Γ-ray Irradiation Research Articles

γ-Ray Irradiation Significantly Enhances Capacitive Energy Storage Performance of Polymer Dielectric Films.

Polymer dielectric capacitors are fundamental in advanced electronics and power grids but suffer from low energy density, hindering miniaturization of compact electrical systems. It is shown that high-energy and strong penetrating γ-irradiation significantly enhances capacitive energy storage performance of polymer dielectrics. γ-irradiated biaxially oriented polypropylene (BOPP) films exhibit an extraordinarily high energy density of 10.4 J cm-3 at 968 MV m-1 with an efficiency of 97.3%. In particular, an energy density of 4.06 J cm-3 with an ultrahigh efficiency of 98% is reliably maintained through 20000 charge-discharge cycles under 600 MV m-1. At 125°C, the γ-irradiated BOPP film still delivers a high discharged energy density of 5.88 J cm-3 with an efficiency of 90% at 770 MV m-1. Substantial improvements are also achieved for γ-irradiated cycloolefin copolymers at a high temperature of 150°C, verifying the strategy generalizability. Experimental and theoretical analyses reveal that the excellent performance should be related to the γ-irradiation induced polar functional groups with high electron affinity in the molecular chain, which offer deep energy traps to impede charge transport. This work provides a simple and generally applicable strategy for developing high-performance polymer dielectrics.

Dual-vacancies modulation of 1T/2H heterostructured MoS2-CdS nanoflowers via radiolytic radical chemistry for efficient photocatalytic H2 evolution

Precise defect engineering of photocatalysts is highly demanding but remains a challenge. Here, we developed a facile and controllable γ-ray radiation strategy to assemble dual-vacancies confined MoS2-CdS-γ nanocomposite photocatalyst. We showed the solvated electron induced homogeneous growth of defects-rich CdS nanoparticles, while the symbiotic •OH radicals etched flower-like 1T/2H MoS2 substrate surfaces. The optimal MoS2-CdS-γ exhibited a H2 evolution rate of up to 37.80 mmol/h/g under visible light irradiation, which was 36.7 times higher than that of bare CdS-γ, and far superior to those synthesized by hydrothermal method. The microscopic characterizations and theoretical calculations revealed the formation of such unprecedented dual-sulfur-vacancies ensured the tight interfacial contact for fast charge separation. Besides, the existence of 1T-MoS2 phase further improved the conductivity and strengthened the adsorption interaction with H+ intermediate. Therefore, the radiolytic radical chemistry offered a facile, ambient and effective synthetic strategy to improve the catalytic performances of photocatalytic materials.

Progress in Research on the Preparation of Graphene-Based Aerogels Using γ-ray Irradiation Technology.

Graphene aerogels (GAs) are of significant interest in the scientific community due to their unique attributes, including a three-dimensional porous structure, exceptional specific surface area, and remarkable chemical stability. Researchers have made notable breakthroughs in aerogel preparation, focusing on aspects like porous structures and chemical stability. This review explores product morphologies and properties developed between 2011 and 2023, particularly examining applications of graphene aerogels with amine or alcohol radical scavengers. It offers a roadmap for researchers, suggesting possibilities for radiation-based preparation and indicating broader applications. These findings contribute to a deeper understanding of aerogels and expand the potential applications of graphene aerogels across various fields.

Investigation of high resistivity [formula omitted]-type FZ silicon diodes after 60Co [formula omitted]-irradiation

In this work, the effects of 60Co γ-ray irradiation on high resistivity p-type diodes have been investigated. The diodes were exposed to dose values of 0.1, 0.2, 1, and 2MGy. Both macroscopic (I–V, C–V) and microscopic investigations, by means of Thermally Stimulated Current (TSC) and Deep Level Transient Spectroscopy (DLTS) techniques, were conducted to characterize the radiation-induced changes. The investigated diodes were manufactured on high resistivity p-type Float Zone (FZ) silicon and were further classified into two types based on the isolation technique between the pad and guard ring: p-stop and p-spray. After irradiation, the macroscopic results of current–voltage and capacitance–voltage measurements were obtained and compared with existing literature data. Additionally, the microscopic measurements focused on the development of the concentration of different radiation-induced defects, including the Boron interstitial-Oxygen interstitial (BiOi) complex, the Carbon interstitial-Oxygen interstitial (CiOi) defect, the H40K, and the so-called IP∗.To investigate the thermal stability of induced defects in the bulk, isochronal annealing studies were performed in the temperature range of 100°C to 300°C. These annealing processes were carried out on diodes irradiated with doses of 1 and 2MGy. Furthermore, in order to investigate the unexpected results observed in the C–V measurements after irradiation with high dose values, the surface conductance between the pad and guard ring was measured as a function of both dose and annealing temperature.

