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Together with the mechanical properties, the degradation rate is an important factor for biodegradable implants. The ZKX50 Mg alloy is a suitable candidate to be used as a biodegradable implant due to its favorable biocompatibility and mechanical properties. Current research investigates the degradation rate and corrosion behavior of the ZKX50 as a function of the microstructure constituents and their morphology. Since grain refinement is the main strengthening mechanism for the ZKX50, the effect of the microstructure refinement on the corrosion rate was studied by applying electron beam processing (EBP) and friction stir processing (FSP) on the ZKX50 cast alloy. To study the effect of the microstructure constituents and their morphology a subsequent solution heat treatment (HT) was applied to the processed samples. The results show that the EBP and FSP lead to a uniform and remarkably refined microstructure of the ZKX50 alloy and homogeneous distribution of the intermetallic phases. The results of electrochemical corrosion tests together with the microstructure characterization show that microgalvanic corrosion is the predominant mechanism that occurs between the Ca2Mg6Zn3 intermetallic phase and α-Mg matrix. According to the results attained through the electrochemical tests, the EBPed-HT ZKX50 alloy shows higher corrosion resistance compared to all other conditions immersed in 0.5 wt% NaCl solution. The dissolution and spheroidizing of Ca2Mg6Zn3 particles during the solution heat treatment provides higher corrosion resistance mainly by decreasing the microgalvanic corrosion. The microstructure of the heat-treated samples does not show a significant grain coarsening which can degrade the enhancement of the mechanical properties achieved by the EBP and FSP.

Zirconium Carbide (ZrCx) was irradiated with 10 MeV Au3+ ions to a dose of 10 displacements per atoms (dpa) and subsequently with 100 and 300 keV electrons in a transmission electron microscope (TEM). After ion irradiation, dislocation loops were observed in the microstructure and an increase in the number of carbon vacancies was revealed by Raman spectroscopy. Grazing incidence X-ray diffraction (GIXRD) analysis showed that neither amorphization nor oxidation occurred during ion irradiation of the specimen. Subsequent electron irradiation of the pre-implanted ZrCx foil led to formation of nanosized tetragonal ZrO2 precipitates (5−10 nm diameter) on the surface of the TEM lamella. The formation of the new oxide phase was not related to the electron beam-induced heating of the specimen, but to electron stimulated oxidation caused by the residual oxygen inside the transmission electron microscope. Changes in size and density of ZrO2 crystallites were observed between the pristine and ion irradiated ZrCx regions following electron irradiation, suggesting that the initial microstructure of the ZrCx substrate played a key role in the nucleation and growth of the oxide islands. The obtained results provide insights into the microstructural response of ZrCx to different types of radiation and the inadvertent effects of the electron beam during TEM analysis of in-situ and ex-situ ion irradiated ZrCx. Additionally, the findings of this work suggest a method to prepare local ZrO2 nanoprecipitates within ZrCx grains by selective electron beam irradiation.

A promising magnetocaloric effect has been obtained in Ni-(Co)-Mn-X (X = Sn, In, Sb)-based Heusler alloys, but the low isothermal magnetic entropy change ΔSM restricts the further promotion of such materials. Defect engineering is a useful method to modulate magnetic performance and shows great potential in improving the magnetocaloric effect. In this work, dense Ni vacancies are introduced in Ni41Mn43Co6Sn10 alloys by employing high-energy electron irradiation to adjust the magnetic properties. These vacancies bring about intense lattice distortion to change the distance between adjacent magnetic atoms, leading to a significant enhancement of the average magnetic moment. As a result, the saturation magnetization of ferromagnetic austenite is accordingly improved to generate a high isothermal magnetic entropy change ΔSM of 20.0 J/(kg K) at a very low magnetic field of ∼2 T.

With the advancement of three-dimensional electronic technologies, 3D betavoltaics consisting of a mixture of a semiconductor converter and a beta emitter have been investigated to increase output power by maximizing the beta absorption in the semiconductor. Semiconductor radiation robustness has typically been evaluated by monitoring electrical properties during the beta irradiation process over a long dwell time. To quickly and safely assess semiconductor candidates for betavoltaics without incorporating high-activity beta emitters, a custom-designed electron beam system as a beta source surrogate has been used. In this work, we report the change of electrical performance of planar 4H-SiC, planar Si, and 3D Si ridge p-i-n diodes irradiated by high-flux and high-fluence electrons. The 4H-SiC diodes were found to suffer 45% degradation to output power with 100 keV electron irradiation at a fluence of 1.3 × 1018 cm−2; however, the Si diodes showed no decrease in performance at the highest fluence of 100 keV electron irradiation of 7 × 1018 cm−2. This demonstrates that Si is more radiation hard than 4H-SiC for 147Pm-based betavoltaics, with an average beta energy of 62 keV.

