Alpha Particles Research Articles

The relationship between ceramic additives among structural, morphological, shielding, and stopping power features of BN/ZnFe metal matrix materials

Ionizing radiation has many negative effects on human health. These include eye and skin disorders and DNA damage inside cells. To eliminate or reduce these destructive effects of radiation, economical, low-corrosion, effective shielding materials with high absorption properties are needed. In this study, zinc-iron-based metal matrix composite materials with various proportions of boron nitride were produced on steel substrates. The structural and surface properties of the materials were examined with XRD and SEM images, respectively. These structures were irradiated with radioactive Am-241, Sr-90, Na-22, and Co-60 sources for their radiation shielding properties. Then, the absorption ratios in the samples were investigated according to the reinforced ceramic amounts in their content. In addition to the experiment, the stopping power and range values of the samples were calculated to check the reliability of the results. ZnFe alloys and composites are based on the dominant peaks of the heta (ƞ) phase of zinc. The amount of boron nitride added to the electrolyte significantly affected the crystal structure, while the incorporation of boron nitride into the zinc-iron matrix impressed the average grain size of the coating. The microstrain and dislocation densities of the film first decreased to 15 g/L and then increased depending on the ion diameter. The BN doping made the porous surface smooth, crack-free, and compact. It was found that the absorption rates for radiation increased as the amount of boron nitride in the samples increased. According to the rising amount of boron nitride, the absorption percentages are between 1.88 and 6.19% for alpha particles, 0.78–3.06% for electrons, 0.77–6.56% for positrons, and 0.61–6.34% for gamma photons. When the stopping power and range values were averaged, the amount of boron nitride increased directly and inversely with the stopping power and range values, respectively.

Research on Detection Efficiency of Imaging Plates for Alpha Particles Using Two Types of Imaging Plate.

Imaging plates can measure isotopes with alpha decay (such as radon and its progeny, americium, and so on). However, the detection efficiency of imaging plates is affected by alpha particle energy, types of imaging plates, and the overlapping effect. In this study, simulations were performed to analyze the relationship between detection efficiency and these three influence factors. The research findings suggest that BAS-TR and BAS-MS are well-suited for the detection of alpha particles with energy levels below 6.83 MeV and above, respectively. The track overlap effect correction method proposed in this study is applicable to both BAS-TR and BAS-MS image plates. The measurement results of radon progeny demonstrate that the correction method enhances the detection efficiency from 0.203 to 0.288. This study presents a valuable approach for selecting the appropriate image plate and correcting the track overlap effect in the measurement of alpha radioactive material concentration and other related information.

Note on dose conversion for radon exposure

The epidemiological approach to converting radon exposure to effective dose is examined. Based on the definition of the effective dose, the dose conversion is obtained from the equivalence of lung-specific detriment associated with low-LET radiation and with radon exposure. This approach most reliably estimates effective dose per radon exposure on the basis of epidemiological data and implicitly includes the radiation weighting factor required to calculate the effective dose from radon exposure using the dosimetric approach, applying biokinetic and dosimetric models. Consistency between the results of the epidemiological and dosimetric approaches is achieved by using a radiation weighting factor of about 10 for alpha particles instead of the current ICRP value of 20. In contrast, the epidemiological approach implemented in ICRP 65, and referred to as dose conversion convention, was based on direct comparison of total radiation detriment with lung detriment from radon exposure. With the revision of radiation detriments in ICRP 103, this approach can be judged to overestimate the effective dose per radon exposure by about a factor of two because the tissue weighting factor for lung differs from the value of relative detriment to which it relates.

