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We present the latest precision measurements of the fluxes of all charged cosmic elementary particles, protons, electrons, antiprotons and positrons based on the first 10 years of data collected by the Alpha Magnetic Spectrometer on the International Space Station. These unique results, obtained with the same detector and with unprecedented precision in the uncharted energy range, provide precise experimental information and reveal new properties of cosmic charged elementary particles. In the absolute rigidity range of 60 to 525 GV, the antiproton-to-proton flux ratio is constant and the antiproton flux and proton flux have identical rigidity dependence. This behavior indicates an excess of high-energy antiprotons compared with traditional predictions of secondary antiprotons produced from the collision of cosmic rays. More importantly, from 60 to 525 GV, the antiproton flux and positron flux also show identical rigidity dependence. The positron-to-antiproton flux ratio is independent of energy, with its value of 2 established with percent-level accuracy. This unexpected observation suggests a common origin of high-energy antiprotons and positrons in the cosmos. [ABSTRACT FROM AUTHOR]

A measurement of the cosmic ray anisotropy on the arrival directions of elementary particles (electrons, positrons and protons) has been performed in galactic coordinates by the Alpha Magnetic Spectrometer onboard the International Space Station. The analysis is based on the sample of events collected in the first 10 years of data taking. The results are consistent with isotropy for all cosmic ray species and upper limits on the dipole amplitude have been computed. In particular, 95 % credible interval upper limits of δ < 1.50 % and δ < 0.34 % are obtained for positrons and electrons, respectively, above 16 GeV. On the other hand, the upper limit to the dipole anisotropy of protons above 200 GV is found to be δ < 0.30 %. [ABSTRACT FROM AUTHOR]

Introduction: A neural network was trained to accurately predict the entire singleevent specific energy spectra for use in alpha-particle microdosimetry calculations. Methods: The network consisted of 4 inputs and 21 outputs and was trained on data calculated using Monte Carlo simulation where input parameters originated both from previously published data as well as randomly generated parameters that fell within a target range. The 4 inputs consisted of the source-target configuration (consisting of both cells in suspension and in tissue-like geometries), alpha particle energy (3.97-8.78 MeV), nuclei radius (2-10 mm), and cell radius (2.5-20 mm). The 21 output values consisted of the maximum specific energy (zmax), and 20 values of the single-event spectra, which were expressed as fractional values of zmax. The neural network consisted of two hidden layers with 10 and 26 nodes, respectively, with the loss function characterized as the mean square error (MSE) between the actual and predicted values for zmax and the spectral outputs. Results: For the final network, the root mean square error (RMSE) values of zmax for training, validation and testing were 1.57 x10-2, 1.51 x 10-2 and 1.35 x 10-2, respectively. Similarly, the RMSE values of the spectral outputs were 0.201, 0.175 and 0.199, respectively. The correlation coefficient, R2, was > 0.98 between actual and predicted values from the neural network. Discussion: In summary, the network was able to accurately reproduce alphaparticle single-event spectra for a wide range of source-target geometries. [ABSTRACT FROM AUTHOR]

The structural, mechanical and radiation shielding properties of (69-x)B 2 O 3 -20TeO 2 -10Al 2 O 3 -1HfO 2 -xPr 6 O 11 (where x = 0, 0.25, 0.5, 0.75, 1 mol %) glass system were investigated. This study introduces a novel approach by incorporating Pr 6 O 11 into glass composition, highlighting its unique contributions to enhancing elastic properties, fracture toughness, hardness, and radiation shielding abilities. Experimental measurements were conducted within the energy range of 59.54–661.62 keV and theoretical calculations are made for MAC values. The presence of Pr 6 O 11 was noted to positively influence the gamma shielding capabilities. At 59.54 keV, the addition of 0.25 mol% Pr 6 O 11 increased the mass attenuation coefficient of the glass by 2.9 %, and the addition of 1 mol% Pr 6 O 11 increased it by 29.8 %. The addition of 0.25 mol% Pr 6 O 11 increased the fast neutron removal cross section of the glass by 4.4 %. Also, it is observed that the glass with 1 mol% Pr 6 O 11 is the best shielding material against alpha and proton particles. A significant enhancement of 24.36 % in the fracture toughness value was observed, increasing from 1.059 to 1.317 MPa m1/2 at 1 mol% Pr 6 O 11. Experimental hardness values increased from 3.374 to 3.985 GPa, resulting in an improvement of 18.11 % at 1 mol% Pr 6 O 11. The thermal stability (ΔT, °C) value demonstrated a notable increase from 85 to 106, indicating a significant 24.7 % improvement at 0.25 mol% Pr 6 O 11. [ABSTRACT FROM AUTHOR]

Improving the energy efficiency in generating high-energy proton or boron ions is crucial for advancing the feasibility of neutronless laser-based proton-boron (p-B11) fusion reactions. The primary objective of this work is to optimize the fusion energy efficiency of a proposed advanced p-B11 fusion scheme. In the proposed scheme, an ultrashort laser pulse is guided by a plasma channel filled with carbon-hydrogen (CH2) clusters. The MeV protons are generated by the Coulomb explosion (CE) of the cluster, which, therefore, interact with surrounding boron to produce alpha particles. To evaluate the fusion energy efficiency under various conditions, 2D particle-in-cell (PIC) simulations are used, supplemented with analytical calculations and estimations. The Bayesian optimization (BO) algorithm is utilized to optimize the key interaction parameters. The BO approach allows us to identify optimal cluster and laser parameters that would have higher fusion energy efficiency. [ABSTRACT FROM AUTHOR]

Radiated tumor cell‐derived extracellular vesicles (RT‐EVs) encapsulate abundant DNA fragments from irradiated tumor cells, in addition to acting as integrators of multiple tumor antigens. Accumulating evidence indicates these DNA fragments from damaged cells are involved in downstream immune responses, but most of them are degraded in cells before incorporation into derived RT‐EVs, thus the low abundance of DNA fragments limits immune responses of RT‐EVs. Here, this study found that different radiations affected fates of DNA fragments in RT‐EVs. Boron neutron capture therapy (BNCT) induced DNA accumulation in RT‐EVs (BEVs) by causing more DNA breaks and DNA oxidation resisting nuclease degradation. This is attributed to the high‐linear energy transfer (LET) properties of alpha particles from the neutron capture reaction of 10B. When being internalized by dendritic cells (DCs), BEVs activated the DNA sensing pathway, resulting in functional enhancements including antigen presentation, migration capacity, and cytokine secretion. After vaccination of the BEVs‐educated DCs (BEV@BMDCs), the effector T cells significantly expanded and infiltrated into tumors, suggesting robust anti‐tumor immune activation. BEV@BMDCs not only effectively inhibited the primary tumor growth and metastasis formation but also elicited long‐term immune memory. In conclusion, a successful DC vaccine is provided as a promising candidate for tumor vaccine. [ABSTRACT FROM AUTHOR]

The 4 He monopole form factor is studied by computing the transition matrix element of the electromagnetic charge operator between the 4 He ground-state and the p + 3 H and n + 3 He scattering states. The nuclear wave functions are calculated using the hyperspherical harmonic method, by starting from Hamiltonians including two- and three-body forces derived in chiral effective field theory. The electromagnetic charge operator retains, beyond the leading order (impulse approximation) term, also higher order contributions, as relativistic corrections and meson-exchange currents. The results for the monopole form factor are in fair agreement with recent MAMI data. Comparison with other theoretical calculations are also provided. [ABSTRACT FROM AUTHOR]

