Impact Of Alpha Particles Research Articles

Fabrication of a cell irradiation technique by alpha-particles using allyl diglycol carbonate (ADC) detector and micro-capillary tubes.

To study the impact of micro-alpha irradiation collimator with a specific design to irradiate specific normal or up-normal cells using capillary tubes and nuclear track detector type CR-39. The in vitro experimental study was conducted at radiobiology Lab, of the Physics department, Salahaddin University, Erbil, Iraq from February to April 2022. Several alpha irradiation collimators were calibrated using allyl diglycol carbonate to fabricate a suitable blood cell irradiation technique. Time of irradiation and alpha particle energy were calibrated. Healthy blood samples of Albino rats and cancer blood samples were used to assess the applicability of the fabricated cell irradiation technique. The Rats were divided into intervention and control groups. Data was analysed using SPSS software version 28. Of the 15 healthy, male Albino rats having a mean weight of 230±12g each, there were 12(80%) in the intervention group and 3(20%) in the control group. Microcapillary tubes with suitable diameters had high stability for deposition of a sufficient density of alpha particles on the surface of allyl diglycol carbonate and blood samples. The optimum time of irradiation that had a significant (p<0.05) effect was 20 sec corresponding to alpha energy 4.5MeV. Low irradiation time had significant impact of alpha particles on the average percentage of lymphocyte and neutrophil cells.

The impact of fusion-born alpha particles on runaway electron dynamics in ITER disruptions

In the event of a tokamak disruption in a D-T plasma, fusion-born alpha particles take several milliseconds longer to thermalise than the background. As the damping rates drop drastically following the several orders of magnitudes drop of temperature, Toroidal Alfvén Eigenmodes (TAEs) can be driven by alpha particles in the collapsing plasma before the onset of the current quench. We employ kinetic simulations of the alpha particle distribution and show that the TAEs can reach sufficiently strong saturation amplitudes to cause significant core runaway electron (RE) transport in unmitigated ITER disruptions. As the eigenmodes do not extend to the plasma edge, this effect leads to an increase of the RE plateau current. Mitigation via massive material injection however changes the Alfvén frequency and can lead to mode suppression. A combination of the TAE-caused core RE transport with other perturbation sources could lead to a drop of runaway current in unmitigated disruptions.

He2+ impact single ionization cross sections of Cu atom

Semi-classical binary encounter approximation has been used for theoretical calculations of single ionization cross sections of Cu atom at ground state by alpha particle impact in energy range varying from threshold 35 keV/amu to 425 keV/amu. An accurate expression of cross section for energy transfer ΔΕ (σΔΕ) as given by Vriens and quantum mechanical Hartree-Fock velocity distributions for target electrons have been used in the calculation. Major contribution to the total single ionization cross sections of Cu are from 4s and 3d subshells. The ionization cross sections decrease with the increase of impact energy same as experimental data reported. The theoretical and experimental results of single ionization cross sections have same trends against the increase of impact energy. The ratio factor falls within 2, varying from 1.26 to 1.86, for given energy range. Theoretical results are under valid range. About 50% of total theoretical results of single ionization cross sections have ratio factor (R) . Major contribution to total ionization cross section is from 3d and 4s subshells-electrons whose contributions varies from 62 to 71% and 41.7% to 23.8% respectively. The higher value of linear correlation coefficient (=0.9647) and lower value of standard deviation (=0.822) shows that results calculated are close to the experimental data in the intermediate and high energy range. BIBECHANA 19 (2022) 111-118

A 1.2 V, Highly Reliable RHBD 10T SRAM Cell for Aerospace Application

In this article, a highly reliable radiation-hardened-by-design (RHBD) 10T static random access memory (SRAM) cell is proposed. In space, the impact of alpha particles and cosmic radiation flips the node data resulting in loss of data in conventional 6T SRAM. The proposed SRAM has quad-nodes, which stores the data. The architecture is designed with a quad-latch topology and simulated in 65-nm CMOS technology with a supply voltage of 1.2 V. The result shows that the design can tolerate both 0 to 1 and 1 to 0 single event upset errors on any one of its nodes. The read and write access times of the proposed design are 88.78 and 241.77 ps, respectively. The static noise margin for read, write, and hold operations are 379.01, 906.51, and 637.1 mV, respectively. The proposed architecture takes an area of $6.52\,\,\mu \text{m}$ .