Effective removal of heavy metals from aqueous solution using CS/OMMT nanocomposite synthesized by gamma irradiation

The current investigation involved the fabrication of nanocomposites CS/OMMT through polymerization initiated by γ-rays irradiation. The product was characterized using FTIR and SEM techniques. The current analysis aimed to determine the adsorption performance of lead (II) ions onto nanocomposites that were synthesized, using a batch adsorption technique in an aqueous medium. The investigation analyzed the influence of different issues on the adsorption capability of the nanocomposite. Further, the lead (II) concentration, medium pH, contact time & adsorbent use were taken into account. Adsorption process order was determined with the help of kinetics. Kinetics data of pseudo 1st and 2nd order models were analyzed. There was a strong correlation between the data and the second-order kinetic model. Based on our research, we conclude that the nanocomposite showed good agreement with the Langmuir model of Pb(II) ions. The nanocomposite underwent a desorption procedure utilizing solutions of CaCl2, NaCl and 0.01 M HNO3 to attain complete elimination of Pb(II) ions. This process are revealed that CS/OMMT demonstrated remarkable efficacy as an absorbent for heavy metal ions, suggesting its potential as a viable method for purifying heavy metal-contaminated water.

Effect of Proton Irradiation on Complementary Metal Oxide Semiconductor (CMOS) Single-Photon Avalanche Diodes

The effects of proton irradiation on CMOS Single-Photon Avalanche Diodes (SPADs) are investigated in this article. The I–V characteristics, dark count rate (DCR), and photon detection probability (PDP) of the CMOS SPADs were measured under 30 MeV and 52 MeV proton irradiations. Two types of SPAD, with and without shallow trench isolation (STI), were designed. According to the experimental results, the leakage current, breakdown voltage, and PDP did not change after irradiation at a DDD of 2.82 × 108 MeV/g, but the DCR increased significantly at five different higher voltages. The DCR increased by 506 cps at an excess voltage of 2 V and 10,846 cps at 10 V after 30 MeV proton irradiation. A γ irradiation was conducted with a TID of 10 krad (Si). The DCR after the γ irradiation increased from 256 cps to 336 cps at an excess voltage of 10 V. The comparison of the DCR after proton and γ-ray irradiation with two structures of SPAD indicates that the major increase in the DCR was due to the depletion region defects caused by proton displacement damage rather than the Si-SiO2 interface trap generated by ionization.

The multi-scale structure changes of γ-ray irradiated potato starch to mitigate pasting/digestion properties

The comprehensive understanding of multi-scale structure of starch and how the structure regulates the pasting/digestion properties remain unclear. This work investigated the effects of γ-ray irradiation with different doses on multi-scale structure and pasting/digestion properties of potato starch. Results indicated that γ-ray at lower doses (<20 kGy) had little effect on micromorphology of starch, increased mainly the amylose content and the thickness of amorphous region while decreased crystallinity, double helix content and lamellar ordering. With the increase of dose, the internal structure of large granules was destroyed, resulting in the depolymerization of starch to form more short-chains and to reduce molecular weight. Meanwhile, amylose content decreased due to the depolymerization of amylose. The enhanced double helix content, crystallinity, lamellar ordering and structural compactness manifested the formation of the thicker and denser starch structure. These structure changes resulted in the decreased viscosity, the increased stability and anti- digestibility of paste.

Effect of controlled solvent evaporation on the electroactive phase content of P (VDF-HFP) films

Poly (vinylidene fluoride)-based dielectric materials have attracted much attention in the field of high power density electric energy storage due to their ferroelectric properties, high dielectric breakdown strength and superior processability. However, it is a key challenge how to obtaining high content electroactive phases with ferroelectric and piezoelectric properties in PVDF. Up till now, researchers have prepared PVDF films with high content of electroactive phase via irradiation with high-energy electron-beam or γ-ray radiations and pressing-and-folding process. In this paper, P(VDF-HFP) films were prepared by controlled solvent evaporation method at different ambient temperature. The results showed that the morphologiy of the film showed insignificant changes with the increase of ambient temperature. Total contents of β and γ phases were nearly 100 % in the PVDF films prepared at ambient temperature below 110 °C. The microcrystals in P(VDF-HFP) was more and more perfect with the increase of the ambient temperature under the condition of controlled solvent evaporation. The films prepared at 70 °C showed a dielectric constant of 12.76 under the test condition of 100 Hz with the remnant polarization of 0.54 μC/cm2. All of these results demonstrated that the formation of the electroactive phase of P(VDF-HFP) thin films was related to the evaporation process and evaporate rate of the solvent.