Optimizing the composition of barium-borate glasses for enhancing thermal neutron shielding efficiency: Monte Carlo simulation

A transparent window with thermal neutron shielding properties was an important part of the stations of the nuclear reactors and the particle accelerators. The borate glass with a high neutron cross section was a candidate as a glass network for the neutron shielding window. In order to slow down thermal neutrons, they were trapped by boron and subsequently emitted secondary radiation, such as alpha particles and gamma-ray radiation. This work was to optimize the content between a ratio of borate with a high cross-section neutron interaction and barium for shielding alpha and gamma ray. The barium-borate glasses were successfully synthesized using the melting technique in the atmosphere. Measurements of mechanical and optical glass properties were presented. The measured results showed that an increase in barium oxide content in the glass ratio enhanced the glass density and the transmittance at a visible wavelength. In the calculation of radiation shielding properties, FLUKA code based on Monte Carlo Simulation was demonstrated. The calculated results revealed that an increase in the barium oxide content in the glass composition reduced the thermal neutron shielding properties of the glass samples. In contrast, the glass with barium contents enhanced the photon-shielding efficiency, as indicated by the mass attenuation coefficient and half-value layer. Not only the ratio of the barium and borate contents affected the shielding properties, but the increased glass thickness also enhanced the shielding properties. Thus, the utilization of cooperative borate glasses and barium with appropriate thickness could potentially serve as a viable option for simultaneously protecting against thermal neutrons and photons. The barium-borate glasses with our composition might be used as a window in a thermal neutron station as well as for photon radiation.

Fast ion relaxation in ITER mediated by Alfvén instabilities

We address the critical issue for future burning plasmas of whether high-energy fusion products or auxiliary heating-beam ions will be confined for a sufficiently long time to compensate for thermal plasma energy losses. This issue can be mitigated by one of the most deleterious collective phenomena—the instability of low, sub-cyclotron frequency Alfvén eigenmodes (AEs), such as toroidicity-induced AEs and reversed-shear AEs in the ITER steady-state scenario. Using a revised quasi-linear (QL) theory applied to energetic particle (EP) relaxation in the presence of AEs, we find that the AE instabilities can affect both neutral beam ions and alpha particles, although the resulting fast ion transport is expected to be modest if classical particle slowing down is assumed. On the other hand, the QL theory predicts that the AE amplitudes will be enhanced by the background microturbulence, although this topic remains outside our scope due to the significant numerical effort required to evaluate these effects. We report our results for EP relaxation dynamics obtained utilizing several tools: (i) a comprehensive linear stability study of the sub-cyclotron Alfvénic spectrum as computed by ideal magnetohydrodynamic NOVA simulations for the AE eigenproblem, (ii) drift kinetic NOVA-C calculations for wave–particle interaction and AE growth/damping rates, and (iii) predictive QL modeling coupled with the global transport code TRANSP to assess the EP relaxation on the equilibrium timescale.

Transient behaviour analysis in silicon carbide alpha particle detector using TCAD and SRIM simulation

Time response characteristics of α particle detector are crucial for monitoring radiation fields varied with time and its characterization of pulse radiation field. Here, SRIM-informed TCAD simulation is utilized to visually investigate the transient behaviors of carriers and alpha particles in 4H-SiC Schottky barrier detectors for the time response characteristics. We identified external bias voltage and incident particle energy as key factors to influence transient current pulse broadening. Low-energy alpha particles result in low initial kinetic energy of the ionization-generated carriers, leading to transient current broadening and reduced time resolution characteristics. Conversely, high-energy alpha particles ionize carrier with high drift velocity, preventing the broadening effect. Our simulation provides a planform and valuable guidance for optimizing alpha particle detector, selecting appropriate bias voltages, and enhancing time resolution capabilities.

Advancements in Remote Alpha Radiation Detection: Alpha-Induced Radio-Luminescence Imaging with Enhanced Ambient Light Suppression.