Dust hazards are considered to be one of the technical challenges for future lunar exploration. In our past work a new dust mitigation technology was introduced utilizing an electron beam to remove dust particles from various surfaces. This technology was developed based on a patched charge model, which shows that the emission and re-absorption of electron beam induced secondary electrons inside microcavities between dust particles can lead to sufficiently large charges on the dust particles, causing their release from the surface due to strong repulsive forces. In this paper an improvement in the effectiveness of this technology is demonstrated with varying the beam incident angle on dust-covered sample surfaces by rotating the samples relative to the beam. Due to random arrangements of the microcavities, more of them will be exposed to the beam with various incident angles, thereby causing more dust release from the surface. The cleaning performance is tested against three samples: glass, spacesuit, and a photovoltaic (PV) panel. Lunar simulant (

The aging of Y1Ba2Cu3O7-δ thin film structures after low energy 30 keV electron irradiation has been investigated. The irradiation was aimed at creating artificial channels with suppressed superconductivity that would enforce the coherent flow of vortices. Through transport measurements, the irradiated regions were found to degrade gradually with the time of aging contrary to non-irradiated parts with good time stability of superconducting properties. Raman spectroscopy and atomic force microscopy investigations have revealed the presence of a relatively thick carbon contamination layer on the top of YBCO films originating from electron irradiation. X-ray photoelectron spectroscopy analysis supported by the evolution of Raman spectra suggests that carbon penetrating YBCO structures may be responsible for chemical interaction with the YBCO species to form C-O bonds, following the time evolution of the Raman spectra.

In this paper, the distribution of the electric field of medium voltage (MV) underground cable insulation made of polyethylene/copper nanoparticles (XLPE/Cu) is investigated. Three methods were est...

The effect of pulsed ion-plasma irradiation in the Plasma Focus Vikhr setup and irradiation with 20-MeV electrons at the Microtron-ST accelerator on the mechanical properties of the Inconel 718 precipitation-hardened alloy obtained by the selective laser fusion method has been studied. It was found that ion-plasma and electron irradiation does not affect the properties of the alloy, which is explained by the small thickness of the modified layer during irradiation at the Plasma Focus setup and insufficiently high electron fluence for the manifestation of radiation-stimulated process of redistribution and dissolution of dispersed precipitates of the strengthening phases. The results obtained bear evidence of a high resistance to crack propagation and the absence of a tendency of the studied alloy to embrittlement.

Three dimensional (3D) porous graphene can prevent restacking of graphene sheets and enables easy access and diffusion of ions, which affords possibility to fill the gap between laboratory research and industrialization of graphene. However, efficient synthesis of macroscopic thick 3D porous graphene films is still a challenge. Here, a novel strategy is firstly reported to straightforward synthesize 3D graphene, by high-energy e-beam induction on polyimide (PI). Due to high kinetic energy and low reflection features, energy of e-beam can be readily absorbed, leading to carbonization of PI and formation of macroscopic thick graphene films (0.66 mm) with abundant 3D pore structures and desirable electrical conductivity of 1100 S m−1. Meanwhile, the few-layer structure, low defects, high quality, and rapid synthesis speed (84 cm2 min−1), enable the as-obtained e-beam induced graphene (EIG) film to possess the potential for large-scale applications. Performances of EIG in energy storage and photothermal deicing have been explored. The EIG supercapacitor shows an impressive specific areal capacitance of 67.1 mF cm−2 at 0.1 mA cm−2. Besides, EIG exhibits desirable and eco-friendly photothermal deicing capability at −40 °C. This methodology exhibits wide applicability in pursuing concepts of fast, simple and low-cost for 3D graphene manufacturing and multidisciplinary applications.

Binary potassium silicate glass 15K2O·85SiO2 was prepared in the form of a thin foil and was irradiated with electrons in the transmission mode. A defocused beam of 10, 20, 30, and 50 keV energy was used to prevent a significant temperature increase. Both, the front and back surfaces were depleted of potassium by the irradiation, but not to the same extent; the front surface was quickly fully depleted of potassium, but the backside only partially. The potassium depth distribution was not consistent with the assumed shape of the electric field established in the solid, but was significantly shifted from the middle of the foil. The found asymmetry is due to the momentum transfer from the elastic scattering of the incident electron to the potassium ion, which acts as an additional effective force.