This article analyses the effects of deformation on the structure of CMnSi steel at various deformation levels. After hot forging, the structure of CMnSi steel comprises coarse-sized alpha and pearlite particles. The average grain size of steel after forging was 100 μm. After hot rolling, the grain size gradually decreases, with the average size of the ferrite and pearlite grains measured as 60 μm. After that, CMnSi steel was subjected to cold deformation at levels of 40%, 60%, and 80%. The grain size of the CMnSi steel sample after 80% cold deformation reached level 7, corresponding to about 25 μm. For a deformation level of 40%, the grain size was level 5, corresponding to 40 μm, while a deformation level of 60% produced a grain size of 35 μm, corresponding to level 6. In addition, scanning electron microscopy showed that after 80% deformation, smaller particles with a size of about 5 μm appear inside the parent particles. Moreover, energy-dispersive X-ray spectroscopy analysis revealed the carbide appearance in the form M23C6, with M being a mixture of Fe and Mn. These carbides have a fine size of about 1–2 μm and contribute to the prevention of particle growth during subsequent heat treatments. [ABSTRACT FROM AUTHOR]

Boron-enhanced proton therapy has recently appeared as a promising approach to increase the efficiency of proton therapy on tumor cells, and this modality can further be improved by the use of boron nanoparticles (B NPs) as local sensitizers to achieve enhanced and targeted therapeutic outcomes. However, the mechanisms of tumor cell elimination under boron-enhanced proton therapy still require clarification. Here, we explore possible molecular mechanisms responsible for the enhancement of therapeutic outcomes under boron NP-enhanced proton therapy. Spherical B NPs with a mode size of 25 nm were prepared by methods of pulsed laser ablation in water, followed by their coating by polyethylene glycol to improve their colloidal stability in buffers. Then, we assessed the efficiency of B NPs as sensitizers of cancer cell killing under irradiation with a 160.5 MeV proton beam. Our experiments showed that the combined effect of B NPs and proton irradiation induces an increased level of superoxide anion radical generation, which leads to the depolarization of mitochondria, a drop in their membrane mitochondrial potential, and the development of apoptosis. A comprehensive gene expression analysis (via RT-PCR) confirmed increased overexpression of 52 genes (out of 87 studied) involved in the cell redox status and oxidative stress, compared to 12 genes in the cells irradiated without B NPs. Other possible mechanisms responsible for the B NPs-induced radiosensitizing effect, including one related to the generation of alpha particles, are discussed. The obtained results give a better insight into the processes involved in the boron-induced enhancement of proton therapy and enable one to optimize parameters of proton therapy in order to maximize therapeutic outcomes. [ABSTRACT FROM AUTHOR]

High-performance radiation detectors are essential in many sectors spanning medical diagnostics, nuclear control, and particle physics. Ultrawide bandgap semiconductor materials have become one of the most promising candidates due to their excellent performance. Here, based on β-Ga2O3, a Schottky diode-type alpha particle detector was demonstrated. In order to reduce the reverse leakage current of the large-area device, the metal-oxide electrode PtOx was introduced to form high-barrier contacts (1.83 eV) with Ga2O3. The device exhibits a low leakage current density of 63 pA/cm2 at −100 V and apparent energy spectra of 241Am generated alpha particles with an energy of 5.486 MeV at various reverse voltages from −40 to −120 V. The charge collection efficiency (CCE) and energy resolution of the device (at −120 V) are 31.7% and 15.3%, respectively. Meanwhile, the mechanism of interaction between alpha particles and β-Ga2O3 was analyzed, and a 45° oblique incidence was adopted to increase the deposited energy of alpha particles in the depletion region. Furthermore, the differences between actual CCE and theoretical CCE are investigated as guidance for further improving detector performance. This work reveals the great potential and good prospects of Ga2O3 as an economical, efficient, and radiation-resistant ionizing radiation detector. [ABSTRACT FROM AUTHOR]

In the study, the influence of doping apatite-wollastonite (AW) glass-ceramics (GCs) with B 2 O 3 on the structural, physical, microstructural, and light and heavy particle interaction properties is presented. Using the solid-state reaction and the cold isostatic press method, pristine AW, 10 wt% (AW-B10), and 20 wt% (AW-B20) B 2 O 3 -doped AW GCs were prepared. The prepared GCs were subject to structural, chemical compositional, and surface morphological investigation through standard experimental processes. Furthermore, the neutron (fast and thermal) and charged radiation (electron, proton, alpha, and carbon ion) interactional parameters of the GCs were obtained through standard theoretical models and software. The density of AW (2.91 gcm−3) increases to about 2.957 and 2.986 gcm−3 as B 2 O 3 increases to 10 and 20 wt%, respectively. The presence of boron oxide supported the wollastonite phase to remain glass and suppressed crystallisation in the AW GCs. Doping AW with B 2 O 3 improved the interaction probabilities of the GCs with fast and thermal neutrons, electrons, protons, alpha particles, and carbon ions. B-rich AW is thus potentially useful as a target material in human tissues for boron neutron capture therapy for the management of cancer and tumours, isolating or shielding specific tissues in ion beam therapy processes, and other techniques that require the exposure of human tissues to irradiation. [ABSTRACT FROM AUTHOR]

α particles must be monitored to be managed as radioactive diagnostic agents or nuclear activity indicators. The new generation of perovskite detectors suffer from limited energy resolution, which affects spectroscopy and imaging applications. Here, we report that the solution-grown CsPbBr3 crystal exhibits a low and stable dark current (34.6 nA·cm−2 at 200 V) by thinning the as-grown crystal to decrease the high concentration CsPb2Br5 phase near the surface. The introduction of the Schottky electrode for the CsPbBr3 detector further reduces the dark current and improves the high-temperature stability. An energy resolution of 6.9% is achieved with the commercial electronic system, while the effects of air scattering and absorption are investigated. Moreover, 1.1% energy resolution is recognized by a full-customized readout application-specific integrated circuit without any additional signal processing, which matches well with the given parameters of the CsPbBr3 detector by reducing the parasitic capacitance and electronic noise. By developing a synergistic strategy of thinning the perovskite crystal, employing Schottky electrode and full-customised readout application specific integrated circuit to supress dark current and electronic noise, the authors report an energy resolution of 1.1% for perovskite α-particle detector. [ABSTRACT FROM AUTHOR]

Alpha-particle radionuclide-antibody conjugates are being clinically evaluated against solid tumors even when they moderately express the targeted markers. At this limit of lower tumor-absorbed doses, to maintain efficacy, the few(er) intratumorally delivered alpha-particles need to traverse/hit as many different cancer cells as possible. We complement antibody-radioconjugate therapies with a separate nanocarrier delivering a fraction of the same total injected radioactivity to tumor regions geographically different than those affected by targeting antibodies; these carrier-cocktails collectively distribute the alpha-particle emitters better. Methods: The efficacy of actinium-225 delivered by our carrier-cocktails was assessed in vitro and on mice with orthotopic MDA-MB-436 and/or MDA-MB-231 triple-negative breast cancers and/or an ectopic BxPC3 pancreatic cancer. Cells/tumors were chosen to express low-to-moderate levels of HER1, as model antibody-targeted marker. Results: Independent of cell line, antibody-radioconjugates were most lethal on cell monolayers. On spheroids, with radii greater than alpha-particles' range, carrier-cocktails improved killing efficacy (p < 0.0500). Treatment with carrier-cocktails decreased the MDA-MB-436 and MDA-MB-231 orthotopic tumor volumes by 73.7% and 72.1%, respectively, relative to treatment with antibody-radioconjugates alone, at same total injected radioactivity; these carrier-cocktails completely eliminated formation of spontaneous metastases vs. 50% and 25% elimination in mice treated with antibody-radioconjugates alone. In BxPC3 tumor-bearing mice, carrier-cocktails increased the median survival to 25–26 days (in male–female animals) vs. 20–21 days of mice treated with antibody-radioconjugates alone (vs. 17 days for non-treated animals). Survival with carrier-cocktail radiotherapy was further prolonged by pre-injecting low-dose, standard-of-care, gemcitabine (p = 0.0390). Conclusion: Tumor-agnostic carrier-cocktails significantly enhance the therapeutic efficacy of existing alpha-particle radionuclide-antibody treatments. [ABSTRACT FROM AUTHOR]

