Search Results (163)

Laboratory magnetoplasmas can become an intriguing experimental environment for fundamental studies relevant to nuclear astrophysics processes. Theoretical predictions indicate that the ionization state of isotopes within the plasma can significantly alter their lifetimes, potentially due to nuclear and atomic mechanisms such as bound-state β-decay. However, only limited experimental evidence on this phenomenon has been collected. PANDORA (Plasmas for Astrophysics, Nuclear Decay Observations, and Radiation for Archaeometry) is a novel facility which proposes to investigate nuclear decays in high-energy-density plasmas mimicking some properties of stellar nucleosynthesis sites (Big Bang Nucleosynthesis, s-process nucleosynthesis, role of CosmoChronometers, etc.). This paper focuses on the case of ⁷Be electron capture (EC) decay into ⁷Li, since its in-plasma decay rate has garnered considerable attention, particularly concerning the unresolved Cosmological Lithium Problem and solar neutrino physics. Numerical simulations were conducted to assess the feasibility of this possible lifetime measurement in the plasma of PANDORA. Both the ionization and atomic excitation of the ⁷Be isotopes in a He buffer Electron Cyclotron Resonance (ECR) plasma within PANDORA were explored via numerical modelling in a kind of “virtual experiment” providing the expected in-plasma EC decay rate. Since the decay of ⁷Be provides γ-rays at 477.6 keV from the ⁷Li excited state, Monte-Carlo GEANT4 simulations were performed to determine the γ-detection efficiency by the HPGe detectors array of the PANDORA setup. Finally, the sensitivity of the measurement was evaluated through a virtual experimental run, starting from the simulated plasma-dependent γ-rate maps. These results indicate that laboratory ECR plasmas in compact traps provide suitable environments for β-decay studies of ⁷Be, with the estimated duration of experimental runs required to reach 3σ significance level being few hours, which prospectively makes PANDORA a powerful tool to investigate the decay rate under different thermodynamic conditions and related charge state distributions. Full article

(1) Background: Ionizing radiation in the Earth’s atmosphere drives key chemical transformations affecting atmospheric composition. Despite their environmental relevance, experimental data on proton collisions with hydrofluorocarbons remain limited, and theoretical models for total cross-sections and stopping power are still underdeveloped. (2) Methods: This study applies Rudd’s semiempirical model to calculate proton impact ionization cross-sections for the CF₃CH₂F molecule, considering contributions from both outer and inner electron shells. The model enables the estimation of differential cross-sections and the average energy of secondary electrons. In addition, we calculate the photoionization cross-sections using a discretized representation of the continuum—the so-called pseudo-spectrum—obtained through TDDFT with PBE0 as an exchange–correlation functional and compare it with the cross-section obtained for proton impact in the high-energy limit. (3) Results: The Rudd model proves highly adaptable and suitable for numerical applications. However, its validation is hindered by the scarcity of experimental data. Existing models, such as SRIM and Bethe–Bloch, show significant discrepancies due to their limited applicability at intermediate energies and lack of molecular structure consideration. (4) Conclusions: A comparison between the Rudd and BEB models reveals strong agreement in the analyzed energy range. This consistency stems from both models accounting for the molecular structure of the target, as well as from the fact that protons and electrons possess charges of the same magnitude, supporting a coherent description of ionization processes at these energies. Full article

Ion interactions with molecular structures give insights into physicochemical processes in the cosmos, radiation damage, plasma, combustion, and biomass conversion reactions. At the atomic scale, these interactions lead to excitation, ionization, and dissociation of the molecular components of structures found across all these environments. Furan, cyclic aromatic ether (C₄H₄O), serves as a gas-phase deoxyribose analog and is crucial for understanding key pathways in renewable biomass conversion, as its derivatives are versatile molecules from lignocellulosic biomass degradation. Therefore, collisions of H₃⁺ and C⁺ ions with gas-phase furan molecules were investigated in the 50–1000 eV energy range, exploiting collision-induced emission spectroscopy. High-resolution fragmentation spectra measured at 1000 eV for both cations reveal similar structures, with C⁺ collisions resulting in more significant furan fragmentation. Relative cross-sections for product formation were measured for H₃⁺ + C₄H₄O collisions. Possible collisional processes and fragmentation pathways in furan are discussed. These results are compared with those for tetrahydrofuran and pyridine to illustrate how the type and charge of the projectile influence neutral fragmentation in heterocyclic molecules. Full article