He2+ Impact Single Ionization Cross Sections of Fe Atom

Binary encounter approximation has been used for theoretical calculations of alpha particle (He2+) impact single ionization cross sections of iron atom at ground state in the energy range of 35 to 360 keV/amu. The cross sections for energy transfer given by Vriens’ and quantum mechanical Hartree-Fock velocity distributions for target electron have been used in the calculation. The contributions in total single ionization cross sections from 4s and 3d subshells are observed to be higher than from 3p, and the contributions from 4s decreases with increase of impact energy whereas the contribution from 3d increases. The total single ionization cross sections decrease gradually with the increase of impact energy similar to experimental results which implies that our results are in satisfactory agreement with the experimental data in the given energy range.

Measurement of Radon Radiation Concentration in Imported and Local Powdered Milk using Nuclear Track Detector CR - 39

This study aims at measuring radon radiation in 35 different samples of local and imported powdered milk using nuclear track detector CR-39 to record the existence and impact of Alpha particles emitted from radon in the examined samples. Plastic pipes and tubes of the U type were used with the samples in radiating the detector. The study revealed that the highest concentration of radon was (1371.3) Bq.m−1 in the sample M4 (Dielac2-Dubai) and the lowest concentration is in sample M32 (Lamsa- Jordan) with a radon level (151.8) Bq.m−1. The levels of radon that were measured fall within the normal and natural concentration of the radiation that emit from the radionuclide in food and thus do not make any risk to the human life.

Large Field Alpha Irradiation Setup for Radiobiological Experiments.

The use of alpha particles irradiation in clinical practice has gained interest in the past years, for example with the advance of radionuclide therapy. The lack of affordable and easily accessible irradiation systems to study the cell biological impact of alpha particles hampers broad investigation. Here we present a novel alpha particle irradiation set-up for uniform irradiation of cell cultures. By combining a small alpha emitting source and a computer-directed movement stage, we established a new alpha particle irradiation method allowing more advanced biological assays, including large-field local alpha particle irradiation and cell survival assays. In addition, this protocol uses cell culture on glass cover-slips which allows more advanced microscopy, such as super-resolution imaging, for in-depth analysis of the DNA damage caused by alpha particles. This novel irradiation set-up provides the possibility to perform reproducible, uniform and directed alpha particle irradiation to investigate the impact of alpha radiation on the cellular level.

Radiation effects on borosilicate glass irradiated with ions

Vitrification is an extensively accepted method to deal with highly level radioactive waste (HLW). As one of the candidates for immobilizing HLW, the radiation effects on borosilicate glass attract extensive attention. In this work, borosilicate glass samples were irradiated with different ions and radiation effects were studied. The elemental distribution with depth, volume, hardness and modulus variations were measured by ToF SIMS, AFM and nano-indentation, respectively. Trends of changing then saturating in volume, hardness and modulus were illustrated with the increase of dose. The increase of 3.5% in volume, decrease of 35.4% and 18.7% in hardness and modulus, respectively, were measured. Macroscopic properties of borosilicate glass changed remarkably with irradiations of ions. Therefore, one can draw a conclusion that changes in the macroscopic properties (hardness and modulus) of borosilicate glass would happen in condition of alpha decay. Deposition of nuclear stopping in borosilicate glass was an important reason of variations of the macroscopic properties. Both the alpha particle and recoil nucleus contributed the changes in the macroscopic properties of borosilicate glass, none of them was negligible. The radiation effects by impact of alpha particles and recoil nuclear on borosilicate could be simulated by irradiation of single heavy energy ions. These are important to study the radiation effects of alpha decay on vitrification.