The objectives of the current study are to carry out soil gas radon (Rn) measurements, to evaluate the total inhalation effective dose, to determine risk levels over the lithological formations of the study area. The behavior investigation of Rn activity concentration distributions in dwellings and soils, and soil Rn mapping were also conducted. Soil gas Rn measurements were made at 102 sampling points by Markus 10 instrument. This data was combined with previously reported results from 140 indoor Rn RADTRAK dosimeters to determine the total inhalation effective dose and to conduct a statistical analysis. Overall, the Rn activity concentrations in soil and dwellings range from 4 to 66 kBq m−3 and from 15 to 140 Bq m−3, with averages of 31 ± 15 kBq m−3 and 41 ± 24 Bq m−3 respectively. The corresponding total inhalation effective dose ranges from 0.35 to 3.53 mSv y−1, with a mean value of 1.37 ± 0.58 mSv y−1. For soil gas Rn, the chlorite schist lithology showed the highest average concentration level. Which could be justified by the possible presence, within chlorite minerals, highly emitting zones of alpha particles, leading to the formation of radioactive halos. Normal and high‐risk level of Rn were found for about 82% and 11% of the total area surveyed respectively. These findings highlight the need for preventive measure against Rn exposure in homes within the investigated areas. This study contributes valuable insights into Rn distribution patterns and risk assessment, offering a basis for targeted interventions in the region. Plain Language Summary: Radon (222Rn (Rn or radon)) is the ubiquitous natural radioactive gas in the earth's crust. It is responsible for about 50% of the total dose received by the public from exposure to natural ionizing radiation. This gas have been recognized as the second leading cause of lung cancer in the world. The current work objectives are to measure the soil gas Rn activity concentrations, to assess the total inhalation dose received by the public and to determine risk levels of various lithological formations. In general, we found that the chlorite schist lithology had the highest average concentration level, due to the presence of minerals such as biotite and chlorite. Public exposure to Rn is greater indoors than outdoors with average inhalation dose relatively higher than the worldwide average. This is due to the numerous factors such as type of construction, building materials, low indoor air renewal rates, etc. The whole study area surveyed were classified as normal‐risk zones. These results reveal that preventive and protective measures against the public exposure to Rn are required from the construction of dwellings. Based on the activity concentrations distribution model and risk assessment, areas that could be targeted for potential intervention could be identified. Key Points: First in situ direct measurement of soil gas Rn activity concentration using Markus‐10 instrument in the various lithological formationsValuable insights into indoor and soil gas Rn distribution patterns and risk assessment, offering a basis for targeted interventionsProduction of a map of Rn distribution in the soil in this part of the country for the first time [ABSTRACT FROM AUTHOR]

We seek to understand the composition and variability of fast solar wind (FSW) and slow Alfvénic solar wind emerging from coronal holes (CHs). We leverage an opportune conjunction between Solar Orbiter and Parker Solar Probe (PSP) during PSP Encounter 11 to include compositional diagnostics from the Solar Orbiter Heavy Ion Sensor as these variations provide crucial insights into the origin and nature of the solar wind. We use potential field source surface and magnetohydrodynamic models to connect the observed plasma at PSP and Solar Orbiter to its origin footpoint in the photosphere and compare these results with the in situ measurements. A very clear signature of a heliospheric current sheet crossing as evidenced by enhancements in low first ionization potential (FIP) elements, ion charge state ratios, proton density, low Alfvénicity, and polarity estimates validates the combination of modeling, data, and mapping. We identify two FSW streams emerging from small equatorial CHs with low ion charge state ratios, low FIP bias, high Alfvénicity, and low footpoint brightness, yet anomalously low alpha particle abundance for both streams. We identify high-Alfvénicity slow solar wind emerging from the overexpanded boundary of a CH having intermediate alpha abundance, high Alfvénicity, and dips in ion charge state ratios corresponding to CH boundaries. Through this comprehensive analysis, we highlight the power of multi-instrument conjunction studies in assessing the sources of the solar wind. [ABSTRACT FROM AUTHOR]

Background: Diffusing alpha‐emitters radiation therapy ("Alpha‐DaRT") is a new method for treating solid tumors with alpha particles, relying on the release of the short‐lived alpha‐emitting daughter atoms of radium‐224 from interstitial sources inserted into the tumor. Alpha‐DaRT tumor dosimetry is governed by the spread of radium's progeny around the source, as described by an approximate framework called the "diffusion‐leakage model". The most important model parameters are the diffusion lengths of radon‐220 and lead‐212, and their estimation is therefore essential for treatment planning. Purpose: Previous works have provided initial estimates for the dominant diffusion length, by measuring the activity spread inside mice‐borne tumors several days after the insertion of an Alpha‐DaRT source. The measurements, taken when lead‐212 was in secular equilibrium with radium‐224, were interpreted as representing the lead‐212 diffusion length. The aim of this work is to provide first experimental estimates for the diffusion length of radon‐220, using a new methodology. Methods: The diffusion length of radon‐220 was estimated from autoradiography measurements of histological sections taken from 24 mice‐borne subcutaneous tumors of five different types. Unlike previous studies, the source dwell time inside the tumor was limited to 30 min, to prevent the buildup of lead‐212. To investigate the contribution of potential non‐diffusive processes, experiments were done in two sets: fourteen in vivo tumors, where during the treatment the tumors were still carried by the mice with active blood supply, and 10 ex‐vivo tumors, where the tumors were excised before source insertion and kept in a medium at 37∘C$37^\circ {\text{C}}$ with the source inside. Results: The measured diffusion lengths of radon‐220, extracted by fitting the recorded activity pattern up to 1.5 mm from the source, lie in the range 0.25−0.6mm${0.25-0.6}\nobreakspace {\text{mm}}$, with no significant difference between the average values measured in in‐vivo and ex‐vivo tumors: LRnin−vivo=0.40±0.08mm$L_{Rn}^{in-vivo}=0.40{\pm }0.08\nobreakspace {\text{mm}}$ versus LRnex−vivo=0.39±0.07mm$L_{Rn}^{ex-vivo}=0.39{\pm }0.07\nobreakspace {\text{mm}}$. However, in‐vivo tumors display an enhanced spread of activity 2–3 mm away from the source. This effect is not explained by the current model and is much less pronounced in ex‐vivo tumors. Conclusions: The average measured radon‐220 diffusion lengths in both in‐vivo and ex‐vivo tumors are consistent with published data on the diffusion length of radon in water and lie close to the upper limit of the previously estimated range of 0.2−0.4mm$0.2-0.4\nobreakspace {\text{mm}}$. The observation that close to the source there is no apparent difference between in‐vivo and ex‐vivo tumors, and the good agreement with the theoretical model in this region suggest that the spread of radon‐220 is predominantly diffusive in this region. The departure from the model prediction in in‐vivo tumors at large radial distances may hint at potential vascular contribution, which will be the subject of future works. [ABSTRACT FROM AUTHOR]

