Nuclear Reactions Research Articles

Excitation functions of (n, p) reactions for the production of iodine isotopes used in medical applications

The cross sections of 124Xe (n, p)124I, 125Xe (n, p)125I, 126Xe (n, p)126I, 128Xe (n, p)128I, 129Xe (n, p)129I, 130Xe (n, p)130I, 131Xe (n, p)131I, 132Xe (n, p)132I, 133Xe (n, p)133I, 134Xe (n, p)134I and 135Xe (n, p)135I for production of iodine isotopes were calculated at neutron energy ranges between 1 and 20 MeV with the help of three computer nuclear codes (EMPIRE 3.2.3, ALICE-ASH and TALYS 1.95). Furthermore, the cross sections were calculated by the empirical formula derived in some previous studies at 14.5 MeV. The previous calculated data from the evaluated data from the Evaluated Nuclear Data File (ENDF), such as ENDF/B-VIII.0; JEFF-3.3; ROSFOND-2010; CENDL-3.2; JENDL-4.0; JENDL-5.0; and TENDL-2021, as well as the experimental nuclear reaction cross-section data (EXFOR) about the above reactions, have been collected. In general, the calculated results by computer codes are in good agreement when compared with earlier empirical formulas, the measured values in the EXFOR library, and the evaluated data (ENDF/B-VIII.0; JEFF-3.3; JENDL-4.0; JENDL-5.0; ROSFOND-2010; CENDL-3.2; and TENDL-2021) with some exceptional.

Investigation of the production routes of 81,82m,83,84 Rb isotopes through proton-induced nuclear reactions on 82,83,84,86 Kr

Investigations using nuclear reaction models are significant and have considerable consequences in terms of understanding nuclear reaction processes and their nature. The nuclear data on radionuclides created by the cyclotron find application in nuclear diagnostics and therapeutic treatments. The excitation function of proton-induced nuclear reactions on 82,83,84,86 Kr for the generation of medically beneficial short-lived radioisotopes 81,82m,83,84 Rb from threshold energy to 50 MeV has been investigated using Koning–Delaroche optical model potential with nuclear level density (NLD) from both the phenomenological and microscopic nuclear models incorporated in TALYS1.96 code. The phenomenological constant temperature + Fermi gas model, back-shifted Fermi gas model, generalised superfluid model, and microscopic NLD from the Skyrme–Hartree–Fock–Bogoliubov, Gogny–Hartree–Fock–Bogoliubov, and temperature-dependent Gogny–Hartree–Fock–Bogoliubov NLD tables have been used to calculate the excitation function. The calculated excitation functions are compared with the experimental data from EXFOR and the TALYS evaluated nuclear data library (TENDL2023). An analysis is carried out by estimating the mean deviation D-value between the theoretical and experimental cross-sections, and the NLD model corresponding to the best result is used for the estimation of activity and production yield for each reaction channel.

Human Serum Albumin-Coated 10B Enriched Carbon Dots as Targeted "Pilot Light" for Boron Neutron Capture Therapy.

Boron neutron capture therapy (BNCT) is a physiologically focused radiation therapy that relies on nuclear capture and fission processes. BNCT is regarded as one of the most promising treatments due to its excellent accuracy, short duration of therapy, and low side effects. The creation of novel boron medicines with high selectivity, ease of delivery, and high boron-effective load is a current research topic. Herein, boron-containing carbon dots (BCDs) and their human serum albumin (HSA) complexes (BCDs-HSA) are designed and synthesized as boron-containing drugs for BNCT. BCDs (10B: 7.1 wt%) and BCDs-HSA exhibited excitation-independent orange fluorescent emission which supported the use of fluorescence imaging for tracking 10B in vivo. The introduction of HSA enabled BCDs-HSA to exhibit good biocompatibility and increased tumor accumulation. The active and passive targeting abilities of BCDs-HSA are explored in detail. Subcutaneous RM-1 tumors and B16-F10 tumors both significantly decrease with BNCT, which consists of injecting BCDs-HSA and then irradiating the area with neutrons. In short, this study provides a novel strategy for the delivery of boron and may broaden the perspectives for the design of boron-containing carbon dots nanomedicine for BNCT.