Heavy nuclides like uranium and their decay products are commonly found in nuclear industries and can pose a significant health risk to humans due to their alpha-emitting properties. Traditional alpha detectors require close contact with the contaminated surface, which can be time-consuming, labour-intensive, and put personnel at risk. Remote detection is urgently needed but very challenging. To this end, a candidate detection mechanism is alpha-induced radio-luminescence. This approach uses the emission of photons from radio-ionised excited nitrogen molecules to imply the presence of alpha emitters from a distance. Herein, the use of this phenomenon to remotely image various alpha emitters with unparalleled levels of sensitivity and spatial accuracy is demonstrated. Notably, the system detected a 29 kBq Am-241 source at a distance of 3 m within 10 min. Furthermore, it demonstrated the capability to discern a 29 kBq source positioned 7 cm away from a 3 MBq source at a 2 m distance. Additionally, a 'sandwich' filter structure is described that incorporates an absorptive filter between two interference filters to enhance the ambient light rejection. The testing of the system is described in different lighting environments, including room light and inside a glovebox. This method promises safer and more efficient alpha monitoring, with applications in nuclear forensics, waste management and decommissioning.

Use of the OSCAR-Fusion V1.4.a code for a preliminary assessment of the ACP contamination within the main ITER water cooling circuit

One of the main objectives of ITER is to produce 500 MW of power from a deuterium-tritium plasma for several seconds. This goal presents two inherent challenges: firstly, in-vessel components will require active cooling to remove the heat coming from the fusion reaction (i.e., mainly fast neutrons and alpha particles). Secondly, the materials exposed to the neutron flux will yield activated corrosion products (ACPs) in all primary cooling circuits of ITER. From a safety point of view, ACPs are one of the contributors to the Occupational Radiation Exposure (ORE), they represent a source of radiological waste and also contribute to the source term for accidental scenarios involving the loss of primary confinement. Therefore, ACPs assessment is key to estimate radiological impact for nuclear workers and the public. ITER nuclear safety engineers adopted OSCAR-Fusion v1.4.a code to assess the ACPs inventory in the Integrated Blanket ELMs and Divertor (IBED) cooling loop. This paper describes the selection of input data, the modelling of the circuits and the operational scenarios used in OSCAR-Fusion calculations. This study also examines the outcomes of such calculations, notably in terms of ACPs inventory, emphasizing the impact on the ORE and highlighting its driving parameters. Additionally, the paper offers recommendations for better ACPs management in the context of the ITER project and in accordance with the ALARA principle.

Investigation of 209Bi (α,2n)211At reaction route for the production of α-emitter 211At

In this research, the calculations have been done for α-emitters of 211At, which is a promising isotope in cyclotrons for radiotherapy. The scope of the study is to investigate the production parameters of 211At, which can be produced in the cyclotron by bombarding bismuth with an alpha particle beam for the 209Bi(α,2n)211At reaction. The total activity, reaction yield, and production cross–sections of 209Bi(α,2n)211At reaction have been calculated by using diverse level density models of the TALYS 1.95 code. Furthermore, recommended data with 95% confidence limits have been obtained. Experimental data available in the literature based on EXFOR compilation are used to compare the findings. Consequently, the required beam energy has been found to be 28 MeV to produce 211At.

Measurement of Naturally-Occurring Radioactive Materials (NORM) using a scintillator-based alpha detector

It is important to differentiate between natural and artificial radioactive materials such as plutonium in nuclear facilities. In this study, a scintillator-based alpha-particle detector was developed using YAP:Ce scintillator and Multi-Anode PhotoMultiplier Tube. The detector was used to measure various naturally occurring radioactive materials (NORM) samples including radon progeny, lead plate, lantern mantle, and radium ceramic ball. The measurement results were compared with Monte Carlo simulation calculations and were found to be in agreement. The energy resolution of the detector is 8.6%FWHM. In the measurement results of radon progeny, peaks of 212Bi (6.1 MeV), 214Po (7.7 MeV), and 212Po (8.8 MeV) can be observed. The lead plate contains 210Po and emits 5.3 MeV alpha particle. The simulation with the same energy was able to reproduce the actual measurement. The results showed the energy and distribution of the alpha particles emitted by the NORM samples. The study successfully demonstrated the capability of the developed alpha-particle detector in identifying NORM.