Background: Actinium‐225 (225Ac) is an alpha emitting radionuclide which has demonstrated promising results in Targeted Alpha Therapy (TAT). A concern with 225Ac is that the decay energy can break the bond to the targeting vehicle, resulting in the release of free alpha‐emitting daughter radionuclides in the body. Purpose: The aim of this work is to develop a compartment model to describe the movement of unlabeled 225Ac in a human where the daughter isotopes of 225Ac have unique biokinetics. Method: The ICRP Occupational Intake of Radionuclides reports were used to construct a compartment model for the 225Ac decay chain where the daughter isotopes of 225Ac are assigned their own unique transfer coefficients (TCs) between compartments. Computer simulations were performed for unlabeled 225Ac uniformly placed in the plasma and only the dose from alpha particles was considered. Absorbed doses to normal organs were determined for the liver, kidneys, bone, soft tissue, active marrow, and blood. Simulations were performed for the case when: (1) the daughters have unique biokinetics and (2) the daughters decay at the site of 225Ac. Results: When the daughters have unique biokinetics, the organs that receive the highest absorbed dose are the liver (male: 1466.6 mGy/MBq, female: 1885.7 mGy/MBq), bone (male: 293.6 mGy/MBq, female: 403.6 mGy/MBq) and kidneys (male: 260.8 mGy/MBq, female: 294.0 mGy/MBq). These doses were compared to the case when the daughters of 225Ac decay at the site of 225Ac. There was a 13.5% increase in kidney dose, a 0.8% decrease in liver dose, and <0.1% decrease in bone dose calculations when the daughters have unique biokinetics compared to assuming the daughters decay at the site of 225Ac. Conclusions: The kidneys received a large dose estimate (260‐295 mGy/MBq) as well as a considerable change in dose of +13.5% when the daughters have unique biokinetics compared to assuming the daughters decay at the site of 225Ac. Therefore, to accurately determine the kidney dose from unlabeled 225Ac in a human, the biokinetics of the daughter isotopes should be considered. [ABSTRACT FROM AUTHOR]

Computer experiments are performed on total cross sections for capture of both electrons from helium targets at 100-10000 keV. Employed are four quantum-mechanical perturbative four-body distorted wave methods (one of the first and three of the second order). The goal is to determine the cross section sensitivity to the perturbation strengths in distorted waves from the second-order methods. The perturbation strength is parametrized by the Sommerfeld factor (the quotient of the nuclear charge and the relative velocity of the colliding particles). At each fixed impact energy, the sought sensitivity is monitored by gradually modifying the nuclear charges in the Sommerfeld factors. These factors reside in the Coulomb distortions of the unperturbed channels states. The focus is on the electronic distortions through the eikonal Coulomb logarithmic phases and the full Coulomb waves. The logarithmic phases are the constituents of the compound phases for the net charges of the two heavy scattering aggregates in relative motions. A striking perturbation strength sensitivity of the obtained total cross sections is recorded. [ABSTRACT FROM AUTHOR]

Introduction: This article presents data on the ecological situation of agricultural territories where small cattle are raised, focusing on the exposure dose rate, radon concentration in residential and social buildings, and the density of alpha and beta particle flux. The study also examines the levels of heavy metals (Pb, Cd, As, Hg) and radionuclides Cs-137 and Sr-90 in raw meat from ecologically unfavorable areas, as well as the effects of heat treatment on reducing the content of these harmful substances. Methods: The research involved analyzing raw meat samples from the Abai district near the former Semipalatinsk Nuclear Test Site in Semey, Kazakhstan. The levels of heavy metals and radionuclides were measured before and after heat treatment to assess the effectiveness of cooking in reducing these contaminants. Radioecological measurements were also conducted in residential and social buildings to evaluate radon concentration and alpha and beta particle flux. Results and discussion: The results of the study showed a significant decrease in the levels of lead, cadmium, arsenic, Cs-137, and Sr-90 in meat after heat treatment. Prolonged cooking or quenching led to the most significant reductions in toxicity and radionuclides. These findings suggest that heat treatment can be an effective method for reducing the levels of harmful substances in meat from ecologically compromised areas. Further research is needed to explore other potential strategies for mitigating the impact of environmental contamination on food safety in agricultural regions. [ABSTRACT FROM AUTHOR]

The angular dependence of the alignment of the O(3 , 6.13 MeV) nucleus formed in the O( , ) O(3 ) and N( , ) O(3 ) reactions at -particle energies of 30.3 MeV is calculated taking into account the reactions' mechanisms that determine the cross section for the formation of the O(3 ) nucleus and is compared with the experimental values of the alignments reconstructed from the measured functions of angular correlations. It is established that the formation mechanisms of the O(3 ) nucleus significantly affect its orientation characteristics. The maximum amplitude alignment of the O(3 ) nucleus in both reactions is observed in the region of final particle emission angles in which direct mechanisms make the main contribution. At these angles, the calculated alignments are in satisfactory agreement with the experimental ones. [ABSTRACT FROM AUTHOR]

In modeling the charged alpha particle transport in hot-spot plasmas of inertial confinement fusion, the energy-losing rate is a major concern in the Monte Carlo simulations of alpha particle transport of a radiative-hydrodynamic code. However, the traditionally used energy stopping-power only describes the averaged energy-losing rate of the incident charged particles, whereas the variance of the energy exchange with the background particles is generally ignored. In this paper, the variance of charged particle collisions is studied by both analytical derivation and Monte Carlo simulations. An expression of the divergence of the charged particle energy-losing rate is given for the first time, which can be directly used for practical estimations. It indicates that when the areal density of the target particles along the incident particle path length is low, the divergence of the lost energy would be much larger than the average value, and the traditionally used energy stopping-power would be no longer sufficient to describe the charged particle Coulomb collisions. It helps to obtain a more comprehensive understanding about the charged particle transport in plasmas. [ABSTRACT FROM AUTHOR]

Data on Stark broadening parameters, spectral line widths, and shifts for 15 multiplets of N VI, whose spectral lines are broadened by collisions with electrons, protons, alpha particles (He III) and B III, B IV, B V and B VI ions, are presented. They have been calculated using the semiclassical perturbation theory, for temperatures from 50,000 K to 2,000,000 K, and perturber densities from 1016 cm−3 up to 1024 cm−3. The data for e, p and He III are of particular interest for the analysis and modelling of atmospheres of hot and dense stars, as, e.g., white dwarfs, and for investigation of their spectra, and data for boron ions are used for analysis and modelling of laser-driven plasma in proton–boron fusion research. Dataset: The dataset is submitted as a Supplementary File. Dataset License: CC-BY 4.0 [ABSTRACT FROM AUTHOR]

Extensive air showers (EAS), cascades of electromagnetic radiation and ionized particles produced when primary cosmic rays (CRs) interact with atmospheric nuclei, generate a plethora of secondary particles, including electrons, muons, alpha particles, X-rays, and neutrons. These phenomena, pivotal in the exploration of high-energy CR interactions, have prompted advancements in simulating the lateral distribution function (LDF) of secondary particles. Utilizing AIR-shower extended simulations (AIRES) software (version 19.04.10), this study presents simulations of EAS to elucidate the impact on the LDF at the high energy thresholds of 1016, 1018 and 1019 eV. The focus is on secondary muons and electrons, considering the influence of primary protons and iron nuclei across zenith angles of 0°, 20°, and 40°. Through the application of an exponential function model, novel coefficients were derived, reflecting the variation of the LDF relative to the distance from the shower core. These coefficients are instrumental in astrophysics and particle physics, offering a nuanced understanding of CR interactions with earth's atmosphere. By delineating the spatial particle distribution during interactions, insights into the shower's lateral extent and configuration are gleaned, facilitating the deduction of the initiating CR's energy. Such knowledge is crucial for CR spectrum analysis. The investigation of electron and muon LDFs not only advances fundamental particle physics but also holds implications for space exploration, radiation protection, and other domains. [ABSTRACT FROM AUTHOR]