A transcription-independent role for HIF-1α in modulating microprocessor assembly.

Microprocessor is an essential nuclear complex responsible for the initial RNase-mediated cleavage of primary miRNA, which is a tightly controlled maturation process that requires the proper assembly of Drosha and DGCR8. Unlike previously identified mechanisms directly targeting the enzymatic subunit Drosha, current knowledge about the biological ways of controlling miRNA nuclear maturation through DGCR8 is less addressed. In this study, we unveiled that the microprocessor assembly is governed by a master gene regulator HIF-1α irrespective of its canonical transcriptional activity. First, a widespread protein binding of HIF-1α with DGCR8 instead of Drosha was observed in response to biological stimulations. Similar protein interactions between their corresponding orthologues in model organisms were also observed. After dissecting the essential protein domains, we noticed that HIF-1α suppresses microprocessor assembly via binding to DGCR8. Furthermore, our results showed that HIF-1α hijacks monomeric DGCR8 thus reducing its dimer formation prior to microprocessor assembly, and consequently, the suppressed microprocessor formation and nuclear processing of primary miRNA were demonstrated. In conclusion, here we unveiled the mechanism of how microprocessor assembly is regulated by HIF-1α, which not only demonstrates a non-transcriptional function of nuclear HIF-1α but also provides new molecular insights into the regulation of microprocessor assembly through DGCR8.

Manifestation of relativistic effects in the chemical properties of nihonium and moscovium revealed by gas chromatography studies.

Chemical reactivity of the superheavy elements nihonium (Nh, element 113) and moscovium (Mc, element 115) has been studied by the gas-solid chromatography method using a new combined chromatography and detection setup. The Mc isotope, 288Mc, was produced in the nuclear fusion reaction of 48Ca ions with 243Am targets at the GSI Helmholtzzentrum Darmstadt, Germany. After isolating 288Mc ions in the gas-filled separator TASCA, adsorption of 288Mc and its decay product 284Nh on silicon oxide and gold surfaces was investigated. As a result of this work, the values of the adsorption enthalpy of Nh and Mc on the silicon oxide surface were determined for the first time, kJ/mol and kJ/mol (68% c.i.). The obtained -ΔH ads values are in good agreement with results of advanced relativistic calculations. Both elements, Nh and Mc, were shown to interact more weakly with the silicon oxide surface than their lighter homologues Tl and Bi, respectively. However, Nh and Mc turned out to be more reactive than the neighbouring closed-shell and quasi-closed-shell elements copernicium (Cn, element 112) and flerovium (Fl, element 114), respectively. The established trend is explained by the influence of strong relativistic effects on the valence atomic orbitals of these elements.

Toward a Comprehensive Grid of Cepheid Models with MESA. I. Uncertainties of the Evolutionary Tracks of Intermediate-mass Stars

Helium-burning stars, in particular Cepheids, are especially difficult to model, as the choice of free parameters can greatly impact the shape of the blue loops—the part of the evolutionary track at which the instability strip is crossed. Contemporary one-dimensional stellar evolution codes, like Modules for Experiments in Stellar Astrophysics (MESA), come with a large number of free parameters that allow us to model the physical processes in stellar interiors under many assumptions. The uncertainties that arise from this freedom are rarely discussed in the literature despite their impact on the evolution of the model. We calculate a grid of evolutionary models with MESA, varying several controls, like solar mixture of heavy elements, mixing-length theory prescription, nuclear reaction rates, the scheme to determine convective boundaries, atmosphere model, and temporal and spatial resolution, and quantify their impact on age and location of the evolutionary track on the H-R diagram from the main sequence until the end of core helium burning. Our investigation was conducted for a full range of masses and metallicities expected for classical Cepheids. The uncertainties are significant, especially during core helium burning, reaching or exceeding the observational uncertainties of logTeff and logL for detached eclipsing binary systems. For ≥9 M ⊙ models, thin convective shells develop and evolve erratically, not allowing the models to converge. A careful inspection of Kippenhahn diagrams and convergence study is advised for a given mass and metallicity, to assess how severe this problem is and to what extent it may affect the evolution.