Kazuhisa Sato and Hirotaro Mori, Athermal Solid Phase Reaction in Pt/SiOx Thin Films Induced by Electron Irradiation, ACS Omega, 2021, 6 (33), 21837-21841., Microelectronics based on Si requires metal silicide contacts. The ability to form platinum silicide (Pt₂Si) by electronic excitation instead of thermal processes would benefit the field. We studied the effects of electron irradiation on Pt₂Si formation in composite films-composed of Pt and amorphous silicon oxides (a-SiOx)-by transmission electron microscopy and electron diffraction. Pt₂Si formed in Pt/a-SiOx bilayer and a-SiOx/Pt/a-SiOx sandwiched films by 75 keV electron irradiation, at 298 and 90 K. The reaction is attributable to dissociation of SiOx triggered by electronic excitation. In a-SiOx/Pt/a-SiOx sandwiched films, reflections of pure Pt were not present after irradiation, i.e., Pt was completely consumed in the reaction to form Pt₂Si at 298 K. However, in Pt/a-SiOx bilayer films, unreacted Pt remained under the same irradiation conditions. Thus, it can be said that the extent of the interfacial area is the predominant factor in Pt₂Si formation. The morphology of Pt islands extensively changed during Pt₂Si formation even at 90 K. Coalescence and growth of metallic particles (Pt and Pt-Si) are not due to thermal effects during electron irradiation but to athermal processes accompanied by silicide formation. To maintain the reaction interface between metallic particles and the dissociation product (i.e., Si atoms) by electronic excitation, a considerable concomitant morphology change occurs. Elemental analysis indicates that the decrease in Si concentration near Pt is faster than the decrease in O concentration, suggesting formation of a Si depletion zone in the amorphous silicon oxide matrix associated with formation of Pt₂Si.

International audience; The degradation of InGaAsN pin subcell under 1 MeV electrons irradiation was studied by characterizing solar cells and dilute nitride bulk layers before and after irradiation. Cells are measured to retain more than 94 % of their original photocurrent after 10 15 cm-2 1 MeV-electrons irradiation. Moreover, no significant degradation of the optoelectronic properties is observed after irradiation.

The effects of high-energy (1 MeV) electron irradiation on the electrical and trapping properties of AlGaN/GaN high-electron-mobility transistors (HEMTs) are investigated systematically. When the irradiation fluence increases from ${5} \times {10}^{{12}}$ /cm2 to ${1} \times {10}^{{14}}$ /cm2, the drain–source current also increases and the threshold voltage shifts toward the negative direction. A Raman spectroscopy study shows that electron irradiation induces strain relaxation in the HEMT, which results in an improvement in the device’s electrical characteristics. In particular, three traps in the device are identified using the voltage-transient method and the trapping effects in the HEMT are investigated after the final irradiation. When compared with the transient voltages during the pristine stage, the absolute amplitudes of the three traps in the device decrease after irradiation, which indicates a reduction in the density of the traps. Furthermore, it is proposed that the time constants of the three traps increase while the energy levels remain unchanged, which is ascribed to the strain relaxation and the structural ordering of the defects after electron irradiation. The observed changes in the trapping behaviors are consistent with the improvement in the electrical properties of the device and the shift in the Raman spectra.

Highly conductive carbon-based thin films have been produced by low-energy electron irradiation. Low-energy electron irradiation at a lower density of electrons eliminates the sp3 hybridization of the carbon atoms by reducing the chemical groups on the surface. Irradiated carbon-based thin films became highly conductive layers that could be used as electrodes for optoelectronic devices. The electrical conductivity σ reached 3 × 104 S/m in the case of samples irradiated at a lower density, with a mean value between 3 × 105 S/m and 3.3 × 102 S/m for highly crystalline graphite structures. The increasing (002) peak diffraction and decreasing intensity ratio ID/IG in the Raman spectra as well as the decreasing bandgap in photoluminescence measurements demonstrated the reduction of oxygen-induced defects in these thin films.