Solution grown metal halide perovskites (MHPs) are a class of low-cost, direct conversion semiconducting materials with the potential to meet the need for large areas, high stopping power, and high sensitivity x-ray detectors. While polycrystalline MHP thin films have shown significant potential for meeting this need, their efficiencies for detecting x rays are limited by their thickness. This article presents an MHP variant, methylammonium lead tribromide (MAPB) in the form of 3D polycrystalline mosaic wafers with relatively high hole transport properties that demonstrated stable sensitivity during irradiation. An expedited and efficient detector fabrication method that did not include polishing or sintering was evaluated, and a radiograph of a brass key was produced using electron collection from the resulting wafer. However, a high dose rate was required due to very low sensitivity values. The effects of surface inhomogeneity and radiation damage were investigated as explanatory factors, and these phenomena were further characterized through IV measurements, current response as a function of electric field and x-ray dose rate, and alpha particle irradiation. The results indicated that although compromising surface quality for fabrication efficiency was the primary hindrance to the x-ray detection performance of 3D polycrystalline MAPB, stable performance could still be achieved under reasonable dose rates. [ABSTRACT FROM AUTHOR]

Surface α-particle emissivity testing and spectral characterization of two leaded tin spheres (Sn10%Pb90%, Sn63%Pb37%) and one lead-free tin sphere (Sn96.5%Ag3.0%Cu0.5%, SAC305) were carried out. The results show that Sn10%Pb90% Sn spheres have the highest α-particle emissivity; Sn63%Pb37% Sn spheres are the next highest, which is an order of magnitude lower than the α-particle emissivity of Sn10%Pb90% Sn spheres; and SAC305 Sn spheres have the lowest emissivity, which is reduced by about 55.6% compared to the emissivity of Sn63%Pb37% Sn spheres. All three types of tin spheres, after purification treatment, achieved the grade of ultra-low alpha particle emissivity (<0.002 α/(cm2·h)). The internal radionuclide traceability of the tin sphere, combined with the energy spectrum, reveals that the emission spectrum of the tin sphere exhibits an obvious "single peak" characteristic, with the peak energy in the interval of 5 MeV~5.5 MeV. Comparative analyses revealed that 210Po is the main nuclide that produces alpha particles, and 210Po originates from the decay of 210Pb. Further Monte Carlo simulations show that α-particles with energies greater than 4.1 MeV in the measured energy spectrum all come from the contribution of radionuclides within 5 μm of the surface layer of the tin sphere, which accounts for 60% of the total radioactivity. Combining the experimental and simulation results, it is found that the internal radionuclides of the tin sphere are characterized by more surface layer and less internal layer. The above results are of great significance for the establishment of α-particle mitigation methods for tin spheres. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of alpha particle irradiation on the optical characteristics of zinc oxide (ZnO) thin films, which were produced using various concentrations. A zinc oxide thin film was fabricated using the chemical bath deposition (CBD) technique, and glass was selected as the substrate material. A 5 MeV alpha particle beam was emitted during the irradiation process, created by a 241-Americium source. The optical properties of ZnO films within the wavelength range of 200 to 800 nm was measured using a UV-Vis spectrophotometer. The Fourier transform infrared (FTIR) spectrum exhibits a distinct peak at 490 cm-1, characteristic of zinc oxide (ZnO). Increasing the duration of alpha particle irradiation leads to a significant increase in intensity while causing only a slight alteration in the peak at 2500 cm-1. Optical measurement revealed a decrease in the direct energy band gaps as the radiation doses increased. This trend was observed for different durations 20, 40, 60, 80, and 100 minutes and across various concentrations 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 M. The energy band gaps ranged from (3.48 - 3.12) eV, (3.02 - 2.61) eV, (3.25 - 2.84) eV, (3.01 - 2.69) eV, (2.65 - 2.32) eV. Similarly, the band gaps diminish as the irradiation doses increase at various durations and concentrations. Additionally, the energy is likewise characterized as indirect. The energy ranges are as follows: (3.74 - 3.52) eV, (3.63 - 3.37) eV, (3.58 - 3.26) eV, (3.49 - 3.25) eV, (3.47 - 3.20) eV, and (3.42 - 3.20) eV. Our research revealed that the most favorable and smallest direct energy gap value ranges from 2.65 to 2.32 eV, while the indirect energy gap value ranges from 3.42 to 3.20 eV. These optimal values were seen at a concentration of 0.5 M, and the ideal irradiation time was determined to be 100 minutes. The energy gap for direct and indirect transitions can be reduced by increasing the concentration of alpha particle irradiation during the growth of ZnO nanotubes using the CBD method. These nanotubes have potential use in nano-photodetectors. [ABSTRACT FROM AUTHOR]

Background: Diffusing alpha‐emitters radiation therapy (DaRT) is a novel brachytherapy technique that leverages the diffusive flow of 224Ra progeny within the tumor volume over the course of the treatment. Cell killing is achieved by the emitted alpha particles that have a short range in tissue and high linear energy transfer. The current proposed absorbed dose calculation method for DaRT is based on a diffusion‐leakage (DL) model that neglects absorbed dose from beta particles. Purpose: This work aimed to couple the DL model with dose point kernels (DPKs) to account for dose from beta particles as well as to consider the non‐local deposition of energy. Methods: The DaRT seed was modeled using COMSOL multiphysics and the DL model was implemented to extract the spatial information of the diffusing daughters. Using Monte–Carlo (MC) methods, DPKs were generated for 212Pb, 212Bi, and their progenies since they were considered to be the dominant beta emitters in the 224Ra radioactive decay chain. A convolution operation was performed between the integrated number densities of the diffusing daughters and DPKs to calculate the total absorbed dose over a 30‐day treatment period. Both high‐diffusion and low‐diffusion cases were considered. Results: The calculated DPKs showed non‐negligible energy deposition over several millimeters from the source location. An absorbed dose >10 Gy was deposited within a 1.8 mm radial distance for the low diffusion case and a 2.2 mm radial distance for the high diffusion case. When the DPK method was compared with the local energy deposition method that solely considered dose from alpha particles, differences above 1 Gy were found within 1.3 and 1.8 mm radial distances from the surface of the source for the low diffusion and high diffusion cases, respectively. Conclusions: The proposed method enhances the accuracy of the dose calculation method used for the DaRT technique. [ABSTRACT FROM AUTHOR]

The question of whether the high U and Th concentrations in zircon are primary or secondary is often difficult to resolve, and a clear understanding of the modification processes of secondary U- and Thrich zircon is lacking. Zircon crystals from two well-studied, highly evolved granites, the Jiangjunshan muscovite granite in the Chinese Altai Mountains and the Cuonadong leucogranite in the Eastern Tethyan Himalaya, have been investigated and classified into two types. Type I exhibits typical igneous growth zoning, and type II has "diffuse" or "spongy" internal structures. These textures, along with compositional data, indicate that the type II zircon crystals formed through hydrothermal modification of magmatic zircon (type I) by infiltrating hydrothermal fluids. During hydrothermal modification, the U and Th concentrations increase from type I to type II in the Jiangjunshan muscovite granite but decrease from type I to type II in the Cuonadong leucogranite. The Raman spectra of type II zircon crystals from Jiangjunshan muscovite granite have broader peaks (i.e., measured as the full width at half maximum, FWHM) with decreased intensities than their type I counterparts, which indicates that the former are affected by significant accumulated radiation damage. However, the preserved radiation damage in both the type I and II zircon measured by Raman spectroscopy is less than that expected from the total dose of alpha particles calculated from the U and Th contents, which indicates variable degrees of annealing. We propose that late magmatic-hydrothermal alteration was responsible for the modification of magmatic zircon grains in highly evolved granites and resulted in the enrichment or redistribution of U and Th. The calculated radiation dose of the Cuonadong leucogranite zircon is far below that required for metamictization, which indicates that metamictization is not always responsible for diffuse and spongy textures. [ABSTRACT FROM AUTHOR]

