Electron Irradiation Dose Research Articles

Optimisation of electron irradiation for creating spin ensembles in hexagonal boron nitride

Boron vacancy centre ( VB− ) ensembles in hexagonal boron nitride (hBN) have attracted recent interest for their potential as two-dimensional solid-state quantum sensors. Irradiation is necessary for VB− creation, however, to date only limited attention has been given to optimising the defect production process, especially in the case of bulk irradiation with high-energy particles, which offers scalability through the potential for creating ensembles in large volumes of material. Here we systematically investigate the effect of electron irradiation by varying the dose delivered to a range of hBN samples, which differ in their purity, and search for an optimum in measurement sensitivity. We find that moderate electron irradiation doses ( ≈5×1018 cm−2) appear to offer the best sensitivity, and also observe a dependence on the initial crystal purity. These results pave the way for the scalable and cost-effective production of hBN quantum sensors, and provide insight into the mechanisms limiting VB− spin properties.

Effect of electron irradiation on microstructural evolution and mechanical properties of Sn3Ag0.5Cu solder joints

Power electronic devices face harsh radiation environments in deep space exploration. It is significant to study the reliability of solder joints of electronic devices in radiation environments. The effect of electron irradiation on the microstructure and mechanical properties of Sn3Ag0.5Cu (SAC305) Ball Grid Array (BGA) solder joints was investigated in this work. The results show that the central position of the SAC305 solder joint surface was damaged after electron irradiation. Then the surface of the solder joints was remelted. The shear strength of solder joints increases as the electron irradiation dose rises. When the electron irradiation dose reaches 80 Mrad, the shear strength of the solder joint is enhanced by 8.62% compared with that of the unirradiated sample. After irradiation, the number of dimples on the fracture surface of solder joints increases and the depth of dimples decreases. Geant4 simulation results show that the surface of solder joint is subject to more severe electron impact than the inside of solder joint is. The interaction between electrons and solder joints is the primary reason for the surface remelting of solder joints.

Evaluation of dynamics of charge accumulation and dissipation processes in Ge15Se85 thin film under electron beam irradiation by mapping surface potential distribution

The interaction of Ge15Se85 amorphous chalcogenide films with an electron beam has been studied. Three ranges of electron irradiation doses, in which a surface relief of various shapes is formed, are found. The presence and persistence of the surface potential for a long time after film irradiation have been established using the Kelvin probe force microscopy (KPFM). It is shown that the formation of surface relief is result of the charge accumulation in the interaction region. Based on the mapping of surface potential distribution in irradiated regions using KPFM we propose models of electric field distribution in the irradiated spots and suggest mechanism of electron-induced mass transfer. It has been suggested that the formation of a high surface relief structures is due to the electron-induced plastic effect. It is shown that the appearance of asymptotically sharp Taylor cones in chalcogenide films is due to charge collapse in the interaction region when the volume charge density and internal electric field strength exceed their critical values.

Evolution of fluctuation conductivity of Y1Ba2Cu3O7-Δ single crystals under the influence of medium doses of electron irradiation and doping with praseodymium

The influence of medium doses (from 1019 cm–2 to 1020 cm–2) of irradiation with fast electrons and changes in the concentration of praseodymium in the interval 0.0 ≤ z ≤ 0.5 on the excess conductivity of optimally oxygen-doped Y1Ba2Cu3O7-δ single crystals was studied. It is shown that electron irradiation and an increase in the degree of doping with praseodymium leads to a significant expansion of the temperature interval of the existence of excess conductivity, thereby narrowing the region of the linear dependence of r(Т) in the ab-plane. It was established that at doses 0 ≤ D ≤ 6.5´1019 cm–2 the value of the value of the transverse coherence length ξс(0) increases with an increase in D approximately 3 times and more than four times as the praseodymium content in the sample increases to z ≈ 0.42. At the same time, in both cases, the 2D-3D crossover point is shifted by temperature. In contrast to the case of irradiation with small doses (D ≤ 1019 cm–2) and doping with praseodymium up to concentrations z ≤ 0.39, irradiation with medium doses and doping with praseodymium at higher concentrations leads to a non-monotonic dependence of the transverse coherence length xс(0) with characteristic maxima at D ~ (7-8)´1019 cm–2 and z ≈ 0.42, which may be related to the general suppression of superconducting characteristics.