Damaging Intermolecular Energy and Proton Transfer Processes in Alpha-Particle-Irradiated Hydrogen-Bonded Systems.

Although the biological hazard of alpha-particle radiation is well-recognized, the molecular mechanisms of biodamage are still far from being understood. Irreparable lesions in biomolecules may not only have mechanical origin but also appear due to various electronic and nuclear relaxation processes of ionized states produced by an alpha-particle impact. Two such processes were identified in the present study by considering an acetylene dimer, a biologically relevant system possessing an intermolecular hydrogen bond. The first process is the already well-established intermolecular Coulombic decay of inner-valence-ionized states. The other is a novel relaxation mechanism of dicationic states involving intermolecular proton transfer. Both processes are very fast and trigger Coulomb explosion of the dimer due to creation of charge-separated states. These processes are general and predicted to occur also in alpha-particle-irradiated nucleobase pairs in DNA molecules.

K-Shell ionization of chlorine and argon due to impact of alpha particles

K-Shell ionization of chlorine and argon due to impact of alpha particles

Study of proton and alpha particle impact double ionization of Fe

Theoretical calculations of H+ and He2+ impact double ionization cross sections for ground state Fe atoms have been performed in the binary encounter approximation(BEA) in the energies region ranging from 80 to 1440 keV/amu for proton impact and from 47 to 360 keV/amu in the case of alpha particle impact. The accurate expression for αδE (cross section for energy transfer ΔE) and Hartree –Fock velocity distributions for the target electrons have been used throughout the calculations. It has been concluded that the calculated results of H+ and He2+ impact double ionization cross sections are in good agreement with the experimental data throughout the given energy range.

Proton and alpha particle impact K-shell ionization of chromium and manganese

K-shell ionization cross sections of Chromium and Manganese have been calculated in the Binary Encounter Approximation and the results have been compared with theoretical cross sections of ECPSSR and the available experimental observations. Present results are found to be comparable to those of ECPSSR with a very less computational effort. Our cross sections show good agreement with experimental values.

Performance of a new atomistic geometrical model of the B-DNA configuration for DNA-radiation interaction simulations

We have recently developed an atomistic model of the B-DNA configuration, up to the 30-nm chromatin fiber. This model is intended to be used in Monte Carlo simulations of the DNA-radiation interaction, specifically in conjunction with the Geant4-DNA extension of the Geant4 Monte Carlo toolkit. In this work, 11449 parallel chromatin fibers have been arranged within a cube mimicking a cell nucleus containing about 6.5×109 base pairs. Each atom in the model is represented by a sphere with the corresponding van der Waals radius. Direct single, double and total DNA strand break yields due to the impact of protons and alpha particles with LET ranging from 4.57 to 207.1 keV/μm have been determined. Also, the corresponding site-hit probabilities have been calculated.

Ionization of water molecules by ion beams. On the relevance of dynamic screening and the influence of the description of the initial state

Single ionization from water molecules by impact of protons, alpha particles and C6 + ions is studied. The post- and prior-versions of the continuum distorted wave-eikonal initial state (CDW-EIS) model within an independent electron approximation are employed to compute double differential cross sections. To avoid the complexity of using numerical molecular continuum states in the cross-section calculations, effective Coulombic continuum wavefunctions are employed. However, this may lead to the appearance of post–prior discrepancies and this fact is examined in detail. Moreover, the influence of the dynamic screening on this behaviour is studied. In addition, the contribution of different molecular orbitals to the angular spectrum is analysed for several ejection electron energies. Finally, the sensitivity of CDW-EIS calculations to the representation of the initial bound molecular orbitals is investigated.