Observational data at heliocentric distances of tens of solar radii suggest that fast magnetosonic modes make up a considerable fraction of the solar wind fluctuations. Furthermore, this fraction appears to increase closer to the Sun. We carry out three-dimensional kinetic simulations with particle ions and fluid electrons to evaluate the proton and alpha-particle heating produced by the damping of the fast waves in the solar corona. Realistic parameters at 5 solar radii, including the fluctuation amplitude, are used. We show that, due to the cyclotron resonance, the alphas are heated preferentially perpendicularly to the magnetic field and much more strongly than the protons. The presence of the alpha particles alters the energy partition by reducing the heating of the protons. Nevertheless, the proton heating is sufficient to account for the solar wind acceleration. [ABSTRACT FROM AUTHOR]

We report the results of the second charged-particle transport coefficient code comparison workshop, which was held in Livermore, California on 24–27 July 2023. This workshop gathered theoretical, computational, and experimental scientists to assess the state of computational and experimental techniques for understanding charged-particle transport coefficients relevant to high-energy-density plasma science. Data for electronic and ionic transport coefficients, namely, the direct current electrical conductivity, electron thermal conductivity, ion shear viscosity, and ion thermal conductivity were computed and compared for multiple plasma conditions. Additional comparisons were carried out for electron–ion properties such as the electron–ion equilibration time and alpha particle stopping power. Overall, 39 participants submitted calculated results from 18 independent approaches, spanning methods from parameterized semi-empirical models to time-dependent density functional theory. In the cases studied here, we find significant differences—several orders of magnitude—between approaches, particularly at lower temperatures, and smaller differences—roughly a factor of five—among first-principles models. We investigate the origins of these differences through comparisons of underlying predictions of ionic and electronic structure. The results of this workshop help to identify plasma conditions where computationally inexpensive approaches are accurate, where computationally expensive models are required, and where experimental measurements will have high impact. [ABSTRACT FROM AUTHOR]

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The design of semiconductor-based heterojunction structures can be turned useful to raise the efficiency of nuclear micro-batteries. In this study, we have investigated a micro-power alphavoltaic battery by using a lab-made software. The nuclear battery consists of an In0.49Ga0.51P/GaAs heterostructure irradiated by americium-241 (Am241) alpha particles with an average kinetic energy of 5.485 MeV. The alphavoltaic battery exhibits an overall active area of 1 cm². Based on a comprehensive analytical model, the device current density-voltage J(V) and output electric power P(V) characteristics are simulated extracting the energy conversion efficiency. The model takes into account the reflection of the incident alpha particles, the ohmic losses, the effect of the boundary between the two layers, and the depletion region borders. Different values of the radioisotope apparent activity density, the emitter and base dopant concentrations, and the surface recombination velocities in both the front and back layers are considered during the simulations to optimize the battery performance. The present study reports that by irradiating by a 2.4 mCi/cm² Am241 source, the obtained energy conversion efficiency of the battery can reach 10.31% with a maximum output power density of 16.07 μW/cm². Therefore, In0.49Ga0.51P/GaAs heterostructure coupled with Am241 seems a promising design for long- term energy supply in harsh environments. [ABSTRACT FROM AUTHOR]

This article discusses the use of silicon carbide (SiC) as a semiconductor material for radiation detectors. SiC has several advantages over conventional materials, including a wider bandgap, higher breakdown field, and higher thermal conductivity. The article describes the fabrication of SiC detectors and their performance in detecting alpha particles, X-rays, beta particles, and neutrons. It also mentions the successful application of SiC sensors in a radiation camera for X-ray imaging and particle tracking. The article concludes that SiC shows great promise as a semiconductor material for radiation detection. [Extracted from the article]

Purpose: Cancer treatment with alpha-emitter-based radioligand therapies (α-RLTs) demonstrates promising tumor responses. Radiolabeled peptides are filtered through glomeruli, followed by potential reabsorption of a fraction by proximal tubules, which may cause acute kidney injury (AKI) and chronic kidney disease (CKD). Because tubular cells are considered the primary site of radiopeptides' renal reabsorption and potential injury, the current use of kidney biomarkers of glomerular functional loss limits the evaluation of possible nephrotoxicity and its early detection. This study aimed to investigate whether urinary secretion of tubular injury biomarkers could be used as an additional non-invasive sensitive diagnostic tool to identify unrecognizable tubular damage and risk of long-term α-RLT nephrotoxicity. Methods: A bifunctional cyclic peptide, melanocortin 1 ligand (MC1L), labeled with [203Pb]Pb-MC1L, was used for [212Pb]Pb-MC1L biodistribution and absorbed dose measurements in CD-1 Elite mice. Mice were treated with [212Pb]Pb-MC1L in a dose-escalation study up to levels of radioactivity intended to induce kidney injury. The approach enabled prospective kidney functional and injury biomarker evaluation and late kidney histological analysis to validate these biomarkers. Results: Biodistribution analysis identified [212Pb]Pb-MC1L reabsorption in kidneys with a dose deposition of 2.8, 8.9, and 20 Gy for 0.9, 3.0, and 6.7 MBq injected [212Pb]Pb-MC1L doses, respectively. As expected, mice receiving 6.7 MBq had significant weight loss and CKD evidence based on serum creatinine, cystatin C, and kidney histological alterations 28 weeks after treatment. A dose-dependent urinary neutrophil gelatinase-associated lipocalin (NGAL, tubular injury biomarker) urinary excretion the day after [212Pb]Pb-MC1L treatment highly correlated with the severity of late tubulointerstitial injury and histological findings. Conclusion: Urine NGAL secretion could be a potential early diagnostic tool to identify unrecognized tubular damage and predict long-term α-RLT-related nephrotoxicity. [ABSTRACT FROM AUTHOR]

Purpose: Current treatments for osteosarcoma (OS) have a poor prognosis, particularly for patients with metastasis and recurrence, underscoring an urgent need for new targeted therapies to improve survival. Targeted alpha-particle therapy selectively delivers cytotoxic payloads to tumors with radiolabeled molecules that recognize tumor-associated antigens. We have recently demonstrated the potential of an FDA approved, humanized anti-GD2 antibody, hu3F8, as a targeted delivery vector for radiopharmaceutical imaging of OS. The current study aims to advance this system for alpha-particle therapy of OS. Methods: The hu3F8 antibody was radiolabeled with actinium-225, and the safety and therapeutic efficacy of the [225Ac]Ac-DOTA-hu3F8 were evaluated in both orthotopic murine xenografts of OS and spontaneously occurring OS in canines. Results: Significant antitumor activity was proven in both cases, leading to improved overall survival. In the murine xenograft's case, tumor growth was delayed by 16–18 days compared to the untreated cohort as demonstrated by bioluminescence imaging. The results were further validated with magnetic resonance imaging at 33 days after treatment, and microcomputed tomography and planar microradiography post-mortem. Histological evaluations revealed radiation-induced renal toxicity, manifested as epithelial cell karyomegaly and suggestive polyploidy in the kidneys, suggesting rapid recovery of renal function after radiation damage. Treatment of the two canine patients delayed the progression of metastatic spread, with an overall survival time of 211 and 437 days and survival beyond documented metastasis of 111 and 84 days, respectively. Conclusion: This study highlights the potential of hu3F8-based alpha-particle therapy as a promising treatment strategy for OS. [ABSTRACT FROM AUTHOR]