Changes in performance and apparent ileal digestibility of broiler chickens fed diets containing electron-irradiated full-fat canola seed

Two experiments were conducted to evaluate the effect of electron-beam irradiation of canola seed on the performance and nutrient digestibility in broiler chickens. In the first experiment, the chemical composition of raw and electron-beam irradiated canola seed at doses of 10, 20, 30, and 40 kGy was characterized in order to determine the appropriate dose for the in vivo experiment. The results indicated that applied doses of electron irradiation did not affect dry matter (DM), crude fiber (CF), ash, neutral (NDF) and acid detergent fiber (ADF), crude protein (CP), and ether extract (EE) content of canola seed. Irradiation, however, decreased tannin (P < 0.01) content. Also, the glucosinolate of samples decreased by increasing irradiation dose (P < 0.01). In the second experiment, seven dietary treatments included canola seed at 5%, 10%, and 15% (raw and irradiated at 40 kGy), and a control diet was used in a completely randomized design. Birds fed 5% of irradiated canola seed had the highest feed intake during the grower (P < 0.05), finisher, and the total experiment period (P < 0.01). In the starter period, birds fed 10% of irradiated canola seed had the highest body weight gain (BWG) (P < 0.01). Birds that consumed the control diet had the highest BWG compared with the other treatments (P < 0.05) during the total experiment period. In the starter period, birds consumed the control diet, 5%, 10%, and 15% of irradiated canola seed had a better feed conversion ratio (FCR) compared to those fed raw canola seed (P < 0.01). Apparent ileal digestibility of CP, EE, and DM significantly decreased in birds fed 15% canola seed (raw or irradiated) compared to those fed other treatments (P < 0.01). In conclusion, radiation reduced glucosinolate and tannin and improved FCR in the starter period. Therefore, if high levels of canola seed (e.g., 15%) are used in the diet of broiler chickens, then radiation can be helpful.

Mechanical properties of multi-scale germanium specimens from space solar cells under electron irradiation

During long-term service in space, Gallium Arsenide (GaAs) solar cells are directly exposed to electron irradiation which usually causes a dramatic decrease in their performance. In the multilayer structure of solar cells, the germanium (Ge) layer occupies the majority of the thickness as the substrate. Due to the intrinsic brittleness of semiconductor material, there exist various defects during the preparation and assembly of solar cells, the influences of which tend to be intensified by the irradiation effect. In this work, first, Ge specimens for mechanical tests were prepared at scales from microscopic to macroscopic. Then, after different doses of electron irradiation, the mechanical properties of the Ge specimens were investigated. The experimental results demonstrate that electron irradiation has an obvious effect on the mechanical property variation of Ge in diverse scales. The four-point bending test indicates that the elastic modulus, fracture strength, and maximum displacement of the Ge specimens all increase, and reach the maximum value at the irradiation dose of 1 × 1015 e/cm2. The micrometer scale cantilever and nanoindentation tests present similar trends for Ge specimens after irradiation. Atomic Force Microscope (AFM) also observed the change in surface roughness. Finally, a fitting model was established to characterize the relation between modulus change and electron irradiation dose.

Stabilization of Diffraction Gratings Recorded in Poly-N-epoxypropylcarbazole Films Doped with Iodoform

In poly-N-epoxypropylcarbazole films containing 10 wt % CHI3 as an additive, diffraction gratings with a period of about 1 μm have been recorded by electron-beam irradiation at various radiation doses. The influence of the duration of storage in the dark of diffraction gratings on their diffraction efficiency has been examined. A postradiation increase in the diffraction efficiency of gratings recorded at relatively low electron radiation doses was observed. The diffraction efficiency values stabilized approximately on the sixth day afterrecording the diffraction gratings.

A Study of the Relationship between the Rate of Return Strain of Polytetrafluoroethylene on Time, Mechanical Stress and Dose of Electron Irradiation

The paper is devoted to the study of the influence of factors on the rate of return deformation of polytetrafluoroethylene. The dependence of the rate of return strain (ε'r) on time (t), the dose of electron irradiation (D) and mechanical stress (σ) in thin films of polytetrafluoroethylene has been experimentally investigated. Significant variations of ε'r have been found dependingon on t, D and σ. A decrease in the rate of return deformation during irradiation of the material is associated with the frictional properties between macromolecules and a change in the structure, which leads to a weaker straightening of the polymer and their poor sliding. The resulting curves for both unirradiated and irradiated material are satisfactorily described in the exponential and linear models. For dependencies ε'r on D, these are decreasing functions, and for ε'r on σ, these are increasing functions.