Cosmic rays, radiocarbon and the beginning of high-energy particle physics: Marietta Blau and the “disintegration stars”

Abstract This brief review describes the discovery of cosmic rays by Victor Hess from the Vienna Radium Institute and the later contribution of Marietta Blau through her observation of “disintegration stars” in photographic emulsion plates exposed to cosmic-ray bombardment. Marietta Blau, a nearly forgotten cosmic-ray pioneer from the Vienna Radium Institute, developed the nuclear emulsion technique for studying nuclear reactions, eventually discovering the disintegration of nuclei through high-energy cosmic rays. Blau survived the Holocaust by escaping to Mexico City from 1939 to 1944. Starting in 1948 at Columbia University, later as a staff member of Brookhaven National Laboratory and then University of Miami, she performed fundamental and original research with nuclear emulsions exposed to 3-GeV protons at the Brookhaven Cosmotron and to 6-GeV protons at the Berkeley Bevatron. Blau returned to Vienna in 1960, where at the Radium Institute a classical β-decay counting facility for radiocarbon dating had been installed, which was finally superseded by the Vienna Environmental Research Accelerator (VERA), a modern versatile accelerator mass spectrometry facility.

Systematic study of theoretical estimation of nuclear reaction cross section of proton-induced reactions on Neodymium target upto 65 MeV using TALYS-1.96 code

Abstract Systematic study of theoretical estimation of nuclear cross section of charged particle induced reactions on rare earth nuclei has been carried out. The production cross section of the $^{150,149,148,146,144,143,141}$Pm and $^{149,147}$Nd nuclei were calculated theoretically via proton induced reaction on neodymium using TALYS (version 1.96) code in the default mode, with different combination of nuclear models as well as using adjusted nuclear model parameters from reaction threshold to the proton energy upto 65 MeV. The theoretically computed results were compared with the experimental results taken from EXFOR database and literature, reported by various research groups. Moreover, the effect of the various Level Density Models (LDMs), Preequilibrium Models (PEs), Optical Model Potentials (OMPs), gamma Strength Functions ($\gamma$SFs) in the cross section calculation were taken into consideration. The present theoretical analysis will help to understand the theory of nuclear reaction models and improve the evaluated nuclear data libraries.

Highly sensitive site-specific SUMOylation proteomics in Arabidopsis.

SUMOylation-the attachment of a small ubiquitin-like modifier (SUMO) to target proteins-plays roles in controlling plant growth, nutrient signalling and stress responses. SUMOylation studies in plants are scarce because identifying SUMOylated proteins and their sites is challenging. To date, only around 80 SUMOylation sites have been identified. Here we introduce lysine-null SUMO1 into the Arabidopsis sumo1 sumo2 mutant and establish a two-step lysine-null SUMO enrichment method. We identified a site-specific SUMOylome comprising over 2,200 SUMOylation sites from 1,300 putative acceptors that function in numerous nuclear processes. SUMOylation marks occur on several motifs, differing from the canonical ψKxE motif in distant eukaryotes. Quantitative comparisons demonstrate that SUMOylation predominantly enhances the stability of SUMO1 acceptors. Our study delivers a highly sensitive and efficient method for site-specific SUMOylome studies and provides a comprehensive catalogue of Arabidopsis SUMOylation, serving as a valuable resource with which to further explore how SUMOylation regulates protein function.

Candidate-nuclei for observation of a bound dineutron. Part II: The (n,2n + n) and (γ,2n) nuclear reactions

This is a second part of a survey for stable isotopes in the mass range 90 < A < 210, to find candidates showing the bound dineutron nuclear reaction output channel after irradiation with neutrons or photons. To this end, the neutron capture reaction cross sections were calculated in the (0 - 30) MeV energy range with the TALYS-2.0 code for nuclei in the outgoing channel, which are expected to host bound dineutrons. This study was performed to find appropriate candidates to observe bound dineutron decay meeting the criteria based on the (n, γ) resonance cross section analysis. This study opens up a new direction in dineutron research with the (n, n2+n) and (γ, n2) nuclear reactions.