Background: Diffusing alpha‐emitters Radiation Therapy ("Alpha DaRT") is a new technique that enables the use of alpha particles for the treatment of solid tumors. Alpha DaRT employs interstitial sources carrying a few μ$\mu$Ci of 224$^{224}$Ra below their surface, designed to release a chain of short‐lived atoms (progeny of 224$^{224}$Ra) which emit alpha particles, along with beta, Auger, and conversion electrons, x‐ and gamma rays. These atoms diffuse around the source and create—primarily through their alpha decays—a lethal high‐dose region measuring a few millimeters in diameter. Purpose: While previous studies focused on the dose from the alpha emissions alone, this work addresses the electron and photon dose contributed by the diffusing atoms and by the atoms remaining on the source surface, for both a single Alpha DaRT source and multi‐source lattices. This allows to evaluate the low‐LET contribution to the tumor dose and tumor cell survival, and demonstrate the sparing of surrounding healthy tissue. Methods: The low‐LET dose is calculated using the EGSnrc and FLUKA Monte Carlo (MC) codes. We compare the results of a simple line‐source approximation with no diffusion to those of a full simulation, which implements a realistic source geometry and the spread of diffusing atoms. We consider two opposite scenarios: one with low diffusion and high 212$^{212}$Pb leakage, and the other with high diffusion and low leakage. The low‐LET dose in source lattices is calculated by superposition of single‐source contributions. Its effect on cell survival is estimated with the linear quadratic model in the limit of low dose rate. Results: For sources carrying 3 μ$\umu$Ci/cm 224$^{224}$Ra arranged in a hexagonal lattice with 4 mm spacing, the minimal low‐LET dose between sources is ∼18−30$\sim 18-30$ Gy for the two test cases and is dominated by the beta contribution. The low‐LET dose drops below 5 Gy ∼3$\sim 3$ mm away from the outermost source in the lattice with an effective maximal dose rate of <0.04$<0.04$ Gy/h. The accuracy of the line‐source/no‐diffusion approximation is ∼15%$\sim 15\%$ for the total low‐LET dose over clinically relevant distances (2–4 mm). The low‐LET dose reduces tumor cell survival by a factor of ∼2−200$\sim 2-200$. Conclusions: The low‐LET dose in Alpha DaRT can be modeled by conventional MC techniques with appropriate leakage corrections to the source activity. For 3 μ$\umu$Ci/cm 224$^{224}$Ra sources, the contribution of the low‐LET dose can reduce cell survival inside the tumor by up to two orders of magnitude. The low‐LET dose to surrounding healthy tissue is negligible. Increasing source activities by a factor of 5 can bring the low‐LET dose itself to therapeutic levels, in addition to the high‐LET dose contributed by alpha particles, leading to a "self‐boosted" Alpha DaRT configuration, and potentially allowing to increase the lattice spacing. [ABSTRACT FROM AUTHOR]

High radiation resistance, chemical inertness, the ability to operate at elevated temperatures, high mobility and efficiency of charge-carrier collection are important properties of diamond for designing detectors and spectrometers of ionizing radiation. Currently, diagnostics of neutrons and neutral particle fluxes based on diamond detectors for the ITER thermonuclear reactor are justified and developed. This work presents the results of a Raman spectroscopy and photoluminescence spectroscopy study of the electronic quality of synthesized epitaxial diamond films obtained by vapor deposition in a hydrogen and methane mixture in the ARDIS reactor on boron-doped single-crystal diamond substrates. To confirm their electronic quality, detectors have been made from films selected by spectrometric methods and the charge collection efficiency and energy resolution have been measured when irradiated with alpha particles from a 241Am source and 14.7 MeV fast neutrons from the ING-07T2 neutron generator. [ABSTRACT FROM AUTHOR]

The alpha particle distribution in the full energy region is studied in this work. The Fokker–Planck equation near the equilibrium state is analytically solved using an iteration method for alpha particles. The resulting distribution includes the Maxwellian part, the modified slowing down part, and the high energy tail part. The analytical results align with the conventional slowing down distribution in the high energy region v α > 0.2 v b and the Maxwellian distribution in the low energy region v α < 0.1 v b , where v α is the alpha particle velocity and vb is the birth velocity of alpha particles. In the range of 0.1 v b < v α < 0.2 v b , the distribution is described by the sum of the Maxwellian part and modified slowing down part. Turbulent transport effects on the alpha particle distribution are studied through introducing a local sink term. A simplified analytical solution is provided, and the bump-on-tail distribution is observed under appropriate parameters. In both cases with and without transport effects, the Fokker–Planck equation is numerically solved. It is shown that the full temporal evolution of the system can be divided into three stages: the slowing down stage, thermalization stage, and quasi-steady state stage. The numerically obtained alpha particle distribution in the quasi-steady state stage agrees well with the theoretical results. [ABSTRACT FROM AUTHOR]

The article titled "Megalomania and Microphilia" by Vilém Flusser discusses the limitations of human experience in terms of dimensions. Flusser argues that our range of experience is narrow compared to the supposedly unlimited and infinitely divisible scale of dimensions. He explores the problems that arise when we extend our dimensions through tools like microscopes and scientific theories, suggesting that this extension dilutes our experience and introduces imaginary and conceptual characteristics. Flusser concludes that science dehumanizes by diluting our experience, but also humanizes by allowing us to overcome our circumstances. [Extracted from the article]

A thorough understanding of collisionless shocks requires knowledge of how different ion species are accelerated across the shock. We investigate a bow shock crossing using the Magnetospheric Multiscale spacecraft after a coronal mass ejection crossed Earth, which led to solar wind consisting of protons, alpha particles, and singly charged helium ions. The three species are resolved upstream of the shock. The low Mach number of the bow shock enabled the ions to be partly distinguished downstream of the shock due to the relatively low ion heating. Some of the protons are specularly reflected and produce quasi-periodic fine structures in the velocity distribution functions downstream of the shock. Heavier ions are shown to transit the shock without reflection. However, the gyromotion of the heavier ions partially obscures the fine structure of proton distributions. Additionally, the calculated proton moments are unreliable when the different ion species are not distinguished by the particle detector. The need for high time-resolution mass-resolving ion detectors when investigating collisionless shocks is discussed. [ABSTRACT FROM AUTHOR]

GaN devices play a major role in modern electronics, providing high-power handling, efficient high-frequency operation, and resilience in harsh environments. However, electric field crowding at the edge of the anode often limits its full potential, leading to single-event effects (SEEs) at lower bias voltages under heavy ion radiation. Here, we report on the performance of homojunction GaN vertical PiN diodes with a hybrid edge termination design under heavy ion irradiation, specifically, oxygen ions, chlorine ions, Cf-252 fission fragments, and alpha particles from an Am-241 source. The unique hybrid edge termination (HET) design provides better electric field management, preventing breakdown from occurring at the edge of the anode at lower voltages. The results of this study reveal that these devices exhibit excellent tolerance to 12-MeV oxygen and 16-MeV chlorine ions, owing to their low linear energy transfer (LET) and range in GaN. However, single-event burnout (SEB) is observed during the Cf-252 exposure at about 50% of the diodes' electrical breakdown voltage due to the presence of higher LET and longer-range ions. Optical and scanning electron microscopy (SEM) reveal that the damage that caused by SEB lies close to the center of these devices rather than the anode edge. Devices with junction termination extension (JTE) instead of HET edge termination also show similar SEB when irradiated with Cf-252 fission fragments. Physical damage due to SEB occurs at the edge of the anode for these devices. These comparative results show the benefits of HET for enhancing the resistance of GaN-based PiN diodes to heavy ion irradiation. [ABSTRACT FROM AUTHOR]