Hybrid Composite Materials for Immobilization of Radionuclides in Liquid Radioactive Waste

The biphasic hybrid composite materials for immobilization and fixation of radionuclides of the Liquid Radioactive Waste (LRW) of the research water-water reactor KIR WWR-K have been studied. It was found that the hybrid compositions have a high synergistic effect regard to the sorption of radionuclides, especially 137Cs+ and 134Cs+ . The distribution coefficient of cesium radionuclides in the composite materials are 2 times higher in comparison with the those sorption activity in the mineral matrix. It has been established that the sorption of radionuclides by two-phase hybrid compositions is carried out by a combination of three mechanisms. Firstly, due to the electrostatic binding reaction between the functional groups of sorbents and metal ions stabilized by the system of coordination bonds with electron-donating nitrogen and oxygen atoms of the amino and carbonyl groups of the polymer matrix. Secondly, as a result of ion exchange between counterions of the mineral matrix and radionuclides ions in the environmental solution. Finally, due to the superequimolar absorption of radionuclides as a result of deformation of the crystal lattice of mineral fillers of the polymer matrix of bentonite and copper ferrocyanide, which increases their pore size. It has been shown that biphasic hybrid composite materials have an increased mechanical and radiation resistance while retaining elasticity even at high doses of electron irradiation, at which in despite on a noticeable decrease the value of deformation there is no significant decline in their compressive strength. The obtained information on the mechanism of binding of biphasic hybrid composite materials with various metal ions makes it possible to synthesize new classes of materials for selective sorption of certain types of radionuclides in the body of mineral and polymer matrices. This will allow us to use these materials as a highly effective sorption materials with a synergetic effect for the detection, identification, immobilization and fixation of LRW radionuclides.

Analysis of 3D elemental distribution in nanomaterials: Towards higher throughput and dose efficiency.

Many advanced nanomaterials rely on carefully designed morphology and elemental distribution to achieve their functionalities. Among the few experimental techniques that can directly visualise the 3D elemental distribution on the nanoscale are approaches based on electron tomography in combination with energy-dispersive X-ray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS). Unfortunately, these highly informative methods are severely limited by the fundamentally low signal-to-noise ratio, which makes long experimental times and high electron irradiation doses necessary to obtain reliable 3D reconstructions. Addressing these limitations has been the major research question for the development of these techniques in recent years. This short review outlines the latest progress on the methods to reduce experimental time and electron irradiation dose requirements for 3D elemental distribution analysis and gives an outlook on the development of this field in the near future.

Enhancing quantum sensing performance by optimizing the concentration and dephasing time of the NV ensemble in CVD-diamond

The negatively charged nitrogen−vacancy (NV−) center ensembles in diamonds offer enormous potential for developing integrated sensors with an improved signal-to-noise ratio (SNR) and high sensitivity. However, the preparation and treatment of diamond samples with suitable NV− concentrations and dephasing time have remained challenging. This work provided insight into the NV− center formation mechanism and reconstruction via a comprehensive analysis of the concentration and dephasing time of a set of diamond samples treated by various parameters. By varying the electron irradiation dose and subsequent annealing duration, the conversion rate of nitrogen to NV− is up to 18.45%, and the corresponding maximum NV− concentration is 3.69 ppm. The dephasing time for all samples varies around 300 ns. The nitrogen-related NV− center ensemble dephasing rate per unit density is 146.4 (ppm·ms)−1, indicating that the treatment did not substantially alter the paramagnetic spin environment around the NV− center. This study not only offers support to exquisite sensitivities of NV-based sensors but also provides valuable experience for the preparation of unique properties of synthetic diamonds.

The Study of the Efficiency of Nitrogen to Nitrogen‐Vacancy (NV)‐Center Conversion in High‐Nitrogen Content Samples

The nitrogen‐vacancy color center in diamond is one of the important systems in the fast‐growing field of sensing. This color center is used in both high‐resolution and high‐sensitivity sensors. However, techniques for the quick and efficient formation of NV centers are still in the development stage. Herein, a study on the influence of the electron irradiation dose on the conversion of substitutional nitrogen into NV− centers is presented. The study is done on diamonds that are highly enriched with nitrogen (≈100 ppm), which, on one hand, should maximize the effect of irradiation, and, on other hand, be of interest for high‐sensitivity magnetometers. The maximum achieved conversion efficiency is as high as 37% ± 3.7%, with no observed saturation on the electron dose even with the simplest annealing procedure. The measurements of the corresponding dephasing time made it possible to make a theoretical estimate for the shot‐noise‐limited magnetic field sensitivity per unit volume of diamond to be roughly .

Analysis and comparison of electron radiation damage assessments in Cryo-EM by single particle analysis and micro-crystal electron diffraction.