Exploring constituent redistribution in irradiated U-19Pu-14Zr fuel via electron probe microanalysis

The phenomena of constituent redistribution, wherein a previously homogeneous metallic fuel forms discrete, radially concentric compositional zones upon irradiation was investigated by examining an irradiated U-19Pu-14Zr fuel (where numbers represent wt. %) with a burnup of 11.5 at.% with electron probe microanalysis (EPMA) and quadruple inductively coupled plasma mass spectroscopy (Q-ICP-MS).EPMA-generated U, Pu, and Zr compositional data obtained from a diameter traverse of the sample was converted to mass and was used to: 1) compare the overall fuel element analysis results between the two methods, 2) determine the number of compositionally distinct zones forming as a result of constituent redistribution; and 3) quantify the post-irradiation loss or gain of U, Pu, and Zr atoms in each distinct compositional zone.Weight percent concentrations of U, Pu, and Zr for the overall cross section compare favorably between the two analytical methods, suggesting that the spatially resolved EPMA analysis complements bulk chemical analysis.Among the four identified compositional zones, post-irradiation quantification of U, Pu, and Zr elemental atom content changes shows that the quantity of U atoms lost from the innermost zone is slightly less than the quantity of U atoms gained by the middle two zones, and the quantity of Zr atoms lost from the high-U third zone is slightly less than is gained by the two innermost zones. Pu is lost from all four zones, although the innermost zone and the high-U third zone lose a significantly higher percentage (> 22 %) of their initial Pu atoms than the other two zones. For all three elements, EPMA cannot distinguish between atoms lost due to transport to a different zone from atoms lost due to nuclear processes; however, the insight gained from using this process can be used to experiment with new modeling techniques to predict constituent redistribution in U-Pu-Zr fuels.

The Folding Potential of Elastically Scattered d+ 24Mg Employing B3Y-Fetal Interaction within the Double Folding Model Framework

Study’s Excerpt/Novelty In this study, double-folding model with the B3Y-Fetal interaction was applied to derive optical potentials for deuteron scattering from 24Mg. The research validates the efficacy of mass-dependent interactions in optical potential calculations by accurately reproducing experimental differential cross-sections across a broad energy range. This work advances the understanding of nuclear reactions by demonstrating the suitability of the B3Y-Fetal interaction in modeling elastic scattering phenomena. Full Abstract The analysis of the deuteron scattering from was performed in the elastic channel using the double-folding model to evaluate the optical potentials of the present study. Both the real and the imaginary parts of the optical potentials were computed using a mass-dependent interaction (B3Y-Fetal) in the double-folding formalism. The derived double-folding potentials were used to analyse the differential cross-sections of within the energy range of 60-170 MeV. With the derived optical potentials, the reaction and differential cross-sections of were extracted in the optical model. The plots of the computed differential cross-sections were made and the results were compared to those obtained experimentally to ascertain the suitability of the derived potentials and the B3Y-Fetal interaction. In conclusion, the optical potentials obtained using the double-folding model with the B3Y-Fetal interaction were successful in reproducing the experimental data.

Development of Critical Thinking in Chemistry Teaching

The critical thinking is an important part of education supported by the Czech curriculum documents, and its importance is now being discussed in the context of the development of artificial intelligence. In the teaching of (not only) chemistry, the critical thinking can be purposefully developed through appropriate activities. The article presents three comprehensive teaching tasks for chemistry education that have the potential to develop critical thinking: Genetically Modified Crops (a task using the problem-based learning and analysis of information sources), Nuclear Energy and Spent Nuclear Fuel Management (a task focused on critical reading of text, reasoning and working with artificial intelligence) and Reaction Kinetics (research-oriented laboratory work enhanced with elements of graph and data interpretation and reasoning). Building critical thinking skills in chemistry is essential for understanding abstract concepts and acquiring skills that enable students to approach chemistry topics responsibly and knowledgeably in everyday life. Full text English translation is available in the on-line version.