The properties of minor ions in the solar wind are important indicators of the state of the solar corona and the heating processes it undergoes as it expands. Evidence of preferential heating of minor ions has been observed in the solar wind, and is believed to be active up to a certain radial boundary, beyond which thermalization due to Coulomb collisions predominates. Building on previous works that calculated the location of this boundary for alpha particles, this work calculates the outer radial boundary of the zone of preferential heating for selected heavy ions in the solar wind. This analysis uses ion data from the Solar Wind Ion Composition Spectrometer and proton data from the Solar Wind Electron, Proton, and Alpha Monitor aboard the Advance Composition Explorer spanning the years from 1998 through to 2011. Observations of proton and ion temperatures, velocities, and densities, and fixed parameters derived from temperature, density, and velocity scaling laws are used in a model function to predict the radial boundary and excess temperature at the boundary via reduction of the χ 2/degrees of freedom statistic. In this study, the values of the radial boundary of the preferential heating zone were quite high when compared to what was previously found for alpha particles, but a clear scaling relationship between excess temperature and ion properties was observed. [ABSTRACT FROM AUTHOR]

The protection of first responders from radioactive contamination with alpha emitters that may result from a radiological accident is of great complexity due to the short range of alpha particles in the air of a few centimeters. To overcome this issue, for the first time, a system mounted on a UAS for the near-real-time remote measurement of alpha particles has been developed, tested, and calibrated. The new system, based on an optical system adapted to be installed on a UAS in order to measure the UV-C fluorescence emitted by alpha particles in the air, has been tested and calibrated, carried out in the laboratory and in field experiments using UV-C LEDs and 241Am sources. In experimental flights, the probability of detecting a point source was determined to be approximately 60%. In the case of a surface extended source, a detection efficiency per unit surface activity of 10 counts per second per MBq cm−2 was calculated. A background count rate of UV-C of around 26 ± 28 s−1 for an integration time of 0.1 s was measured during flights, which led to a decision threshold surface activity of 5 MBq cm−2. [ABSTRACT FROM AUTHOR]

Background: Diffusing alpha‐emitters Radiation Therapy ("DaRT") is a promising new modality for the treatment of solid tumors. Interstitial sources containing 224Ra are inserted into the tumor, producing alpha particles via the decay of 224Ra and its daughters. The alpha particles are able to produce a "kill region" of several mm due to the diffusion of the alpha‐emitting atoms. The Diffusion‐Leakage (D‐L) model has been proposed to describe the movement of the alpha‐emitters used in DaRT in tumor tissue. Purpose: To date, estimating the dose delivered under the D‐L model has been accomplished with numerical solutions based on finite difference methods, namely DART1D and DART2D, as well as with asymptotic expressions for the long time limit. The aim of this work is to develop a flexible method of finite elements for solving the D‐L model and to validate prior solutions of the D‐L model. Methods: We develop a two‐dimensional finite element solution to the D‐L model implemented using the FEniCS software library. Our approach solves the variational formulation of the D‐L equations on an unstructured mesh of triangular Lagrangian elements. We calculate the local dose in the mid‐ and axial planes of the source and validate our results against the one‐ and two‐dimensional solutions obtained using the previously proposed numerical scheme, DART1D and DART2D. We use our model to estimate the change in dose in the source midplane as a function of the physical parameters used in the D‐L model. Results: The local dose at the end of a 30 day treatment period estimated by our numerical method differs from DART1D and DART2D by less than 1% in the source midplane and less than 3% along the source axis over clinically relevant distances, with the largest discrepancies in high gradient areas where the Finite Element Method (FEM) mesh has a higher element density. We find that within current experimentally estimated ranges for D‐L model parameters, the dose in the source midplane at a distance of 2 mm can vary by over a factor of 3. Conclusions: The 2D finite element model reproduces the calculated dose obtained with DART1D and DART2D under the assumptions D‐L model. The variation in predicted dose within current experimental ranges for model parameters suggests the necessity of further studies to better determine their statistical distributions. Finally, the FEM model can be used to calculate dose from DaRT in a variety of realistic 2D geometries beyond the D‐L model. [ABSTRACT FROM AUTHOR]

In this paper, an overview of wide-bandgap (WBG) semiconductors for radiation detection applications is given. The recent advancements in the fabrication of high-quality wafers have enabled remarkable WBG semiconductor device applications. The most common 4H-SiC, GaN, and β-Ga2O3 devices used for radiation detection are described. The 4H-SiC and GaN devices have already achieved exceptional results in the detection of alpha particles and neutrons, thermal neutrons in particular. While β-Ga2O3 devices have not yet reached the same level of technological maturity (compared to 4H-SiC and GaN), their current achievements for X-ray detection indicate great potential and promising prospects for future applications. [ABSTRACT FROM AUTHOR]

The fragmentation of quasi-projectiles from the nuclear reaction 40 Ca+ 12 C at 25 MeV per nucleon bombarding energy was used to produce excited self-conjugate nuclei (from 16 O to 28 Si). Temperature and density conditions for alpha-clustering were determined. Measured temperatures have been found in the range of 5.5 - 6.0 MeV whereas density values of 0.3 - 0.4 times the saturation density are deduced. This density domain is also predicted by constrained self-consistent mean field calculations. At present such calculations are performed at zero temperatures and geometric alpha cluster configurations are observed: a tetrahedron for 16 O for example. Experimentally, by looking to 8 Be production from excited self-conjugate nuclei, a signature of final state interaction between two alpha-particles was evidenced. This indicates that, due to the temperature, geometric configurations are not the only ones present, which argues in favor of finite temperature calculations. [ABSTRACT FROM AUTHOR]

Within the two-channel distorted wave second-order perturbative theoretical formalism, we study capture of both electrons from helium-like targets by heavy nuclei as projectiles at intermediate and high impact energies. The emphasis is on the four-body single-double scattering (SDS-4B) method and the three-body continuum distorted wave impact parameter method (CDW-3B-IPM). The SDS-4B method deals with the full quantum-mechanical correlative dynamics of all the four interactively participating particles (two electrons, two nuclei). The CDW-3B-IPM is a semi-classical three-body independent particle model (one electron, two nuclei), using a combinatorial calculus to describe double capture by a product of two uncorrelated probabilities, integrated over impact parameters. Both theories share a common feature in having altogether two electronic full Coulomb continuum wave functions. One such function is centered on the projectile nucleus in the entrance channel, whereas the other is centered on the target nucleus in the exit channel. These two methods satisfy the correct initial and final Coulomb boundary conditions in the asymptotic region of scattering, at infinitely large inter-particle separations. Yet, it is presently demonstrated that most of the available experimental data on total cross sections for the double capture from helium by alpha particles distinctly favor the SDS-4B method. This is especially true at intermediate energies. Such energies are critically important in versatile applications under the general umbrella of ion transport in matter, including thermonuclear fusion (plasma physics) and ion therapy (medicine). [ABSTRACT FROM AUTHOR]

The present study, a zinc oxide (ZnO) thin films samples prepared using a Chemical bath deposition (CBD). On a glass base where the effect of irradiation with alpha particles on the optical properties of zinc oxide thin films prepared at a concentration of (0.3M) was studied. Irradiation was used from a alpha particle emitted from Americium (Am241) source,with average energy (5.486)MeV. The optical properties of ZnO films measured (200- 800nm) using a UV-Vis spectrophotometer.It was to study the relationship of absorbance as a function of photon energy for ZnO thin films.The energy gap for direct transition at standard was also calculated (2.49eV), while at irradiation of 20 min and 80 min, it was (2.37,2.29) eV, respectively. The energy band gap for indirect transfer was also calculated for the standard sample (3.26eV), while irradiation time at (20 and 80) min were (3.20,3.15) eV, respectively.The results for the research have confirmed that the direct and indirect energy gaps decrease with irradiation time when increases the time. The CBD method is used to obtain to ZnO nanotubes, which can be employed as photodetectors. [ABSTRACT FROM AUTHOR]