Transcriptome analysis of cultured human vascular endothelial cells after γ-ray irradiation and correlation analysis with ATP, ADP, and adenosine as secondary soluble factors.

Vascular endothelial cells serve as barriers between blood components and subendothelial tissue and regulate the blood coagulation-fibrinolytic system. Ionizing radiation is a common physical stimulant that induces a bystander effect whereby irradiated cells influence neighboring cells through signalings, including purinergic receptor signaling, activated by adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and adenosine as secondary soluble factors. Human vascular endothelial EA.hy926 cells were cultured and irradiated with γ-rays or treated with ATP, ADP, or adenosine under non-toxic conditions. RNA-seq, gene ontology, and hierarchical clustering analyses were performed. The transcriptome analysis of differentially expressed genes in vascular endothelial cells after γ-ray irradiations suggests that the change of gene expression by γ-irradiation is mediated by ATP and ADP. In addition, the expression and activity of the proteins related to blood coagulation and fibrinolysis systems appear to be secondarily regulated by ATP and ADP in vascular endothelial cells after exposure to γ-irradiation. Although it is unclear whether the changes of the gene expression related to blood coagulation and fibrinolysis systems by γ-irradiation affected the increased hemorrhagic tendency through the exposure to γ-irradiation or the negative feedback to the activated blood coagulation system, the present data indicate that toxicity associated with γ-irradiation involves the dysfunction of vascular endothelial cells related to the blood coagulation-fibrinolytic system, which is mediated by the signalings, including purinergic receptor signaling, activated by ATP and ADP.

Involvement of Cannabinoid Receptors and Adenosine A2B Receptor in Enhanced Migration of Lung Cancer A549 Cells Induced by γ-Ray Irradiation.

Residual cancer cells after radiation therapy may acquire malignant phenotypes such as enhanced motility and migration ability, and therefore it is important to identify targets for preventing radiation-induced malignancy in order to increase the effectiveness of radiotherapy. G-Protein-coupled receptors (GPCRs) such as adenosine A2B receptor and cannabinoid receptors (CB1, CB2, and GPR55) may be involved, as they are known to have roles in proliferation, invasion, migration and tumor growth. In this study, we investigated the involvement of A2B and cannabinoid receptors in γ-radiation-induced enhancement of cell migration and actin remodeling, as well as the involvement of cannabinoid receptors in cell migration enhancement via activation of A2B receptor in human lung cancer A549 cells. Antagonists or knockdown of A2B, CB1, CB2, or GPR55 receptor suppressed γ-radiation-induced cell migration and actin remodeling. Furthermore, BAY60-6583 (an A2B receptor-specific agonist) enhanced cell migration and actin remodeling in A549 cells, and this enhancement was suppressed by antagonists or knockdown of CB2 or GPR55, though not CB1 receptor. Our results indicate that A2B receptors and cannabinoid CB1, CB2, and GPR55 receptors all contribute to γ-radiation-induced acquisition of malignant phenotypes, and in particular that interactions of A2B receptor and cannabinoid CB2 and GPR55 receptors play a role in promoting cell migration and actin remodeling. A2B receptor-cannabinoid receptor pathways may be promising targets for blocking the appearance of malignant phenotypes during radiotherapy of lung cancer.

Thermoluminescence properties and new insights on the UV-vis absorption features of colorless quartz after γ-ray irradiation.