Electron Screening in Laboratory Nuclear Reactions

A thorough understanding of nuclear reaction rates at low energies is essential for improving our understanding of energy generation in stars and primordial and stellar nucleosynthesis. At low energies, fusion reactions between charged particles are strongly suppressed by the presence of the Coulomb barrier, which classically inhibits the penetration of one nucleus into another. The barrier penetration causes the cross section to have a steep energy dependence at low energies, making cross section measurements very challenging. Furthermore, little is known about the impact of surrounding electrons in stellar plasmas that are currently beyond the reach of experiments. As a result, measuring the bare cross sections as accurately as possible is essential. Reaction rate measurements at very low energies have been made possible in recent years by the development of high-current low-energy accelerators as well as enhanced target and detection methods. Nevertheless, the presence of atomic electrons, which alter the Coulomb barrier by screening the nuclear charge and increase the cross section at low energies compared to the case of bare nuclei, complicates these observations. A review of the experimental and corresponding theoretical work on laboratory electron screening performed so far will be presented.

Development of Target Holder for the First Experiment on an Alternative Route for 64Cu Radioisotope Production by Secondary Neutron Irradiation of a 64ZnO Target

The target holder, as part of the target system for cyclotron-based radioisotope production, plays a crucial role in successful radioisotope production. The target holder has to be designed and developed so that it will not deform or melt should a beam of energetic particles irradiate the target. In this work, we develop and test a target holder for 64Cu radioisotope production. The thermal distribution and structural analysis are simulated using ANSYS software. Based on the ANSYS simulation results, a maximum temperature of 84°C occurred on the titanium foil, while the maximum temperature in the target holder body was 35.6°C when an 11-MeV proton beam with a beam current of 25 μA was bombarded on the target holder. We successfully test the target holder, and for the first time, we experimentally produce a 64Cu radioisotope by secondary neutron irradiation of the 64ZnO target. Using 11-MeV protons with a proton beam current of 25 μA incident on a 1-mm Ti foil for 5 min, we were able to generate secondary neutrons, and then the secondary neutrons irradiated 1 g of the enriched 64ZnO target. Copper-64 produced from the 64Zn(n,p)64Cu nuclear reaction was eventually detected using a portable gamma spectrometer, and its radioactivity was measured using a dose calibrator. For the first time, this experimental study confirmed that as much as 48.8 ± 6.2 MBq/μAh radioactivity of 64Cu was produced with no observed radioactive impurities.

Formation and Evolution of Special Stellar Types: A Comprehensive Study of Special Stars.

This article presents a comprehensive study of the formation, evolution, and distinctive characteristics of special stellar types, including protostars, super-giants, pulsars, red giants, etc. By exploring the life cycles of these stars, we gain a deeper understanding of the nuclear reactions, gravitational influences, and electromagnetic spectra that govern their development and eventual demise. Through a synthesis of observational data, theoretical models, and recent advancements in astrophysics, this research aims to elucidate the intricate processes driving the life cycles of these stellar phenomena. The findings contribute to the broader knowledge of stellar dynamics, offering insights into the mechanisms of stellar evolution and the fundamental forces shaping our universe.

Polarization effects of hot nuclear matter on the fusion of heavy ions

Within the framework of the modified density-dependent Seyler–Blanchard approach in the [Formula: see text] approximation, the polarization effects of hot nuclear matter (PEHNM) are investigated on the fusion process of 16 different colliding systems in the mass range [Formula: see text]. In order to calculate the nucleus–nucleus potential, we use the double-folding (DF) model supplemented with the thermal effects of compound nucleus and also a repulsive potential that takes into account the incompressibility of the nuclear matter. The calculations of the fusion cross-sections are performed based on the couplings to the low-lying [Formula: see text] and [Formula: see text] vibrational states in both target and projectile. The sensitivity of sub-barrier fusion cross-sections to the polarization effects is evident from this study. The obtained results reveal that the modified form of the DF potential in the presence of the PEHNM appropriately reproduces the energy-dependent behavior of the experimental fusion cross-sections for the studied reactions. The role of the polarization effects on the fusion barriers as well as the inner part of the potential is also discussed.