The role of MoO3 on the physical, elasto-mechanical and nuclear shielding efficiency of barium-boro-bismuthate glass system: Comparative investigation

Investigations were conducted on the effect of molybdenum addition on the physical, elasto-mechanical and nuclear shielding characteristics of five different glasses, designated S1 through S5, with varying amounts of MoO3. The mechanical parameters of the examined glasses, including their Young (Y), bulk (B), shear (S) and longitudinal (L) moduli, microhardness (H), and poisons ratio, were calculated utilizing the Makishima-Mackenzie technique. The physical and mechanical characteristics of the examined glasses are improved by the addition of MoO3. The Y, B, S, and L moduli rose with increasing MoO3 concentrations from 34.6680 to 35.9989 GPa, 14.13578–14.664 GPa, 21.10714–22.60943 GPa, and 31.70897–33.59673 GPa, respectively. The H values of the glass network also dropped from 0.016431 to 0.016885 GPa. Moreover, as the concentration of MoO3 rose, the Poisson ratio value changed from 0.427021 to 0.429533. The MCNP5 code and WinXCOM program were used to compute various shielding parameters for X/gamma-rays in the energy range between 0.015 and 15 MeV. A good agreement was found between the estimated values using both MCNP5 code and WINXCOM program. The S5 glass sample exhibited the greatest gamma-ray attenuation characteristics among the examined glasses. When compared to other radiation shielding materials including recently studied glasses and polymers as well as other typical gamma ray shielding materials, the current glass composition offers complete (100 %) x-ray protection and effective efficacy for gamma-ray shielding at energies up to 15 MeV. Calculations were made of the studied glasses' macroscopic removal cross sections (∑R), which were then compared to those of commonly used neutron shielding materials. S1 sample performed the best ∑R value while S5 displays a value (0.10516 cm−1) that is comparable to those of graphite, concrete, basalt magnetite, and a few other recently studied glasses and alloys. The heavy ions (proton and alpha particle) attenuation parameters have been evaluated in energy range between 0.01 and 15 MeV. Regarding the studied glasses, the S5 sample was shown to have the best proton and alpha shielding properties. These results imply that the glass samples under study make good nuclear shielding materials for a range of applications.

Active control of Alfvén eigenmodes by external magnetic perturbations with different spatial spectra

Alfvén eigenmodes have been suppressed and excited in tokamak plasmas by (just) modifying the poloidal spectra of externally applied static magnetic perturbations. This effect is observed experimentally when toroidal spectra of n = 2, n = 4 as well as a mixed spectrum of n = 2 and n = 4 is applied. Under the n = 2 magnetic perturbations, the modes are excited or suppressed by modifying the coil phasing between the upper and the lower set of coils. Regardless of the absolute rotation, an even parity for the n = 4 perturbation is observed to reduce the amplitude of the Alfvénic instabilities, while an odd parity amplifies it. To combine the stabilizing (and destabilizing) effect of n = 2 and n = 4, a mixed spectrum is applied, finding similar reduction (and amplification) trends. However, the impact on the mode amplitude is more subtle, due to the reduced coil current required for a mixed spectrum. The signal level on the fast-ion loss detector is sensitive to the applied poloidal spectrum, which is consistent with Hamiltonian full-orbit modelling of an edge resonant transport layer activated by the 3D perturbative fields. An internal redistribution of the fast-ion population is induced, modifying the phase-space gradients driving the Alfvénic instabilities, and ultimately determining their existence. The calculated edge resonant layers for both n = 2 and n = 4 toroidal spectra are consistent with the observed suppressed and excited phases. Moreover, hybrid kinetic-magnetohydrodynamic (MHD) simulations reveal that this edge resonant transport layer overlaps in phase-space with the population responsible for the fast-ion drive. The results presented here may help to control fast-ion driven Alfvénic instabilities in future burning plasmas with a significant fusion born alpha particle population.