A deep dielectric charging model of a solar array drive assembly (SADA) under the coupling effect of electron irradiation and operating voltage is established based on the bipolar charge transport process. The distribution of space charge, potential and electric field in SADA are simulated and analyzed under three different operating conditions, i.e., flux model for internal charging (FLUMIC) spectrum electron irradiation acting alone; operating voltage acting alone; electron irradiation and operating voltage coupled. The effects of electron flux enhancement, electron direction, and operating voltage on charging properties are studied. Based on these investigations, discharge risk and location are pointed out. In the case of electrons incident from the end surface acting alone, much more space charge will accumulate than that from the columnar surface, and the maximum electric field will be above 108 V/m when the flux enhancement exceeds 100. When the operating voltage acts alone, the maximum electric field will not exceed 107 V/m as long as the operating voltage is below 8772 V. Under typical spectrum, the maximum electric field under coupling effect increases linearly as the operating voltage increases. When the electron flux enhancement increases to 100 and 1000, the electron irradiation dominates the deep charging characteristic. This provides theoretical guidance for the methods of discharge containment in SADAs.

A combination of electroexplosive spraying, electron-beam treatment, and nitriding is used to obtain a coating based on silver, copper, and tungsten carbides and nitrides. The structure and phase composition of the coatings are studied by contemporary means of physical materials science (X-ray phase analysis plus scanning and transmission electron microscopy). Wear resistance, hardness, the coefficient of friction, and resistance to electroerosion are determined.

The electron diffraction investigation of two-component phases in the systems MF2–RF3 (CaF2–ErF3, SrF2–LaF3) and components of the systems CaF2, SrF2, BaF2, and LaF3 is performed in a transmission electron microscope. The effect of electron irradiation, causing decomposition of metal fluorides with elimination of fluorine and transformation of the formed metal into oxide, is demonstrated. The crystal structure of the ordered tysonite (structural type LaF3) phase of the composition Er0.7Ca0.3F2.7, characterized by complete cation ordering and a low fluorine-ion conductivity, is identified. A nanostructured state of the tysonite phase La1 – ySryF3 – y (y = 0.10, 0.15), comprised of a tysonite matrix and lamellar interlayers of a phase enriched with strontium, is established. The formation of lamellar interlayers is responsible for the decrease in the ionic conductivity of the tysonite phases La1 – ySryF3 – y with an increase in the content of strontium after the conductivity peak at y = 0.05.

Microwave synthesized nano-sized Cu2ZnSnS4 (CZTS) powder was irradiated with 6 MeV electrons, to investigate stability under radiation. The structural, optical, vibrational and morphological properties were explored using X-ray diffraction, UV–Visible spectroscopy, Raman spectroscopy and scanning electron microscope (SEM). The irradiated sample shows significant change in properties when compared with the pristine sample. X-ray peak broadening analysis has been used to estimate the crystallite size and lattice strain. Raman spectroscopy analysis confirms the transition of ordered kesteriteto disordered kesterite phase after electron irradiation at electron fluence of 4 × 1015 e−/cm2. CZTS nanoparticles having hierarchical flower-like morphology starts agglomerating after electron irradiation as observed from SEM images. The sample did not amorphize up to the highest fluence4 × 1015 e−/cm2employed in this study.

The diffuse reflection spectra (in the range of 300–1000 nm) of polypropylene modified with aluminum-oxide nanoparticles in the concentration range of 1–5 wt %, its integrated absorption coefficient of solar radiation, as well as their change after electron irradiation (E = 30 keV, Φ = 2 × 1016 cm–2) are studied. The optimal concentration of nanoparticles (2 wt %), at which the radiation resistance increases by 9.5 times, is established. The results of this study can be used for the selection of materials that work under the influence of ionizing radiation in outer space, in nuclear power plants, and in accelerator and X-ray facilities.

The CdTe solar cell engineering is still lacking maximum achievable power conversion efficiency as predicted based upon the detailed balance. In device development, each constituent layer plays important role and to reduce open-circuit voltage loss, the reduction of back surface recombination is a promising approach. It could be made by introducing a wide-band gap ZnTe layer between the absorber CdTe layer and metal contact which can solve the issue of the Schottky barrier at the interface. The ZnTe layers also need optimization to the physical properties to implicate in CdTe-based device and therefore, the present work reports annealing and thickness evolution to ZnTe films to seek their feasibility as rear contact material where 200 nm and 300 nm thin ZnTe films are developed employing e-beam evaporation and subsequently annealed at 100 °C, 200 °C and 300 °C in air ambient followed by characterizations by amicable tools for exploration of relevant physical properties. Findings demonstrate that the film thickness and annealing temperature have considerably affected the physical properties of the developed films and the 200 nm ZnTe thin films annealed at 100 °C may be implicated as rear contact material in CdTe solar cell devices.