In this paper, we present the results of research on the thermoluminescence (TL) and optical absorption (OA) properties of colorless natural quartz (including natural quartz samples, sodium ion (Na+) rich samples (by diffusion), and alkali metal (M+) ion poor samples (by sweep)). In detail, the relationship between the TL glow peaks and the emission wavelength was determined. The dynamics parameters (E T, s, τ) have been computed for all TL peaks on the glow curve. The recombination mechanism electron-hole with the participation of the region energy has been determined for all electron traps in the temperature range of 50-430 °C through thermally stimulated conductivity measurement (TSC). Nonlinearity and approaching signal saturation are observed at doses above 22 Gy for the electron trap at 110 °C, above 45 Gy for the electron trap at 238 °C, and 80 Gy for the electron traps at 325 °C and 375 °C. The role of irradiation and heat treatment in the formation of absorption centers as well as the relationship of these centers to electronic traps have been also investigated in detail. The role of M+ ions and hydrogen ions (H+) for the absorption bands in the UV-vis region has been discussed. The results of the combination of the TL measurement and monochromatic light absorption according to temperature show that the TL process occurs concurrently with the reduction of the absorbent center produced in the irradiation process.

A nanoarchitectured 2D–2D heterointerface of Pt@Ti3C2Tx–rGO aerogels via in situ γ-radiolysis induced self-assembly: interplay between strain and ligand effects in electrocatalytic interfaces

Exploring the interplay of strain and ligand effects at the electrocatalytic interfaces of 2D–2D Pt@Ti3C2Tx–rGO aerogel heterostructures synthesized through γ-ray irradiation.

Effects of X-ray and γ-ray Irradiations on 2D-Planar and 3D-Stacked CMOS SPADs

Effects of X-ray and γ-ray Irradiations on 2D-Planar and 3D-Stacked CMOS SPADs

Degradation Mechanism of Piezoresistive Sensors under the Influence of γ-ray Irradiation

Degradation Mechanism of Piezoresistive Sensors under the Influence of γ-ray Irradiation

Local Multiple-site Injections of a Plasmid Encoding Human MnSOD Mitigate Radiation-induced Skin Injury by Inhibiting Ferroptosis.

Most patients who undergo radiotherapy develop radiation skin injury, for which effective treatment is urgently needed. MnSOD defends against reactive oxygen species (ROS) damage and may be valuable for treating radiation-induced injury. Here, we (i) investigated the therapeutic and preventive effects of local multiple-site injections of a plasmid, encoding human MnSOD, on radiation-induced skin injury in rats and (ii) explored the mechanism underlying the protective effects of pMnSOD. The recombinant plasmid (pMnSOD) was constructed with human cytomegalovirus (CMV) promoter and pUC-ori. The protective effects of pMnSOD against 20-Gy X-ray irradiation were evaluated in human keratinocytes (HaCaT cells) by determining cell viability, ROS levels, and ferroptosisrelated gene expression. In therapeutic treatment, rats received local multiple-site injections of pMnSOD on days 12, 19, and 21 after 40-Gy γ-ray irradiation. In preventive treatment, rats received pMnSOD injections on day -3 pre-irradiation and on day 4 post-irradiation. The skin injuries were evaluated based on the injury score and pathological examination, and ferroptosis-related gene expression was determined. In irradiated HaCaT cells, pMnSOD transfection resulted in an increased SOD2 expression, reduced intracellular ROS levels, and increased cell viability. Moreover, GPX4 and SLC7A11 expression was significantly upregulated, and erastin-induced ferroptosis was inhibited in HaCaT cells. In the therapeutic and prevention treatment experiments, pMnSOD administration produced local SOD protein expression and evidently promoted the healing of radiation-induced skin injury. In the therapeutic treatment experiments, the injury score in the high-dose pMnSOD group was significantly lower than in the PBS group on day 33 post-irradiation (1.50 vs. 2.80, P < 0.05). In the prevention treatment experiments, the skin injury scores were much lower in the pMnSOD administration groups than in the PBS group from day 21 to day 34. GPX4, SLC7A11, and Bcl-2 were upregulated in irradiated skin tissues after pMnSOD treatment, while ACSL4 was downregulated. The present study provides evidence that the protective effects of MnSOD in irradiated HaCaT cells may be related to the inhibition of ferroptosis. The multi-site injections of pMnSOD had clear therapeutic and preventive effects on radiation-induced skin injury in rats. pMnSOD may have therapeutic value for the treatment of radiation-induced skin injury.

