Charged Particle Irradiation Research Articles

Trajectories and radiation of charged particles in the pulsar magnetosphere

ABSTRACT Trajectories and radiation of the accelerating electrons are studied in the pulsar magnetosphere approximated as the electromagnetic field of the Deutsch’s solutions. Because the electrons are accelerated rapidly to ultra-relativistic velocity near the neutron star surface, the electron velocity vector (and then its trajectory) is derived from the balance between Lorentz force and radiation reaction force, which makes the pitch angle between electron trajectories and magnetic field lines non-zero in most part of the magnetosphere. In such a case, the spectral energy distributions (SEDs) of synchro-curvature radiation for the accelerating electrons with a mono-energetic form are calculated. Our results indicate that: (i) the pitch angle is the function of electron position (r, θ, ϕ) in the open field line regions, and increases with increasing r and θ as well as increasing the inclination angle; (ii) the radius of curvature becomes large along the particle trajectory, and (iii) the SED appears a double peak structure depending on the emission position, where the synchrotron radiation plays an important role in X-ray band and curvature radiation mainly works in GeV band, which is only determined by parameters α and ζ.

High turnover and rescue effect of XRCC1 in response to heavy charged particle radiation

The DNA damage response is a highly orchestrated process. The involvement of the DNA damage response factors in DNA damage response depends on their biochemical reactions with each other and with chromatin. Using online live-cell imaging combined with heavy ion microbeam irradiation, we studied the response of the scaffold protein X-ray repair cross-complementary protein 1 (XRCC1) at the localized DNA damage in charged particle irradiated HT1080 cells expressing XRCC1-tagged RFP. The results showed that XRCC1 was recruited to the DNA damage with ultrafast kinetics in a poly ADP-ribose polymerase-dependent manner. The consecutive reaction model well explained the response of XRCC1 at ion hits, and we found that the XRCC1 recruitment was faster and dissociation was slower in the G2 phase than those in the G1 phase. The fractionated irradiation of the same cells resulted in accelerated dissociation at the previous damage sites, and the dissociated XRCC1 immediately recycled with a higher recruitment efficiency. Our data revealed XRCC1’s new rescue mechanism and its high turnover in DNA damage response, which benefits our understanding of the biochemical mechanism in DNA damage response.

An SRAM SEU Cross Section Curve Physics Model

Static random access memories (SRAMs) are prone to a single-event upset (SEU), also known as soft errors, due to transient noise caused by a single strike of radiation. Beam testing has been extensively used to measure the SEU cross section of SRAMs as a function of the linear energy transfer (LET) of charged particle radiation. The evolution of the cross section as a function of LET is called the cross section curve, which plays a vital role in upset rate analysis for hardness assurance. Various analytical models have been developed to describe SRAM SEU cross-section curves, and they have proven to be useful in reducing the cost of beam testing as well as revealing the physics behind test results. However, they involve arbitrary parameters, which make it challenging to predict cross-section curves without any beam results. Moreover, the current method of analyzing cross-section curves or the LET dependence of cross sections relies on a model different from that is used in the analysis of power-supply-voltage dependence, which is becoming increasingly important because of the demand for low-power operation. To overcome these problems, this paper proposes a unified equation that describes both LET and the power-supply-voltage dependence of SRAM SEU cross sections. It comprises only parameters that are physically clear and familiar to SEU researchers. As well as giving possible constraints, comparisons with data from the literature suggest it can be applied to SRAMs fabricated in bulk and silicon-on-insulator (SOI) processes across generations from the early 1000-nm-scale to the current 10-nm-scale technology nodes.

