive phases of the Mo-35Ti-10Si-2B alloy were studied by microhardness, nano-indentation and micropillar compression testing. The micropillar compression of (Mo, Ti)ss phase showed fairly ductile behavior with the evidence of activation of dislocation in the form of slip lines revealed through the post-deformation fractography. Deformation studies of (Mo, Ti)5SiB2 and (Ti, Mo)5Si3 phases were also carried out which showed large strain bursts indicating possibility of activation of dislocation activities even at room temperatures imparting low level of ductility.

Effect of Microstructure on Oxidation and Micro-mechanical Behavior of Arc Consolidated Mo-Ti-Si-(B) Alloys

AbstractThe present study deals with the development and characterization of Mo-35Ti-10Si and Mo-35Ti-10Si-2B (wt.%) alloy for ultra-high temperature applications beyond the temperature limit of existing super alloys. The microstructural characterization using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), electron back scattered diffraction (EBSD), x-ray diffraction (XRD) revealed that the Mo-35Ti-10Si-2B alloy was consisted of three phases, namely, (Mo, Ti)ss, (Mo, Ti)5SiB2 and (Ti, Mo)5Si3; whereas, Mo-35Ti-10Si alloy was found to be consisting of (Mo, Ti)ss, and (Mo,Ti)3Si phases. Since quantification of boron is difficult by EDS, Particle Induced Gamma-ray Emission (PIGE), a nuclear reaction analysis technique was used for chemical composition analysis of boron. The oxidation behavior of the Mo-35Ti-10Si-2B alloy in the temperature regime of 825-1250 °C was studied in detail and compared with boron-free Mo-35Ti-10Si alloy. Mo-35Ti-10Si-2B alloy exhibited superior oxidation behavior at intermediate temperatures of 825 °C, and excellent oxidation resistance at higher temperatures between 1000 and 1250 °C due to the formation of the protective borosilica and double oxide layers (TiO2 and duplex borosilica-TiO2), respectively. High-temperature oxidation mechanisms were discussed using detailed microstructural cross section analysis of the oxidized alloy samples. The micro-mechanical behavior of constitutive phases of the Mo-35Ti-10Si-2B alloy were studied by microhardness, nano-indentation and micropillar compression testing. The micropillar compression of (Mo, Ti)ss phase showed fairly ductile behavior with the evidence of activation of dislocation in the form of slip lines revealed through the post-deformation fractography. Deformation studies of (Mo, Ti)5SiB2 and (Ti, Mo)5Si3 phases were also carried out which showed large strain bursts indicating possibility of activation of dislocation activities even at room temperatures imparting low level of ductility.

Technological Novelties and Scientific Discoveries with the Borexino Experiment

The Borexino experiment has developed, in its 32 years of activity, techniques and methods that allow for unprecedented radiopurity levels, which continue to be the current state of the art. These pioneering techniques and methods represent a new standard for ultra-low-background physics, a legacy that Borexino leaves to future experiments studying low-energy neutrinos and searching for rare events with detectors operating deep underground. The Borexino experiment leaves an equally influential scientific legacy with its discoveries and precise measurements of the nuclear processes that cause the Sun and stars to shine. Thanks to its unparalleled low background in the energy window of ∼150 keV to ∼15 MeV, the Borexino experiment also has contributed significantly to the understanding of neutrino oscillations with the observation of the energy-dependent matter to vacuum-dominated flavor conversion probability of solar neutrinos. Along with this textbook-quality body of solar neutrino results, the Borexino experiment has contributed to the study of the Earth's mantle radioactivity with background-free measurements of geoneutrinos. This article presents an overview of the long-lasting Borexino results and of the experimental efforts required to achieve them.