Effects of Alpha Particle Fraction on Kinetic Plasma Turbulence

Solar activities have an extraordinary impact on interplanetary space, enriching the plasma dynamics including turbulent heating of various species. The small fraction of alpha particles is believed to play a significant role in the turbulent dynamics of the solar wind. Here we present fully kinetic particle-in-cell simulations to reveal the influences of the alpha particles in decaying plasma turbulence. Multiple run cases with different controlled variations of proton and alpha density are performed to compare and evaluate the energy conversion processes. It is found that the alpha particles can suppress the energy conversion rate with increasing density. Besides, the alpha particles show more heating intermittency than the proton species. Interestingly, on the other hand, the electrons do not show any change in their dynamics, including overall heating. These two positive charge species have more correlation in temperature anisotropy as their densities are comparable. Our results provide valuable insights on the turbulence with different species compositions to a certain extent, especially with abundant heavy particles.

New target therapies in prostate cancer: from radioligand therapy, to PARP-inhibitors and immunotherapy.

Prostate cancer (PCa) remains a significant global health challenge, particularly in its advanced stages. Despite progress in early detection and treatment, PCa is the second most common cancer diagnosis among men. This review aims to provide an overview of current therapeutic approaches and innovations in PCa management, focusing on the latest advancements and ongoing challenges. We conducted a narrative review of clinical trials and research studies, focusing on PARP inhibitors (PARPis), phosphoinositide 3 kinase-protein kinase B inhibitors, immunotherapy, and radioligand therapies (RLTs). Data was sourced from major clinical trial databases and peer-reviewed journals. Androgen deprivation therapy and androgen-receptor pathway inhibitors remain foundational in managing castration-sensitive and early-stage castration-resistant PCa (CRPC). PARPi's, such as olaparib and rucaparib, have emerged as vital treatments for metastatic CRPC with homologous recombination repair gene mutations, highlighting the importance of personalized medicine. Immune checkpoint inhibitors (ICIs) have shown clinical benefit limited to specific subgroups of PCa, demonstrating significant improvement in efficacy in patients with microsatellite instability/mismatch repair or cyclin-dependent kinase 12 alteration, highlighting the importance of focusing ongoing research on identifying and characterizing these subgroups to maximize the clinical benefits of ICIs. RLTs have shown effectiveness in treating mCRPC. Different alpha emitters (like [225Ac]PSMA) and beta emitters compounds (like [177Lu]PSMA) impact treatment differently due to their energy transfer characteristics. Clinical trials like VISION and TheraP have demonstrated positive outcomes with RLT, particularly [177Lu]PSMA-617, leading to FDA approval. Ongoing trials and future perspectives explore the potential of [225Ac]PSMA, aiming to improve outcomes for patients with mCRPC. The landscape of PCa treatment is evolving, with significant advancements in both established and novel therapies. The combination of hormonal therapies, chemotherapy, PARPis, immunotherapy, and RLTs, guided by genetic and molecular insights, opens new possibilities for personalized treatment.

Assessing radon adsorption capacity in adsorbents using solid state nuclear track detectors (SSNTDs)

Radon, specifically the isotope 222Rn, poses health risks, particularly in concentrated indoor environments. Recent years have underscored the significance of measuring low radon concentrations outdoors, offering crucial insights into radon priority areas and climate-related processes. To achieve the necessary high sensitivity, one approach involves placing radiation detectors in close proximity to efficient radon adsorbers that function as radiators. While activated charcoal has been employed for over a century, recent years have seen the production of highly efficient synthetic adsorbents and activated carbon materials. A vital parameter essential for designing and modeling sensitive radon detectors/monitors is the adsorption capacity of the adsorbent for radon. This study introduces a simple and cost-effective method enabling the determination of the adsorption capacity of numerous prospective adsorbents simultaneously. The method entails placing SSNTDs in close contact with the adsorbent to generate tracks from the alpha particles emitted by adsorbed 222Rn and its progeny. A theoretical model is presented, facilitating the determination of adsorption capacity using SSNTDs with a well-defined response function to alpha particles. Experimental validation involves comparing theoretical estimates with published data from studies on activated charcoals, demonstrating very good agreement. The method's versatility is underscored by its application to activated carbon fabrics, showcasing its potential to optimize detector designs for enhanced sensitivity. This proposed approach holds promise for advancing radon monitoring technology, contributing to improved risk assessment and environmental studies related to radon.