Personalized 3D-printed anthropomorphic whole-body phantom irradiated by protons, photons, and neutrons

The objective of this study was to confirm the feasibility of three-dimensionally-printed (3D-printed), personalized whole-body anthropomorphic phantoms for radiation dose measurements in a variety of charged and uncharged particle radiation fields. We 3D-printed a personalized whole-body phantom of an adult female with a height of 154.8 cm, mass of 90.7 kg, and body mass index of 37.8 kg/m2. The phantom comprised of a hollow plastic shell filled with water and included a watertight access conduit for positioning dosimeters. It is compatible with a wide variety of radiation dosimeters, including ionization chambers that are suitable for uncharged and charged particles. Its mass was 6.8 kg empty and 98 kg when filled with water. Watertightness and mechanical robustness were confirmed after multiple experiments and transportations between institutions. The phantom was irradiated to the cranium with therapeutic beams of 170-MeV protons, 6-MV photons, and fast neutrons. Radiation absorbed dose was measured from the cranium to the pelvis along the longitudinal central axis of the phantom. The dose measurements were made using established dosimetry protocols and well-characterized instruments. For the therapeutic environments considered in this study, stray radiation from intracranial treatment beams was the lowest for proton therapy, intermediate for photon therapy, and highest for neutron therapy. An illustrative example set of measurements at the location of the thyroid for a square field of 5.3 cm per side resulted in 0.09, 0.59, and 1.93 cGy/Gy from proton, photon, and neutron beams, respectively. In this study, we found that 3D-printed personalized phantoms are feasible, inherently reproducible, and well-suited for therapeutic radiation measurements. The measurement methodologies we developed enabled the direct comparison of radiation exposures from neutron, proton, and photon beam irradiations.

Спектрально-угловые характеристики излучения заряженной частицы в поле Редмонда

Based on the solution of the equation of motion of a charge in an electromagnetic field, the classical theory of radiation of a relativistic charged particle linearly accelerated by a high-intensity laser pulse in the presence of a static component of the magnetic field is constructed. Solutions obtained by Kopytov G.F. and Pogorelov A.V., were used to study the spectral-angular characteristics of the radiation of a charged particle in a combination of the field of a plane monochromatic electromagnetic wave and a constant magnetic field, the so-called Redmond field. According to the calculated formulas for the radiation intensity of particles in the Redmond field, graphs of the dependence on the magnitude of the magnetic field, phase and phase-angular distributions are plotted. The Fourier transform of the intensity of the electric field of the radiation and the spectral density of the radiation of the particle in the case of linear polarization of the wave is obtained.

Spectral-angular characteristics of the radiation of a charged particle in the Redmond field

Based on the solution of the equation of motion of a charge in an electromagnetic field, the classical theory of radiation of a relativistic charged particle linearly accelerated by a high-intensity laser pulse in the presence of a static component of the magnetic field is constructed. Solutions obtained by Kopytov G.F. and Pogorelov A.V., were used to study the spectral-angular characteristics of the radiation of a charged particle in a combination of the field of a plane monochromatic electromagnetic wave and a constant magnetic field, the so-called Redmond field. According to the calculated formulas for the radiation intensity of particles in the Redmond field, graphs of the dependence on the magnitude of the magnetic field, phase and phase-angular distributions are plotted. The Fourier transform of the intensity of the electric field of the radiation and the spectral density of the radiation of the particle in the case of linear polarization of the wave is obtained. Keywords: Redmond field, spectral-angular characteristics, charged particle, Lawson-Woodward theorem, superpower laser radiation.

Synchrotron FTIR Microspectroscopy Investigations on Biochemical Changes Occurring in Human Cells Exposed to Proton Beams