Technological Novelties and Scientific Discoveries with the Borexino Experiment

The Borexino experiment has developed, in its 32 years of activity, techniques and methods that allow for unprecedented radiopurity levels, which continue to be the current state of the art. These pioneering techniques and methods represent a new standard for ultra-low-background physics, a legacy that Borexino leaves to future experiments studying low-energy neutrinos and searching for rare events with detectors operating deep underground. The Borexino experiment leaves an equally influential scientific legacy with its discoveries and precise measurements of the nuclear processes that cause the Sun and stars to shine. Thanks to its unparalleled low background in the energy window of ∼150 keV to ∼15 MeV, the Borexino experiment also has contributed significantly to the understanding of neutrino oscillations with the observation of the energy-dependent matter to vacuum-dominated flavor conversion probability of solar neutrinos. Along with this textbook-quality body of solar neutrino results, the Borexino experiment has contributed to the study of the Earth's mantle radioactivity with background-free measurements of geoneutrinos. This article presents an overview of the long-lasting Borexino results and of the experimental efforts required to achieve them.

China's nuclear power in the context of decarbonization of the global energy industry

The global structure of energy resource consumption is analyzed. It is shown that the total consumption of energy resources in the 20th century increased almost 15 times and amounted to about 118 PWh in 2000. Of these, more than 80% were fossil (natural) energy carriers, 13 % were renewable energy sources and more than 6 % were nuclear power. This trend has continued for many years. Renewable energy sources and nuclear power are projected to dominate the growth of global energy consumption, meeting on average more than 90 % of the additional demand. China ranks first in the world in terms of GDP and the rate of development of the electric power complex, as well as in terms of production volume and the rate of development of nuclear power. The structure of electricity generation by fuel type in countries (TOP 5, 2021) with high energy consumption has been analyzed. It is shown that the main players in this market are three countries: China (30 %), USA (13 %) and India (6 %). The volume of electricity production in China is almost three times larger than in the EU countries and almost 7 times larger than in Russia. The structure of nuclear energy and China's achievements in this field are considered. It is shown that in the context of nuclear technologies (creation of fourth-generation reactors, development of technologies close to the full closed cycle of nuclear waste processing) China is already ready to significantly expand the scope of nuclear energy. Special attention is paid to the safety of nuclear facilities operations. The main problem China will face is the absence of an insurmountable barrier between civilian and military use of such technologies. This poses a serious threat to the ecology and life safety of the country. In the long term, nuclear power must also solve the problem of safe, long-term disposal of radioactive waste. It is shown that in the future China needs to re-examine its nuclear program in the context of cooperation with International Nuclear Security Organizations.

DEM Simulation of the Idaho Calcine Simulant for Hot Isostatic Pressing Canister Filling Process: Part 2

This paper introduces a novel approach to the bulk material handling of simulated radioactive material, focusing on the challenging Idaho calcine waste. Due to the limited availability of the simulant, virtual dynamic simulations were utilized to develop technology demonstration−scale models to assess the efficacy of the discrete element method (DEM) for process development studies. The DEM model was validated using historical experimental data, demonstrating its feasibility with affordable hardware. Acknowledging the limitations of computational analysis, the presented contact model is deemed adequate for preliminary engineering studies. This research advances bulk material handling and provides valuable insights for nuclear waste treatment processes, offering a pioneering framework for researchers working with the Idaho calcine simulant.

Multiple types of nuclear localization signals in Entamoeba histolytica

Entamoeba histolytica is a protozoan parasite that belongs to the Amoebozoa supergroup whose study related to the nucleocytoplasmic transport of proteins through the nucleus is poorly studied. In this work, we have performed in silico predictions of the potential nuclear localization signals (NLS) corresponding to the proteome of 8201 proteins from Entamoeba histolytica annotated in the AmoebaDB database. We have found the presence of monopartite nuclear localization signals (MNLSs), bipartite nuclear localization signals (BNLSs), and non-canonical monopartite NLSs with lengths exceeding 20 amino acid residues. Additionally, we detected a new type of NLS consisting of multiple juxtaposed bipartite NLSs (JNLSs) that have not been described in any eukaryotic organism. Also, we have generated consensus sequences for the nuclear import of proteins with the NLSs obtained. Docking experiments between EhImportin α and an MNLS, BNLS, and JNLS outlined the interacting residues between the Importin and cargo proteins, emphasizing their putative roles in nuclear import. By transfecting HA-tagged protein constructs, we assessed the nuclear localization of MNLS (U1A and U2AF1), JMNLS (U2AF2), and non-canonical NLS (N-terminus of Pol ll) in vivo. Our data provide the basis for understanding the nuclear transport process in E. histolytica.