Electron radiation damage to macromolecules is an inevitable resolution limit factor in all major structural determination applications using cryo-electron microscopy (cryo-EM). Single particle analysis (SPA) and micro-crystal electron diffraction (MicroED) have been employed to assess radiation damage with a variety of protein complexes. Although radiation induced sidechain density loss and resolution decay were observed by both methods, the minimum dose of electron irradiation reducing high-resolution limit reported by SPA is more than ten folds higher than measured by MicroED using the conventional dose concept, and there is a gap between the attained resolutions assessed by these two methods. We compared and analyzed these two approaches side-by-side in detail from several aspects to identify some crucial determinants and to explain this discrepancy. Probability of a high energy electron being inelastically scattered by a macromolecule is proportional to number of layers of the molecules in its transmission path. As a result, the same electron dose could induce much more site-specific damage to macromolecules in 3D protein crystal than single particle samples. Major differences in data collection and processing scheme are the key factors to different levels of sensitivity to radiation damage at high resolution between the two methods. High resolution electron diffraction in MicroED dataset is very sensitive to global damage to 3D protein crystals with low dose accumulation, and its intensity attenuation rates at atomic resolution shell could be applied for estimating ratio of damaged and total selected single particles for SPA. More in-depth systematically radiation damage assessments using SPA and MicroED will benefit all applications of cryo-EM, especially cellular structure analysis by tomography.

Clinical feasibility of combining intraoperative electron radiation therapy with minimally invasive surgery: a potential for electron-FLASH clinical development

BackgroundLocal cancer therapy by combining real-time surgical exploration and resection with delivery of a single dose of high-energy electron irradiation entails a very precise and effective local therapeutic approach. Integrating the benefits from minimally invasive surgical techniques with the very precise delivery of intraoperative electron irradiation results in an efficient combined modality therapy.MethodsPatients with locally advanced disease, who are candidates for laparoscopic and/or thoracoscopic surgery, received an integrated multimodal management. Preoperative treatment included induction chemotherapy and/or chemoradiation, followed by laparoscopic surgery and intraoperative electron radiation therapy.ResultsIn a period of 5 consecutive years, 125 rectal cancer patients were treated, of which 35% underwent a laparoscopic approach. We found no differences in cancer outcomes and tolerance between the open and laparoscopic groups. Two esophageal cancer patients were treated with IOeRT during thoracoscopic resection, with the resection specimens showing intense downstaging effects. Two oligo-recurrent prostatic cancer patients (isolated nodal progression) had a robotic-assisted surgical resection and post-lymphadenectomy electron boost on the vascular and lateral pelvic wall.ConclusionsMinimally invasive and robotic-assisted surgery is feasible to combine with intraoperative electron radiation therapy and offers a new model explored with electron-FLASH beams.

Permittivity modulation in Si-based PIN diode by electron irradiation

In this paper, we investigate the influence of defects induced by different doses of electron irradiation on the real part of permittivity of Si-based PIN diodes with a deep-level transient spectrum test. For a more precise result, the relationship between the real part of the permittivity of the sample and the irradiation dose, temperature and annealing is studied. The results show that the real part of the permittivity changes significantly with the irradiation dose and temperature. The absolute value of the real part of the permittivity decreases with the decrease in temperature, and the changing trend decreases after annealing. The deep-level transient spectroscopy results illustrate that different states of defects caused by radiation and annealing have changed the free carrier mobility, free carrier density and charge balance in the material, which means they have a significant impact on the electrical characteristics of the samples. The I–V and C–V curves are obtained through experiments to extract the leakage current and carrier concentration. The I–V characteristic and the permittivity are subjected to temperature-variation analysis.

Influence of 8 MeV Electron Irradiation on the Properties of ZnO Nanocrystalline Thin Films for Optoelectronic Devices in the High Radiation Environment

Herein, we present the influence of 8 MeV electron beam irradiation on the structural, optical and electrical properties of sol-gel derived spin-coated ZnO films. The electron irradiation doses varied from 0 kGy to 10 kGy. We observed significant changes in the morphology, optical and electrical properties of the films upon irradiation. Structural analysis of the films revealed the preferential and dominant c-axis orientation of the crystallites along the (002) plane. The preferential growth of the films was also supported by the values of texture coefficient. Atomic Force Microscopy studies reveal the linear relationship between the surface roughness, grain size and irradiation dose. The average transmittance of the films decreased from 87% to 66% after irradiation. A slight red-shift of the optical band gap values was observed when the absorbed dose was increased from 0 kGy to 10 kGy. The Photoluminescence measurement of the films showed that the intensity of the defect-related peak increases with the electron dose. The electrical resistivity of the films decreased after irradiation and a minimum resistivity of 7.566 × 10−2 Ω m was obtained from the film irradiated with a 5 kGy electron dose. To find the performance and quality of the prepared film, the Figure of Merit was calculated and was found that the film irradiated with a 5 kGy electron dose shows the maximum value. The obtained results show that electron irradiation is a potential alternative approach to improve the performance of the ZnO films for optoelectronic devices in a high radiation environment.