Fourier transform infrared microspectroscopy using a synchrotron radiation source (SR-μFTIR) has great potential in the study of the ionizing radiation effects of human cells by analyzing the biochemical changes occurring in cell components. SR-μFTIR spectroscopy has been usefully employed in recent years in some seminal work devoted to shedding light on processes occurring in cells treated by hadron therapy, that is, radiotherapy with charged heavy particles (mainly protons and carbon ions), which is gaining popularity as a cancer treatment modality. These studies are particularly useful for increasing the effectiveness of radiotherapy cancer treatments with charged particles that can offer significant progress in the treatment of deep-seated and/or radioresistant tumors. In this paper, we present a concise revision of these studies together with the basic principles of μFTIR spectroscopy and a brief presentation of the main characteristics of infrared SR sources. From the analysis of the literature regarding the SR-μFTIR spectroscopy investigation on human cells exposed to proton beams, it is clearly shown that changes in DNA, protein, and lipid cell components are evident. In addition, this review points out that the potential offered by SR-μFTIR in investigating the effects induced by charged particle irradiation have not been completely explored. This is a crucial point for the continued improvement of hadron therapy strategies.

Characterization and qualification of neutron radiation effects – Summary of Japan-USA Joint Projects for 40 years –

The Joint Projects under the Japan-USA Fusion Cooperation Program started in 1981 and has continued for more than 40 years. In the Joint Projects, although a wide range of fusion materials and engineering issues were covered, neutron radiation effects on fusion reactor materials have always been the major research emphases, and the neutron irradiation facilities in the US were jointly used by Japanese and US researchers. Japanese test facilities including neutron and charged particle irradiation facilities were complementarily used.The initial focus of the Joint Projects was on fundamental fusion neutron radiation effects and irradiation correlation. Systematic comparison of fission and fusion radiation effects in comparable damage levels and the effects of transmutation-induced helium were investigated. The collaboration was then focused on the effect of dynamic irradiation effects in variable conditions. In addition to the relatively fundamental studies, the Joint Projects contributed largely to development of candidate materials such as RAFM steels, vanadium alloys, SiC/SiC composites, and tungsten alloys, through a mechanism-oriented approach. The Joint Projects also covered issues specific to materials application to fusion blankets and plasma-facing components, including neutron radiation effects such as tritium retention and permeation of neutron-irradiated plasma-facing materials. Various irradiation technologies were developed and applied to the irradiation experiments, including those for in-situ testing.Considering that high energy neutron sources, such as A-FNS and IFMIF-DONES, now have high viability, the research supporting the neutron source programs is essential. The knowledge obtained through the Joint Projects is valuable and should be advanced for this purpose. To this end, it is of urgent necessity to launch an international scientific program accumulating knowledge of fusion neutron radiation effects, including their fundamental aspects.

Hawking-like radiation of charged particles via tunneling across the lightcylinder of a rotating magnetosphere

In rotating magnetospheres planted on compact objects, there usually exist lightcylinders (LC), beyond which the rotation speed of the magnetic field lines exceeds the speed of light. The LC is a close analog to the horizon in gravity, and is a casual boundary for charged particles that are restricted to move along the magnetic field lines. In this work, it is proposed that there should be Hawking-like radiation of charged particles from the LC of a rotating magnetosphere from the point of view of tunneling by using the field sheet metric.

RIPTIDE: a novel recoil-proton track imaging detector for fast neutrons

Neutron detectors are an essential tool for the development of many research fields, as nuclear, particle and astroparticle physics as well as radiotherapy and radiation safety. Since neutrons cannot directly ionize, their detection is only possible via nuclear reactions. Consequently, neutron-based experimental techniques are related to the detection of charged particle or electromagnetic radiation originating from neutron-induced reactions. The study of fast neutrons is often based on the neutron-proton elastic scattering reaction. In this case, the ionization induced by the recoil protons in a hydrogenous material constitutes the basic information for the design and development of neutron detectors. Although experimental techniques have continuously improved and refined, so far, proton-recoil track imaging is still weak in laboratory rate environments because of the extremely small detection efficiency. To address this deficiency, we propose a novel recoil-proton track imaging system in which the light deriving from a fast scintillation signal is used to perform a complete reconstruction in space and time of the event. In particular, we report the idea of RIPTIDE (RecoIl Proton Track Imaging DEtector): an innovative system which combines a plastic scintillator coupled to imaging devices, based on CMOS technology, or micro channel plate sensors. The proposed apparatus aims at providing neutron spectrometry capability by stereoscopically imaging the recoil-protons tracks, correlating the spatial information with the time information. RIPTIDE intrinsically enable the online analysis of the ionization track, thus retrieving the neutron direction and energy, without spoiling the overall efficiency of the detection system. Finally, the spatial and topological event reconstruction enables particle discrimination — a crucial requirement for neutron detection — by deducing the specific energy loss along the track.