This paper presents the results from a study on the effect of 10 MeV electron irradiation on polyimide (PI)–tungsten oxide W O 2 composites. The electron flux (fluence rate) was 3.5 × 1 0 15 electrons c m −2 se c −1 . A single absorbed dose varied between 10 − 20 kGy with the maximum total absorbed dose being 10 MGy . The morphological, physicomechanical, and dielectric properties of the samples were studied before and after irradiation with fast electrons, at various accumulated doses. It was found that irradiation with electrons at the maximum dose leads to an increase in the roughness of the PI surface, with an increase in average roughness from 28 to 46 nm, and for the PI/W O 2 composite the roughness is practically unchanged, from 55 nm pre-irradiation to 58 nm post-irradiation. Irradiation of PI with fast electrons increases its Vickers microhardness by 39%, while that of the PI/W O 2 composite decreases by 10% post-irradiation. At a maximum absorbed dose of 10 MGy , the dielectric constant PI decreases by almost 20%, while fast electron irradiation of the PI/W O 2 composite has practically no effect on the dielectric constant.

The electroerosion-resistant coatings of CuO–Ag and ZnO–Ag systems were obtained on the Cu surface. The formation of the coating was caused by the processing of copper surface with a plasma formed in the electrical explosion of silver foil with a weighed sample of copper oxide or zinc oxide. After electroexplosion spraying, the electron-beam treatment of coatings was performed. The nanohardness, Young modulus, wear resistance, friction coefficient, and electrical erosion resistance of the formed coatings were studied. All studied properties exceed those of copper. Electrical erosion coatings were studied by the methods of scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. It became possible to achieve the high level of operational properties of electrical erosion coatings due to their nanostructurization. Structure of coating is formed by cells of high-speed crystallization. The size of cells varies within the range from 150 nm to 400 nm. The cells are separated by interlayers of the second phase whose thickness varies as 15–50 nm. By method of atomic force microscopy, the separate particles of ZnO or CuO of different shapes and 10–15 nm in size chaotically located in silver matrix were revealed as well as spherical particles of ZnO or CuO in size of 2–5 nm. The total thickness of coatings is 60 μm. The complex of studies we have carried out permits to recommend the integrated processing for strengthening the switch copper contacts of powerful electrical networks.

Organo-halide perovskite solar cells (PSCs) are lightweight and low cost, and they offer high power conversion efficiencies. PSCs have proven to be useful in terrestrial applications. In addition, they are particularly attractive for space applications because they can offer a higher radiation tolerance than GaAs and Si solar cells. This paper evaluates the damage coefficient for minority carrier diffusion length KL of perovskite crystals after 1 MeV electron irradiation by time-resolved photoluminescence measurements to investigate the reason for their high radiation tolerance. Results show that perovskite crystals have a lower damage coefficient KL than that of InP crystals with a high radiation tolerance. On the other hand, first-principles calculations indicate that the displacement energy of perovskite crystals is as low as that of Si, which does not have a high radiation tolerance. The present results suggest that the annealing effect occurs for PSCs at room temperature.

The stability of the molecular self-assembled monolayers (SAMs) is of vital importance to the performance of the molecular electronics and their integration to the future electronics devices. Here we study the effect of electron irradiation-induced cross-linking on the stability of self-assembled monolayer of aromatic 5,5′-bis(mercaptomethyl)-2,2′-bipyridine [BPD; HS-CH2-(C5H3N)2-CH2-SH] on Au (111) single crystal surface. As a refence, we also study the properties of SAMs of electron saturated 1-dodecanethiol [C12; CH3-(CH2)11-SH] molecules. The stability of the considered SAMs before and after electron-irradiation is studied using low energy Ar+ cluster depth profiling monitored by recording the X-ray photoelectron spectroscopy (XPS) core level spectra and the UV-photoelectron spectroscopy (UPS) in the valance band range. The results indicate a stronger mechanical stability of BPD SAMs than the C12 SAMs. The stability of BPD SAMs enhances further after electron irradiation due to intermolecular cross-linking, whereas the electron irradiation results in deterioration of C12 molecules due to the saturated nature of the molecules. The depth profiling time of the cross-linked BPD SAM is more than 4 and 8 times longer than the profiling time obtained for pristine and BPD and C12 SAMs, respectively. The UPS results are supported by density functional theory calculations, which show qualitative agreement with the experiment and enable us to interpret the features in the XPS spectra during the etching process for structural characterization. The obtained results offer helpful options to estimate the structural stability of SAMs which is a key factor for the fabrication of molecular devices.