Alpha particle energy-range studies by a layer removal method in polycarbonate detectors for determining unknown ion energies

The aim of this study is to apply a “layer removal method” for alpha energy-range determination in polycarbonate detectors (PC) compared with SRIM software. This method is a precise chemical pre-etching process by which a layer of a certain thickness is removed from an exposed or unexposed PC detector surface before applying electrochemical etching (ECE). A group of 500 μm thick PC detectors was exposed to alpha particles of known fluence (∼1.0 × 104 alphas.cm−2) and ∼0.3–∼5.0 MeV energy range, followed by a pre-etching process at 12 different time intervals in 70% ethylenediamine solution. After the ECE process, alpha track density and diameter were determined. Track density versus removed layer thickness for each alpha energy follows a Bragg type peak after which approaching zero at a known removed layer thickness corresponding to the alpha range. The results also show a linear increase of the mean track diameter as the removed layer thickness increases for each energy. On the other hand, this study confirms a shift in the energy range registration by increasing the thickness of the removed layer. Using this precise method, an unknown energy can be determined by step-by-step thickness removal process until the track density approaches zero. In conclusion, the upper energy of ions emitted in a PFD can be determined. This method is a precise and simple method for ion energy-range determination studies for passive ion spectrometry.

The Alignment of the $${}^{{16}}$$O($${3}^{{-}}$$) Nucleus Formed in Reactions with Alpha Particles

The Alignment of the $${}^{{16}}$$O($${3}^{{-}}$$) Nucleus Formed in Reactions with Alpha Particles

Single event effects evaluation on convolution neural network in Xilinx 28 nm system on chip

Abstract Convolutional neural networks (CNNs) exhibit excellent performance in the areas of image recognition and object detection, which can enhance the intelligence level of spacecraft. However, in aerospace, energetic particles, such as heavy ions, protons, and alpha particles, can induce single event effects (SEEs) that lead CNNs to malfunction and can significantly impact the reliability of a CNN system. In this paper, the MNIST CNN system was constructed based on a 28 nm system-on-chip (SoC), and then an alpha particle irradiation experiment and fault injection were applied to evaluate the SEE of the CNN system. Various types of soft errors in the CNN system have been detected, and the SEE cross sections have been calculated. Furthermore, the mechanisms behind some soft errors have been explained. This research will provide technical support for the design of radiation-resistant artificial intelligence chips.

Cosmology before noon with multiple galaxy populations

Near-future facilities observing the high-redshift universe (2 < z < 5) will have an opportunity to take advantage of “multi-tracer” cosmology by observing multiple tracers of the matter density field: Lyman alpha emitters (LAE), Lyman break galaxies (LBG), and CMB lensing κ. In this work we use Fisher forecasts to investigate the effect of multi-tracers on next-generation facilities. In agreement with previous work, we show that multiple tracers improve constraints primarily from degeneracy breaking, instead of the traditional intuition of sample variance cancellation. Then, we forecast that for both BBN and CMB primary priors, the addition of lensing and LAEs onto a LBG-only sample will gain 25% or more in many parameters, with the largest gains being factor of ∼ 10 improvement for f EDE. We include a preliminary approach towards modelling the impact of radiative transfer (RT) on forecasts involving LAEs by introducing a simplified model at linear theory level. Our results, albeit preliminary, show that while RT influences LAE-only forecasts strongly, its effect on composite multi-tracer forecasts is limited.

Divergence of the energy-losing rate of charged particles in plasmas

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.