Improvement of Performance Characteristics for LiI:Ag Single‐Crystal Scintillators by Defect Structure Tailoring Using Sr Codopant

Lithium iodides are very efficient single‐crystal scintillators for thermal neutron detection. Doping with silver, as activator ions, has shown to improve its limitation of discriminating gamma background by introducing pulse shape discrimination ability. To improve the scintillation performance, single crystals of LiI:Ag, codoped with different concentration of Sr ions, are grown and characterized in details. A systematic investigation of radioluminescence, thermoluminescence, and scintillation properties along with the decay kinetics provides better understanding about the role of defect structure in scintillation mechanism. The extra charge, provided by Sr2+ ions, is found to alter the defect structure with relative reduction of the contribution from the deeper trap centers in comparison with the shallow traps. Consequently, it leads to a significant improvement of light yield quenching under higher excitation density of charged particle irradiation. The 0.1% Sr codoped crystals provide a better discrimination ability of neutron and gamma radiations for simultaneous detection.

Novel Cu/Zn Reinforced Polymer Composites: Experimental Characterization for Radiation Protection Efficiency (RPE) and Shielding Properties for Alpha, Proton, Neutron, and Gamma Radiations.

In this study, brass (Cu/Zn) reinforced polymer composites with different proportions of brass powders were fabricated. Different types of nuclear shielding parameters such as mass and linear attenuation coefficients, radiation protection efficiency, half and tenth value layers, and effective atomic number values were determined experimentally and theoretically in the energy range of 0.060–1.408 MeV in terms of gamma-ray shielding capabilities of fabricated polymer composites. A high Purity Germanium detector (HPGe) in conjunction with a Multi-Channel Analyzer (MCA) and twenty-two characteristic gamma-ray energies have been used in the experimental phase. In addition, the exposure and energy absorption buildup factors of reinforced Cu/Zn composites were calculated, and relative dose distribution values were computed to verify them. Proton mass stopping power (ΨP), proton projected range (ΦP), alpha mass stopping power (ΨA), and alpha projected range (ΦA) parameters, which indicate the interactions of the produced composites with charged particle radiation, were investigated. Fast neutron removal cross-section (ΣR) results were determined to give an idea in terms of neutron shielding. According to the obtained results, it is reported that the CuZn20 coded sample’s ability to attenuate gamma-ray and charged particle radiation is more efficient than that of other prepared composites. A CuZn05 coded sample was found to be more suitable for neutron shielding capability.

Gamma, Fast Neutron, Proton, and Alpha Shielding Properties of Borate Glasses: A Closer Look on Lead (II) Oxide and Bismuth (III) Oxide Reinforcement

The purpose of this research was to investigate the shielding characteristics of high-amount heavy metal oxide and Eu3+-activated borate glasses based on 10La2O3–50HMO–(40–x) B2O3–xEu2O3 (x = 0, 0.5, 1, 2, and HMO = PbO, Bi2O3). Critical gamma radiation attenuation characteristics, particularly mass attenuation coefficients of investigated heavy metal oxide glass samples, were determined using Monte Carlo simulations and the Phy-x/PSD software. Following that, we looked at the half-value layer, mean free path, effective atomic number, and build-up factors across a broad energy range (0.015–15 MeV). According to the study’s results, the addition of Eu2O3 enhanced the mass attenuation coefficient and effective atomic number, while reducing the half-value layer, mean free path, and accumulation factors. In terms of gamma radiation attenuation, the LBi50BEu glass system surpassed the LPb50BEu glass system in terms of overall shielding properties against nuclear radiation. Additionally, the heavy metal oxide glass’ efficacy as a neutron shield was determined using fast neutron removal cross-sections (ΣR). LBi50BEu2 glass was shown to be more effective in preventing the penetration of charged particle radiation.