Impact of Alpha Particles on the Electrical Characteristics of TiO$_{2}$ Memristors

Titanium-oxide (TiO2 ) memristors exposed to 1-MeV alpha particles exhibit only minor changes in the electrical response for ion fluencies up to 1014 cm - 2. At higher fluence levels, virgin and off-state devices exhibit measurable increases in current conduction between the two platinum (Pt) electrodes. Analysis, supported by radiation transport and numerical device simulations, suggests that radiation-induced displacement damage in the TiO2 film increases the density of oxygen vacancies, thereby altering both resistivity in the bulk of the transition-metal oxide and the junction characteristics of Pt-TiO2 interface. Nevertheless, the experimental results indicate continued switching functionality of the memristors even after exposure to 1015 cm- 2 alpha particles. The high intrinsic vacancy density in the devices prior to radiation exposure is identified as the primary feature contributing to apparent radiation hardness.

Enhanced production of low energy electrons by alpha particle impact

Radiation damage to living tissue stems not only from primary ionizing particles but to a substantial fraction from the dissociative attachment of secondary electrons with energies below the ionization threshold. We show that the emission yield of those low energy electrons increases dramatically in ion-atom collisions depending on whether or not the target atoms are isolated or embedded in an environment. Only when the atom that has been ionized and excited by the primary particle impact is in immediate proximity of another atom is a fragmentation route known as interatomic Coulombic decay (ICD) enabled. This leads to the emission of a low energy electron. Over the past decade ICD was explored in several experiments following photoionization. Most recent results show its observation even in water clusters. Here we show the quantitative role of ICD for the production of low energy electrons by ion impact, thus approaching a scenario closer to that of radiation damage by alpha particles: We choose ion energies on the maximum of the Bragg peak where energy is most efficiently deposited in tissue. We compare the electron production after colliding He(+) ions on isolated Ne atoms and on Ne dimers (Ne(2)). In the latter case the Ne atom impacted is surrounded by a most simple environment already opening ICD as a deexcitation channel. As a consequence, we find a dramatically enhanced low energy electron yield. The results suggest that ICD may have a significant influence on cell survival after exposure to ionizing radiation.

Electron excitation of hydrogen atom by ions impact in the energy range 20–1000 keV/amu

We have calculated the electron excitation cross sections of hydrogen atom by the impact of protons, alpha particles and He+ ions using the boundary corrected continuum intermediate state approximation in the intermediate and high energies. The calculated results are compared with other theoretical and experimental results. The angular influence of excitation to the H atom at the intermediate energy is also discussed. The distortion effects due to the projectile charges in reactions of electron excitation to bound states of the target H atom are shown in the intermediate and high collision energy.

New Geant4 cross section models for PIXE simulation

We have implemented in the Geant4 simulation toolkit a set of new ionisation cross sections for the simulation of particle induced X-ray emission (PIXE), based upon theoretical and semi-empirical models. The set provides a model based on the so-called ECPSSR theory for the computation of K-shell ionisation cross sections for proton and alpha particle impact. A second model is based upon semi-empirical expressions proposed by Orlic for the calculation of L i -subshells ionisation cross sections for proton impact. Our developments are compared to ionisation cross sections already existing in the Geant4 toolkit and to experimental data.

Ionization of sodium by the impact of alpha particle

A one channel distorted wave approximation has been used to calculate the ionization cross section for the 3s electron of Na atom by alpha particle impact. For a consistency check we have also run the standard CDW-EIS code of McSherry et al. [Comput. Phys. Commun. 155, 144 (2003)] and found reasonable agreement in the high energy region among the present results, the CDW-EIS results and the classical trajectory Monte Carlo (CTMC) calculations. It is also found that the present results tend to agree qualitatively with the low energy measurement of Knoop et al. [J. Phys. B 38, 1987 (2005)] at as low as 10 keV amu-1, although the present theoretical approach is expected to be suitable in the high energy area. This qualitative agreement in the low energy region is attributed to the partially correlated ground state wave function used in the present calculation.

Theoretical investigation of fragmentation effects in the energy deposition of swift ions in formaldehyde

We report the beginnings of a study of the impact of swift alpha particles on the smallest of the protobiological molecules: formaldehyde. We report the kinetic energy release for C, O, and H ions for projectile energies of 1.5, 3.0 and 5.0 keV.