Dielectric performance improvement of polypropylene film modified by γ-ray irradiation for HVDC capacitors

Polypropylene (PP) films exhibit low dielectric strength and high losses under elevated temperatures and strong electric field environments. This paper proposes a method to improve the dielectric properties based on γ-ray irradiation crosslinking, investigates the effect of the type of sensitizer on the crosslinking reaction, and explores the effect of crosslinking structure on the dielectric properties of PP films such as breakdown strength. The results showed that the type of group in the sensitizer influenced its activity in the crosslinking reaction, and the modified films added with pentaerythritol triacrylate (PETA) exhibited the highest crosslinking degree of 25.68%. In addition, it was found that the crosslinked structure improved the stability of the molecular chains at high temperatures and reduced the probability of thermal breakdown. At 115 °C, the modified films with PETA showed a 72.5% reduction in conductivity and a 33.6% increase in breakdown strength. This method demonstrates the importance of irradiation crosslinking modification for improving the reliability of PP films in high-temperature and strong electric field applications.

Dopant concentration dependence on optical and scintillation properties of Eu-doped Gd3Al2Ga3O12 single crystals

We have studied scintillation properties of Eu3+-doped Gd3Al2Ga3O12 single crystals. Gd3Al2Ga3O12 single crystals with different concentrations of Eu3+ (0.5%, 1.0%, 5.0%, 10.0%, and 15.0%) were grown using the floating-zone method. In photoluminescence (PL) and scintillation properties, the Eu-doped Gd3Al2Ga3O12 single crystals showed emission peaks and several millisecond decay times due to 4f–4f transitions of Eu3+ ions. Pulse height spectra of all the samples were investigated under γ-ray irradiation from 137Cs (662 keV). The 0.5%, 1.0%, 5.0%, and 10.0% Eu-doped samples showed full energy peaks. Among all the samples, the 5.0% Eu-doped Gd3Al2Ga3O12 single crystal showed the highest light yield of 36 000 photons MeV−1.

Studies on Aging Behavior and Degradation Mechanism of Raw EPDM Rubber Under γ-Ray Irradiation

The aging behavior and mechanism of EPDM rubber were investigated by conducting different doses of γ-rays irradiation in raw EPDM rubber. A series of characterization methods such as Mooney viscosity, molecular weight and its distribution, rubber processing analysis, infrared spectroscopy analysis et al. were carried out. Structure and modifications of the raw EPDM rubber were tested under different irradiation doses. The results showed that the Mooney viscosity and molecular weight of EPDM rubber showed a significant decrease with increasing irradiation dose. The gel content and glass transition temperature increased gradually. As strain rose, the energy storage modulus diminished. The loss factor decreased at first and then increased with increasing strain during irradiation aging.

Effect of γ-rays irradiation on optical and structural properties of the perovskite 128° Y-cut LiNbO3 single crystal

The effect of gamma (γ) irradiation on the structural, morphological and optical properties of 128° Y-cut lithium niobate (LiNbO3) wafer was investigated. LiNbO3 samples were γ-irradiated at 60, 150 and 250 kGy by exposing them to a cobalt-60 (60C) source with a dose rate of 22 Gy/min. The Raman spectroscopy and X-ray diffraction (XRD) analyses showed that the structural changes accompanied by a slight lattice distortion of the perovskite are caused by the irradiation at 60 and 150 kGy, which recovered toward the original state for the dose 250 kGy. The AFM imaged surface morphology of the samples showed that the wafer surface is smoothed upon irradiation at 60 and 150 kGy which then recovered toward the original state at dose of 250 kGy, in agreement with the XRD analysis.

Eu concentration dependence of photoluminescence and scintillation properties on Eu-doped Y3Al5O12 single crystals

(Eux,Y1-x)3Al5O12 (x = 0.005, 0.01, 0.05, 0.10, 0.15, and 0.20) single crystals were prepared by the floating-zone method. We investigated their photoluminescence (PL) and scintillation properties including PL excitation/emission contour spectra, PL quantum yields, PL decay times, X-ray-induced scintillation spectra, scintillation decay times, and pulse-height spectra under γ-ray irradiation from 137Cs (662 keV). The PL and scintillation spectra exhibited some emission lines at visible wavelength due to the 4f-4f transitions of Eu3+ ions, and the PL and scintillation decay times resulted several milliseconds. Among all the samples, (Eu0.1,Y0.9)3Al5O12 and (Eu0.15,Y0.85)3Al5O12 single crystals showed the highest PL quantum yield. On the other hand, (Eu0.01,Y0.99)3Al5O12 single crystal showed the highest light yield. The light yield of the sample was estimated to be 36,000 photons/MeV from the pulse height spectrum.