Irradiation behavior and recovery effect of ferroelectric properties of PZT thin films* *Project supported by the National Natural Science Foundation of China (Grant No. 51802056), the Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, and the Key Laboratory of Micro-systems and Micro-structures Manufacturing (Harbin Institute of Technology), Ministry of Education, China.

Lead zirconate titanate piezoelectric ceramics have important applications in space and aerospace technology, but the effect and physical mechanism of charged particle radiation on their performance yet to be clarified. In this study, we characterized PbZr0.52Ti0.48O3 (PZT) thin films, and changes in the ferroelectric properties of the films before and after electron and proton irradiation were investigated. The natural and heat treatment recoverability of the ferroelectric properties were studied, and the damages and mechanisms of different types of radiation in PZT films were also investigated. The results show that, in addition to ionization damages, electron irradiation causes certain structural damage on the PZT film, and the large structural damage caused by proton irradiation reduces drastically the ferroelectricity of the PZT film.

O-GlcNAcylation Affects the Pathway Choice of DNA Double-Strand Break Repair.

Exposing cells to DNA damaging agents, such as ionizing radiation (IR) or cytotoxic chemicals, can cause DNA double-strand breaks (DSBs), which are crucial to repair to maintain genetic integrity. O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) is a post-translational modification (PTM), which has been reported to be involved in the DNA damage response (DDR) and chromatin remodeling. Here, we investigated the impact of O-GlcNAcylation on the DDR, DSB repair and chromatin status in more detail. We also applied charged particle irradiation to analyze differences of O-GlcNAcylation and its impact on DSB repair in respect of spatial dose deposition and radiation quality. Various techniques were used, such as the γH2AX foci assay, live cell microscopy and Fluorescence Lifetime Microscopy (FLIM) to detect DSB rejoining, protein accumulation and chromatin states after treating the cells with O-GlcNAc transferase (OGT) or O-GlcNAcase (OGA) inhibitors. We confirmed that O-GlcNAcylation of MDC1 is increased upon irradiation and identified additional repair factors related to Homologous Recombination (HR), CtIP and BRCA1, which were increasingly O-GlcNAcyated upon irradiation. This is consistent with our findings that the function of HR is affected by OGT inhibition. Besides, we found that OGT and OGA activity modulate chromatin compaction states, providing a potential additional level of DNA-repair regulation.

Electromagnetic microwave generation by acoustic vibrations gives rise to nanoradiophotonics

The development of new methods for generating pulsed electromagnetic microwave radiation is currently an actively developing area of research. Schemes for microwave radiation generation with optical pumping are of great interest. In this paper we propose and experimentally demonstrate principally new method for photonic generation of microwave electromagnetic radiation. This method is based on the use of radiation of charged submicron particles oscillating at their own acoustic frequency. Laser radiation of the optical range implements an effective buildup of acoustic vibrations of submicron particles forming the system under study, according to the Raman mechanism.

Short-term metabolic disruptions in urine of mouse models following exposure to low doses of oxygen ion radiation