DNA mapping in the capsid of giant bacteriophage phiEL (Caudovirales: Myoviridae: Elvirus) by analytical electron microscopy

Giant phiKZ-like bacteriophages have a unique protein formation inside the capsid, an inner body (IB) with supercoiled DNA molecule wrapped around it. Standard cryo-electron microscopy (cryo-EM) approaches do not allow to distinguish this structure from the surrounding nucleic acid of the phage. We previously developed an analytical approach to visualize protein-DNA complexes on Escherichia coli bacterial cell slices using the chemical element phosphorus as a marker. In the study presented, we adapted this technique for much smaller objects, namely the capsids of phiKZ-like bacteriophages. Following electron microscopy techniques were used in the study: analytical (AEM) (electron energy loss spectroscopy, EELS), and cryo-EM (images of samples subjected to low and high dose of electron irradiation were compared). We studied DNA packaging inside the capsids of giant bacteriophages phiEL from the Myoviridae family that infect Pseudomonas aeruginosa. Phosphorus distribution maps were obtained, showing an asymmetrical arrangement of DNA inside the capsid. We developed and applied an IB imaging technique using a high angle dark-field detector (HAADF) and the STEM-EELS analytical approach. Phosphorus mapping by EELS and cryo-electron microscopy revealed a protein formation as IB within the phage phiEL capsid. The size of IB was estimated using theoretical calculations. The developed technique can be applied to study the distribution of phosphorus in other DNA- or RNA-containing viruses at relatively low concentrations of the element sought.

Feasibility Study of Mesoporous Silica MCM-41 Functionalization by Electron-Beam Irradiation

Abstract Mobil Composition of Matter No. 41 (MCM-41) is a member of the mesoporous silica family, which is used as an inhomogeneous catalyst in many chemical processes because of its large surface and also its uniform channels. MCM-41 is used to transport material in reactions and targeted drug-delivery systems, especially blood-disorders medication. The purpose of this study was to functionalize MCM-41 by electron beam irradiation to achieve optimal irradiation conditions to be used as the primary catalyst for the intelligent transfer of new drugs in hematology. Functionalized MCM-41 with 3-aminopropyltriethoxysilane (APTS), 3-methoxybenzyl alcohol, 2-nitrobenzyl alcohol, 4-nitrobenzyl alcohol, 2,4-dinitrobenzyl alcohol, and 3-chlorobenzyl alcohol are suitable compounds for medical and drug delivery purposes in different parts of the body. To this end, MCM-41 was first synthesized by the sol-gel method, and then using Fourier-transform spectroscopy, the functionalization of its compounds, the effects of electron dose on it, and the effect of different reactants on its production were examined. To functionalize MCM-41, the applied electron irradiation dose and the type of alcohol are very important components that ultimately the optimal dose and the appropriate process for alcohol reaction will be suggested to be functionalized. In optimum irradiation conditions, 3-APTS, 3-methoxybenzyl alcohol, 2-nitrobenzyl alcohol, 4-nitrobenzyl alcohol, and 2,4-dinitrobenzyl alcohol were successfully grafted onto MCM-41, which can be used as controlled drug delivery systems. The use of the electron irradiation method for the functionalization of mesoporous silica compounds has many advantages over similar chemical methods, namely no use of chemicals, high-reaction speed, higher efficiency, and lower-chemical contamination.

Investigations on electron beam irradiated rare-earth doped SrF2 for application as low fading dosimeter material: evidence for and DFT simulation of a radiation-induced phase

A recent approach to measure electron radiation doses in the kGy range is the use of phosphors with an irradiation dose-dependent luminescence decay time.

Electrical Properties of Selectively Deposited Graphene‐Like Film on Silicon Oxide/Silicon Structures Preirradiated with Low Energy Electrons

Graphene‐like films (GLFs) are selectively deposited on the silicon oxide/silicon structures preirradiated with electrons at various electron energies and irradiation doses. These films demonstrate high conductivity and are used as a gate material for metal‐oxide‐semiconductor (MOS)‐based devices. It is shown that high‐quality capacitance–voltage characteristics of the GLF‐gated MOS structures can be obtained if both an energy and a dose are carefully tuned. Using the GLF‐gated MOS as a pseudo‐field effect transistor structure, a notable current modulation in the selectively grown GLF is observed.