Following the yellowcake road: exploring the colonial roots and routes of Australian radioactive minerals, 1900s–1950s

ABSTRACT Over the past 40 years, environmental justice activists and scholars have drawn greater attention to the disproportionate environmental burdens borne by marginalised communities. This includes the consequences of ‘nuclear colonialism’, a phenomenon defined as constituting ‘a system of domination through which governments and corporations target indigenous peoples and their lands to maintain the nuclear production process’. In this article, I seek to complicate this definition of nuclear colonialism by exploring the role of uranium mining in consolidating both British and Australian settler colonial power during the first half of the twentieth century. I will do so through an examination of Australian uranium’s roots and routes as both a manifestation and facilitator of settler colonialism in Australia between 1900 and 1955. Combining sources from both British and Australian archives, this article seeks to contribute to emergent scholarship on the colonial dimensions of mineral extraction in two ways. Firstly, by explicating the role uranium played in fuelling the extractive mentalities of settler colonial Australia. And secondly, by exploring uranium extraction’s contribution to the consolidation of the British Empire’s waning power in the mid-twentieth century.

Determination of electron screening potential of 6Li(p, [formula omitted])3He reaction using Multi Layer Perceptron based neural network

Understanding nuclear reactions between light-charged nuclei in the sub-Coulomb energy region is crucial for several astrophysical processes. Accurate determination of the reaction cross-section within the astrophysically important Gamow range is challenging due to electron screening. Various methods, including polynomial fits, R-Matrix, and the indirect Trojan Horse Method (THM), have estimated electron screening energies that exceed the adiabatic limit. This study aims to derive the bare astrophysical S-factor for the reaction 6Li(p,α)3He and to extract electron screening energies using Multi-Layer Perceptron-based Artificial Neural Network (ANN) analysis. Experimental S-factors for 6Li(p,α)3He, obtained from the literature, are reanalyzed with the ANN algorithm to determine the energy-dependent S-factor. The bare astrophysical S-factor is calculated from data above 60 keV, where electron screening is negligible. The electron screening potential is then derived by comparing the shielded S-factor with the bare S-factor. The ANN-based analysis yields an electron screening potential of 220 eV, suggesting that ANN could be a viable tool for estimating electron screening potentials in light nuclei reactions.

Assessment of aerosol radioactivity in the atmospheric air of populated areas

Introduction. Due to the tense situation in the world, which may lead to deliberate emergencies at radiation-hazardous facilities as a result of terrorist or sabotage actions, the availability of methods for operational control of radioactive aerosols in the atmospheric air, as well as knowledge of background levels of α- and β-activity of aerosols in the locations of nuclear power facilities, mining and processing facilities The aim of the study was to assess the radioactivity of aerosols in the atmospheric air according to the indices of α- and β-activity (using the example of the cities of Voronezh, Novovoronezh, Pavlovsk, Lipetsk, Stary Oskol). Materials and methods. Atmospheric air sampling was carried out using a flow meter-sampler of PU-5 aerosol mixtures. The α- and β-activity of the surface of the AFA-RSP-20 filters was measured with the MKS-AT1117M dosimeter-radiometer with interchangeable detection units BDPA-01 and BDPB-01. Results. The results of measurements of aerosols α- and β-activity in the atmospheric air in all control points in the territories of populated places established the α-activity of the aerosols to vary from 1.10 • 10–3 to 6.75 • 10–3 Bq/m3, total (total) β-activity – from 3. 49 • 10–3 to 2.12 • 10–2 Bq/m3. The maximum indices values took place at control points near the open-pit mining of the Shkurlatovsky granite deposit (near Pavlovsk, Voronezh region). Limitations. The limitations of the study are related to possible errors of the proposed and tested methodology, single (one-time) measurements, variable meteorological conditions affecting a specific result. Conclusion. The maximum values of aerosols α- and β-activity in the atmospheric air of populated areas are determined by the results of one-time measurements (6.75 • 10–3 Bq/m3 and 2.12 • 10–2 Bq/m3) do not cause concerns for the health of the living population.