Molecular alterations as a result of exposure to low doses of high linear energy transfer (LET) radiation can have deleterious short- and long-term consequences on crew members embarking on long distance space missions. Oxygen ions (16O) are among the high LET charged particles that make up the radiation environment inside a vehicle in deep space. We used mass spectrometry-based metabolomics to characterize urinary metabolic profiles of male C57BL/6J mice exposed to a single dose of 0.1, 0.25 and 1.0 Gy of 16O (600 MeV/n) at 10 and 30 days post-exposure to delineate radiation-induced metabolic alterations. We recognized a significant down regulation of several classes of metabolites including cresols and tryptophan metabolites, ketoacids and their derivatives upon exposure to 0.1 and 0.25 Gy after 10 days. While some of these changes reverted to near normal by 30 days, some metabolites including p-Cresol sulfate, oxalosuccinic acid, and indoxylsulfate remained dysregulated at 30 days, suggesting long term prognosis on metabolism. Pathway analysis revealed a long-term dysregulation in multiple pathways including tryptophan and porphyrin metabolism. These results suggest that low doses of high-LET charged particle irradiation may have long-term implications on metabolic imbalance.

Consequences of space radiation on the brain and cardiovascular system

Staying longer in outer space will inevitably increase the health risks of astronauts due to the exposures to galactic cosmic rays and solar particle events. Exposure may pose a significant hazard to space flight crews not only during the mission but also later, when slow-developing adverse effects could finally become apparent. The body of literature examining ground-based outcomes in response to high-energy charged-particle radiation suggests differential effects in response to different particles and energies. Numerous animal and cellular models have repeatedly demonstrated the negative effects of high-energy charged-particle on the brain and cognitive function. However, research on the role of space radiation in potentiating cardiovascular dysfunction is still in its early stages. This review summarizes the available data from studies using ground-based animal models to evaluate the response of the brain and heart to the high-energy charged particles of GCR and SPE, addresses potential sex differences in these effects, and aims to highlight gaps in the current literature for future study.

Effects of 16O charged-particle irradiation on cognition, hippocampal morphology and mutagenesis in female mice

The effects of radiation in space on human cognition are a growing concern for NASA scientists and astronauts as the possibility for long-duration missions to Mars becomes more tangible. Oxygen (16O) radiation is of utmost interest considering that astronauts will interact with this radiation frequently. 16O radiation is a class of galactic cosmic ray (GCR) radiation and also present within spacecrafts. Whole-body exposure to high linear energy transfer (LET) radiation has been shown to affect hippocampal-dependent cognition. To assess the effects of high-LET radiation, we gave 6-month-old female C57BL/6 mice whole-body exposure to 16O at 0.25 or 0.1 Gy at NASA’s Space Radiation Laboratory. Three months following irradiation, animals were tested for cognitive performance using the Y-maze and Novel Object Recognition paradigms. Our behavioral data shows that 16O radiation significantly impairs object memory but not spatial memory. Also, dendritic morphology characterized by the Sholl analysis showed that 16O radiation significantly decreased dendritic branch points, ends, length, and complexity in 0.1 Gy and 0.25 Gy dosages. Finally, we found no significant effect of radiation on single nucleotide polymorphisms in hippocampal genes related to oxidative stress, inflammation, and immediate early genes. Our data suggest exposure to heavy ion 16O radiation modulates hippocampal neurons and induces behavioral deficits at a time point of three months after exposure in female mice.

Characterisation of hydrogen ion implantation damage in quartz, lithium niobate and tellurium dioxide by Raman spectroscopy

We report observations of the Raman spectra of 10 keV hydrogen ion-implanted crystalline quartz, lithium niobate and tellurium dioxide over a wide range of ion fluences (– protons/cm). We observe the emergence and growth of a new fluorescence feature in the Raman spectra (peaked at 1535 cm) as a function of fluence in all three materials. When measured, the position and shape of this feature is nearly identical in each material. However, the appearance of this feature in tellurium dioxide has a slightly varied behaviour. Based on our observations, we suggest that this signal is due to the 557.7 nm photoluminescence of interstitial atomic O formed radiolytically. While interstitial molecular O2 has previously been observed in irradiated quartz, the presence of this atomic oxygen signature in proton-irradiated lithium niobate and tellurium dioxide has not been previously reported. Our results are important for the use of these materials, and other crystalline oxides, in charged particle (proton) radiation rich environments, such as those encountered by spaceborne instrumentation.