Cellulose is a sustainable biopolymer, being renewable and abundant, non-toxic, biodegradable, and easily functionalizable. However, the development of hydrogels for tissue engineering applications presents significant challenges that require interdisciplinary expertise, given the intricate and dynamic nature of the human body. This paper delves into current research focused on creating advanced cellulose-based hydrogels with tailored mechanical, biological, chemical, and surface properties. These hydrogels show promise in healing, regenerating, and even replacing human tissues and organs. The synthesis of these hydrogels employs a range of innovative techniques, including supramolecular chemistry, click chemistry, enzyme-induced crosslinking, ultrasound, photo radiation, high-energy ionizing radiation, 3D printing, and other emerging methods. In the realm of tissue engineering, various types of hydrogels are explored, such as stimuli-responsive, hybrid, injectable, bio-printed, electrospun, self-assembling, self-healing, drug-releasing, biodegradable, and interpenetrating network hydrogels. Moreover, these materials can be further enhanced by incorporating cell growth factors, biological molecules, or by loading them with cells or drugs. Looking ahead, future research aims to engineer and tailor hydrogels to meet specific needs. This includes exploring safer and more sustainable materials and synthesis techniques, identifying less invasive application methods, and translating these studies into practical applications. Full article

This study employs simulation tools to design and evaluate lightweight, lead-free polymer composites incorporating polytetrafluoroethylene (PTFE), polyethylene (PE), and polyetherimide (PEI) for gamma radiation shielding in nuclear medicine. Targeting clinically relevant photon energies from Tc-99m (140 keV), I-131 (364 keV), and Cs-137 (662 keV), composites’ structural and shielding performance with Bi₂O₃ and WO₃ was assessed using XCOM and Phy-X/PSD. PEI emerged as the most suitable polymer for load-bearing and thermally exposed applications, offering superior mechanical stability and dimensional integrity. Bi₂O₃-WO₃ fillers for Tc-99m achieved a ~7000-fold increase in MAC, I-131 ~2063-fold, and Cs-137 ~1370-fold compared to PbO₂. The PEI-75Bi₂O₃-25WO₃ achieved a ~21-fold reduction in half-value layer (HVL) compared to lead for Tc-99m. For higher-energy isotopes of I-131 and Cs-137, HVL reductions of ~0.44-fold and ~0.08-fold, respectively, were achieved. The results demonstrate that high-Z dual filler polymer composites have an equal or enhanced attenuation properties to lead-based shielding, whilst also enhancing the polymer composites’ mechanical and thermal characteristics. As the use of ionizing radiation increases, so does the potential risks; high-Z dual filler polymer composites provide a sustainable, lightweight, non-toxic alternative to conventional lead shielding. Full article

Tantalum is extensively used in inertial confinement fusion research for targets in radiation transport experiments, hohlraums in magnetized fusion experiments, and lining foams for hohlraums to suppress wall motions. To comprehend the physical processes associated with these applications, detailed information regarding the ionization composition and electrical conductivity of tantalum plasma across a wide range of densities and temperatures is essential. In this study, we calculate the densities of ionization species and the electrical conductivity of partially ionized, nonideal tantalum plasma based on a simplified theoretical model that accounts for high ionization states up to the atomic number of the element and the lowering of ionization energies. A comparison of the ionization compositions between tantalum and copper plasmas highlights the significant role of ionization energies in determining species populations. Additionally, the average electron–neutral momentum transfer cross-section significantly influences the electrical conductivity calculations, and calibration with experimental measurements offers a method for estimating this atomic parameter. The impact of electrical conductivity in the intermediate-density range on the laser absorption coefficient is discussed using the Drude model. Full article