Non-Nucleon Metastable Excitations in Nuclear Matter and e– Catalysis As a Quark-Cumulative Mechanism for Initiating Low-Energy Nuclear Chemical Processes: Phenomenology

Non-Nucleon Metastable Excitations in Nuclear Matter and e– Catalysis As a Quark-Cumulative Mechanism for Initiating Low-Energy Nuclear Chemical Processes: Phenomenology

NEBOAS: A Neutron yiElds Based On AcceleratorS application

The web-based application NEBOAS was developed to calculate the neutron yield of the accelerator-based neutron source MONNET (MONo-energetic NEutron Tower) at JRC-Geel. Neutrons are produced with p and d-induced reactions on particular targets. NEBOAS provides double differential neutron yields, as a function of the angle of neutron emission and energy. It provides also integrated neutron yields, and neutron energy spectra. Any projectile energy may be utilized, as long as it is covered by the nuclear data available on thin targets (that just degrade the projectiles' energy) or thick targets (that stop the projectiles). The calculation employs reaction cross-section evaluations from Evaluated Nuclear Data File (ENDF) or compilations of experimental measurements from the Experimental Nuclear Reaction Data (EXFOR), and stopping powers as recommended in the National Institute of Standards and Technology (NIST) or the Stopping and Range of Ions in Matter (SRIM-2013) databases.

Compound nucleus formation probability of heavy and superheavy nuclei synthesized using heavy ion fusion reactions

The role of entrance channel parameters such as Z2/A, charge asymmtery αz, mass-asymmetry (ηA), charge product (Z1Z2), mean fissility χm, Coulomb interaction parameter and (N−Z)/(N+Z) on compound nucleus formation of actinide nuclei using heavy ion fusion reactions were investigated. For the formation of compound nuclei, the considered atomic number range of the projectile varies between 5≤Z≤14 and the mass number lies between 10≤A≤34. Similarly, the studied target atomic number varies between 78≤Z≤92 and the mass number range is 197≤A≤238. Among these entrance channel parameters, PCN is more systematic for (N−Z)(N+Z), Z2/A and αz. In addition to entrance channel parameters, the Ecm and EBass also play a significant role in the prediction of PCN. The proposed empirical formulae are applicable to the compound nuclei from Fr to Sg. These findings are significant for the PCN prediction from Fr to Sg.

Solar Models and Astrophysical S-factors Constrained by Helioseismic Results and Updated Neutrino Fluxes

The ratio of metal abundance to hydrogen abundance of the solar photosphere, (Z/X) s , has been revised several times. Standard solar models, based on these revised solar abundances, are in disagreement with seismically inferred results. Recently, Magg et al. introduced a new value for (Z/X) s , which is still under debate in the community. The solar abundance problem or solar modeling problem remains a topic of ongoing debate. We constructed rotating solar models in accordance with various abundance scales where the effects of convection overshoot and enhanced diffusion were included. Among these models, those utilizing Magg’s abundance scale exhibit superior sound speed and density profiles compared to models using other abundance scales. Additionally, they reproduce the observed frequency separation ratios r 02 and r 13. These models also match the seismically inferred surface helium abundance and convection zone depth within the 1σ level. Furthermore, the calculated neutrino fluxes from these models agree with detected ones at the level of 1σ. We found that neutrino fluxes and density profile are influenced by nuclear reactions, allowing us to use the combination of detected neutrino fluxes and seismically inferred density for diagnosing astrophysical S-factors. This diagnostic approach shows that S 11 may be underestimated by 2%, while S 33 may be overestimated by about 3% in previous determinations. The S-factors favored by updated neutrino fluxes and helioseismic results can lead to significant improvements in solar models.