Star-forming galaxies are hosts of dominant populations of recently formed, hot, massive stars, which give rise to conspicuous stellar spectral features and provide the ionizing fluxes. Strong outflows of these stars shape their properties. These winds affect the evolution and the output of ionizing radiation, as well as the energy and momentum input in the interstellar medium and the chemical enrichment. Many properties of massive stars become even more extreme at a low metallicity. Owing to the pioneering observations of young, metal-poor stellar populations, both locally with HST and large ground-based facilities and at high redshift with JWST, we are at a key moment to assess our understanding of hot massive stars in these galaxies. Stellar population synthesis is a key tool. I will demonstrate how population models of hot, massive stars help to address some issues at the forefront of current research. The recent advent of new evolutionary and atmosphere models of massive stars probing new parameter space allows us to characterize the properties of nearby and distant populations. Full article

A comparative study on the synergistic effect of the total ionizing dose and neutron single event effect on a SiC MOSFET and Si MOSFET was performed based on the ⁶⁰Co γ source and the high-pressure multiplier 14 MeV neutron source at the China Institute of Atomic Energy. First, a γ-ray total ionizing dose experiment was performed on these two devices, and the differences in the total ionizing dose damage of the SiC and Si MOSFETs were analyzed. Then, neutron single event effect experiments were performed to investigate the effects of different doses on the single event effect for the devices. The results indicate that the unhardened SiC MOSFET has stronger resistance to the total ionizing dose compared with hardened Si MOSFET. During the 14 MeV neutron irradiation experiment, no single event burnout was observed in either device, but single event transients were observed. Even though the hardened Si MOSFETs are capable of suppressing single event transient currents at a higher drain bias, the trapped charge concentration of SiC MOSFETs due to irradiation is smaller than that of Si MOSFETs, which improves their resistance to the total ionizing dose and makes them less affected by the synergistic effect of the total ionizing dose and neutron single event effects. The research results can provide some guidelines for the radiation hardening technology of power devices used in aerospace and nuclear industries. Full article

Semiconductors characterized by ultrawide bandgaps (UWBGs), exceeding the SiC bandgap of 3.2 eV and the GaN bandgap of 3.4 eV, are currently under focus for applications in high-power and radio-frequency (RF) electronics, as well as in deep-ultraviolet optoelectronics and extreme environmental conditions. These semiconductors offer numerous advantages, such as a high breakdown field, exceptional thermal stability, and minimized power losses. This study used numerical simulation to investigate, at the material level, the single-particle radiation response of various UWBG semiconductors, such as aluminum gallium nitride alloys (Al_xGa_1−xN), diamond, and β-phase gallium oxide (β-Ga₂O₃), when exposed to ground-level neutrons. Through comprehensive Geant4 simulations covering the entire spectrum of atmospheric neutrons at sea level, this study provides an accurate comparison of the neutron radiation responses of these UWBG semiconductors focusing on the interaction processes, the number and nature of secondary ionizing products, their energy distributions, and the production of electron–hole pairs at the origin of single-event effects (SEEs) in microelectronics devices. Full article

Radiation impacts on space-based systems operating on various orbits are evaluated in this paper. Specifically, satellite operations in Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geosynchronous Orbit (GEO) are analyzed. Special focus is given on quantifying the effect of high-energy particle space radiation on materials used for critical power components, where component fault can lead to total mission failure. Methods, using multiple computational platforms for the quantification of non-ionizing energy loss (NIEL) and displacement damage dose (DDD), are used to assess semiconductor damage at specific orbital altitudes. Detailed simulations were conducted for Gallium Arsenide Indium Phosphide (GaInP/GaAs/Ge) solar cells with various cover glass thicknesses, and the survivability of GaInP/GaAs/Ge cells was compared with that of Si cells. It was assessed that radiation exposure due to high-energy protons at 10,000 km is more prevalent than 20,000 km orbits and that electron bombardment is a major electronic damage culprit. For MEO at 10,000 km, MEO at 20,000 km, and GEO at 36,000 km, we determined the 1-year maximum power (Pmax) losses due to protons to be 23%, 8%, and 1% and losses due to electrons to be 11%, 14%, and 10%. Total integrated spectra Pmax losses for those altitudes are 25%, 16%, and 10%, respectively. Full article

Preoperative or postoperative radiation therapy is broadly employed in patients with rectal carcinoma. Radiotherapy directs high-energy beams of ionizing radiation toward the tumor area to destroy cancer cells. High radiation doses are needed for cell killing. The radiation exposure of the healthy tissues/organs may lead to carcinogenesis. This study describes the evolving role of radiotherapy in rectal cancer management. The present report also reviews epidemiological and dosimetric studies related to the radiation-induced second malignancies from pelvic radiotherapy. Some epidemiological studies have concluded that the second-cancer risk in patients subjected to radiation therapy does not increase compared to unexposed rectal cancer patients. Other researchers found an elevated or a marginally increased probability for second-cancer induction. Dosimetric studies reported cancer risk estimates for critical organs or tissues in the near and far periphery of the treatment volume. Useful information about the effect of the treatment parameters such as the irradiation technique, photon beam energy, and fractionation schedule on the organ-specific second-cancer risk was derived from the dose data analysis. The knowledge of these effects is needed for the selection of the optimal treatment parameters enabling a reduction in the resultant risk of carcinogenesis. Full article

Breast cancer is a global health issue that, when in the metastasis stage, is characterized by the lack of estrogen receptor-α, the progesterone receptor, and human epidermal growth receptor expressions. The present study analyzed the differential gene expression related to the immune system affected by ionizing radiation and estrogen in cell lines derived from an experimental breast cancer model that was previously developed; where the immortalized human breast epithelial cell line MCF-10F, a triple-negative breast cancer cell line, was exposed to low doses of high linear energy transfer α particle radiation (150 keV/μm), it subsequently grew in the presence or absence of 17β-estradiol. Results indicated that interferon-related developmental regulator 1 gene expression was affected in the estrogen-treated cell line; this interferon, as well as the Interferon-Induced Transmembrane protein 2, and the TNF alpha-induced Protein 6 gene expression levels were higher than the control in the Alpha3 cell line. Furthermore, the interferon-related developmental regulator 1, the Interferon-Induced Transmembrane protein 2, the TNF alpha-induced Protein 6, the Nuclear Factor Interleukin 3-regulated, and the Interferon-Gamma Receptor 1 showed high expression levels in the Alpha5 cell line, and the Interferon Regulatory Factor 6 was high in the Tumor2 cell line. Additionally, to further strengthen these data, publicly available datasets were analyzed. This analysis was conducted to assess the correlation between estrogen receptor alpha expression and the genes mentioned above in breast cancer patients, the differential gene expression between tumor and normal tissues, the immune infiltration level, the ER status, and the survival outcome adjusted by the clinical stage factor. It can be concluded that the genes of the interferon family and Tumor Necrosis factors can be potential therapeutic targets for breast cancer, since they are active before tumor formation as a defense of the body under radiation or estrogen effects. Full article