A rumor propagation model based on nuclear fission

The propagation of online rumors is rapid, and its propagation mechanism has always been a research difficulty. In this paper, the network rumors are compared to the nuclear fission process, and a network rumors propagation model is constructed. First, the initial online rumors are compared to neutrons, uranium nuclei are compared to individual rumor receivers, and fission barriers are compared to individual active propagation thresholds. Second, the process of nuclear fission is analyzed and the degree of energy accumulation is used to compare the social impact of online rumors. Finally, the online rumor propagation model based on nuclear fission is constructed. Through experimental simulation, it has been shown that compared to classic infectious disease models, this model can better describe the propagation process of rumors in social networks. Through research and analysis, suggestions for suppressing rumors have been proposed, providing new ideas and references for future researchers.

A modular, high dynamic range passive neutron dosimeter and imaging diagnostic.

The multi-decade neutron dosimeter and imaging diagnostic (MDND) is a passive diagnostic that utilizes the polyethylene (n, p) nuclear reaction to enhance the diagnostic's sensitivity for time and energy integrated neutron measurements in the range of 2.45-14.1MeV. The MDND utilizes a combination of radiochromic film, phosphor image plates, and solid-state nuclear track detectors, with the goal of providing several orders of magnitude of dynamic range in terms of measured neutron fluence. The diagnostic design was guided by simulations in the Monte Carlo N-Particle (MCNP) transport code to determine the optimum thickness of the polyethylene convertor for maximum proton fluence incident on the detection medium as a function of incident neutron energy. In addition, the simulation results of complete diagnostic assemblies, or "stacks," were used to determine the total dynamic range of an MDND in terms of measured neutron source yield, which was found to be between around 107 and 1015 emitted into 4π with the detector located 1m away from the source. Complimentary to these simulations, individual detectors within a stack were simulated and analyzed to determine response as a function of neutron energy and yield. This work presents the diagnostic design, MCNP simulation results, and analysis of expected signals for varying neutron sources.

Lead-free Ce-doped perovskite scintillators with high figure of merit

Lead halide perovskite scintillators have recently received extensive research attention owing to their short fluorescence lifetimes, low detection limits, and ease of fabrication compared to traditional scintillators. The nontoxic cerium-doped lead-free perovskites with intrinsically efficient and short lifetime d–f transitions are a prospective replacement for the toxic Pb2+. Here, we demonstrated Ce-doped cesium lanthanide chloride perovskites (Cs3LnCl6, Ln=Gd, Y, Lu) synthesized through a facile solution method for the first time. These perovskites exhibit blue-violet emission, which arises from Ce 5d→4f transitions. Among three types of Cs3LnCl6 perovskites, Ce:Cs3LuCl6 exhibited high photoluminescence quantum yield (PLQY) of 82% and a short excited-state lifetime of approximately 34 ns. When utilized as X-ray scintillators, Ce:Cs3LuCl6 crystals display a high light yield of 8120 photons per MeV and a low detection limit of 36.8 nGy air s−1. Importantly, the figure of merit (FoM), representing the ratio of light yield to decay time, reaches 239, which is the highest reported value for lead-free perovskite scintillators up to now. Additionally, the fabrication of perovskite/PMMA films was undertaken for practical demonstrations in X-ray imaging, resulting in the attainment of a resolution of up to 8.38 lp/mm. We anticipate that this work will inspire the utilization of Ce-doped Cs3LnCl6 perovskites in ultrafast scintillation applications such as high-energy physics, nuclear reaction monitoring, and dynamic X-ray imaging.