Due to the high environmental burden of plastics, this study aimed to evaluate the environmental performance of chemical recycling of plastic waste through Life Cycle Assessment (LCA), focusing on pyrolysis oil production as the primary output. A pyrolysis plant in Almería, Spain, was chosen as a case study. The results indicate that the production of 1 L of pyrolysis oil from plastic waste generates about 0.032 kg CO₂ eq and a water consumption of 0.031 m³, with other impact categories registering values of less than 0.1 kg/L or 0.01 m²a crop eq/L, reducing impacts in 17 out of 18 categories compared to fossil diesel. In addition, its chemical and physical properties, close to those of fossil diesel, suggest its suitability for internal combustion engines, although as a blend rather than a complete substitute. Chemical recycling also appears to be more environmentally favorable than incineration and landfilling in all 18 impact categories, achieving significant benefits, including a reduction in global warming of −3849 kg CO₂ eq/ton, ionizing radiation of −22.4 kBq Co-60 eq/ton, and fossil resource consumption of −1807.5 kg oil eq/ton. These results, thus, highlight the potential dual role of chemical recycling of plastic waste, both in mitigating environmental impacts and in supporting circular economy goals by reducing demand for virgin plastics. However, although it appears to be a promising technology, challenges associated with high energy requirements, raw material variability, and scale infrastructure still need to be addressed to ensure industrial competitiveness and significant environmental benefits. Full article

This study conducts a comparative analysis of cystamine (RSSR), a disulfide, and cysteamine (RSH), its thiol monomer, to evaluate their efficacy as radioprotectors and antioxidants under high linear energy transfer (LET) and high-dose-rate irradiation conditions. It examines their interactions with reactive primary species produced during the radiolysis of the aqueous ferrous sulfate (Fricke) dosimeter, offering insights into the mechanisms of radioprotection and highlighting their potential to enhance the therapeutic index of radiation therapy, particularly in advanced techniques like FLASH radiotherapy. Using Monte Carlo multi-track chemical modeling to simulate the radiolytic oxidation of ferrous to ferric ions in Fricke-cystamine and Fricke-cysteamine solutions, this study assesses the radioprotective and antioxidant properties of these compounds across a variety of irradiation conditions. Concentrations were varied in both aerated (oxygen-rich) and deaerated (hypoxic) environments, simulating conditions akin to healthy tissue and tumors. Both cystamine and cysteamine demonstrate radioprotective and strong antioxidant properties. However, their effectiveness varies significantly depending on the concentration employed, the conditions of irradiation, and whether or not environmental oxygen is present. Specifically, excluding potential in vivo toxicity, cysteamine substantially reduces the adverse effects of ionizing radiation under aerated, low-LET conditions at concentrations above ~1 mM. However, its efficacy is minimal in hypoxic environments, irrespective of the concentration used. Conversely, cystamine consistently offers robust protective effects in both oxygen-rich and oxygen-poor conditions. The distinct protective capacities of cysteamine and cystamine underscore cysteamine’s enhanced potential in radiotherapeutic settings aimed at safeguarding healthy tissues from radiation-induced damage while effectively targeting tumor tissues. This differential effectiveness emphasizes the need for personalized radioprotective strategies, tailored to the specific environmental conditions of the tissue involved. Implementing such approaches is crucial for optimizing therapeutic outcomes and minimizing collateral damage in cancer treatment. Full article

This manuscript focuses on studying the radiation response of the Commercial-off-the-shelf (COTS) AD524CDZ operational amplifier. Total Ionizing Dose (TID) effects were tested using low-dose ⁶⁰Co irradiation. Single-Event Effect (SEE) sensitivity was studied on this operational amplifier using a 105 MeV proton beam. Additionally, further study of the SEE response was carried out using a Two-photon absorption laser to scan some sensitive sectors of the die. For this laser experiment, different gain setups and laser energies were employed to determine how the Single Event Transient (SET) response of the device was affected based on the test configuration. The results from the TID experiments revealed that the studied device remained functional after 100 krads (Si). Proton experiments revealed the studied device exhibited a high SET response with a maximum DC offset SET of about 1.5 V. Laser experiments demonstrated that there was a clear SET reduction when using 10× and 1000× gain setups. Full article