A continuous electron beam scanning process was used for the surface treatment on U-5.5Nb alloy, under various combinations of beam current, beam accelerating voltage, and scanning speed. The transverse cross-section characteristics of the resulting modification layers were metallographically measured to investigate the relationship between the electron beam processing parameters and the fusion zone geometry or the resolidification microstructure. Results showed that the resolidified modified layers were obtained with the bulk energy density (E0*) value exceeding 60.7 J/mm3. An “equiaxed-columnar-equiaxed” sandwich-type grain structure was formed in the resolidification fusion zone under the effects of local temperature gradient (G) and the growth rate (R). Different from that of traditional surface modified alloys, the cross-sectional microstructure of surface modified U-5.5Nb alloy consists of four characteristic areas: fusion zone (FZ), heat affected zone (HAZ), base metal (BM), and partially fusion zone (PFZ). The width (W) and depth (D) of the fusion zone had an almost linear increase with the bulk energy density (E0*). The Vickers hardness, Nb composition, and phase microstructures were also examined. The surface hardness values increased significantly following surface treatment, which was mainly attributed to phase transformation.

Differential scanning calorimetry is used to study the effect doses of electron irradiation on the structural state of composite materials synthesized from mechanochemically obtained precursors of ultrahigh molecular weight polyethylene and boron carbide В4С. Powdered composite precursors are hot-pressed to prepare the plates for electron-beam irradiation experiments. Specimens were irradiated at RT conditions using the U-10 2 MeV electron accelerator at the Baikov Institute’s radiation facility. The composites were investigated by means of DSC method to determine polymer crystallinity and intra-chain cooperative effects on melting. Changes in the structural and morphological characteristics of composite samples have been examined via scanning electron microscopy, X-ray diffraction, and FTIR spectroscopy investigations. Analysis of the data shows that the studied composite material is resistant to electron irradiation fluences of up to 8 × 1014 cm–2.

The study of the deformation characteristics of thin polymer films has established 2 stages of increasing strain with increasing stress: the first stage in the elastic region is slow linear; the second stage is sharply exponential. The dependence of deformation (ε) on stress (σ) in polytetrafluoroethylene at various exposure doses has been experimentally investigated. Irradiation of the fluoroplastic films under study with electrons doses of 1, 3, 5, 7, and 10 kGy leads to significant changes in their mechanical properties, while the samples lose their plasticity and begin to break at a lower strain, which is associated with the formation of nanodefects in the structure of the material. A significant decrease in elongation is observed compared with unirradiated material. The reason for this is the degradation of the main chains of the fluoroplastic. With an increase in the absorbed dose, the Young's modulus increases exponentially, which is associated with a decrease in the distance between atoms in the structure of the sample. The resulting effect can be used in industry. The curves obtained for both non-irradiated and irradiated material are satisfactorily described in the exponential model.

In order to study the effect of high-energy electrons on the structure of SiO2 film for gate dielectric. A kind of complex structure SiO2 film was irradiated under 1 MeV electron irradiation with different fluences. The changes in composition, microstructure and phase distribution of the SiO2 film surface induced by the 1 MeV electrons were characterized by Raman scattering spectroscopy (Raman), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The Raman scattering and TEM results show that the amorphous silicon (α-Si) is formed on the surface of the SiO2 film after 1 MeV electron irradiation. However, the amorphous silicon does not appear after 90 keV electron irradiations. Based on the comparison for different energy electrons, it can be believed that the formation of amorphous silicon is attributed to the displacement of oxygen atoms as s result of 1 MeV electron irradiation. In addition, XPS analyses show that the double-oxygen ions are formed in the surface layer of the SiO2 film after the irradiation.

In this paper, the degradation related parameters of GaInP/GaAs/Ge triple-junction solar cell induced by electron irradiation are carried out by numerical simulation. The degradation results of short-circuit current, open-circuit voltage, maximum power have been investigated, and the degradation mechanism is analyzed. Combining the degradation results, the degradation of normalized parameters versus displacement damage dose is obtained. The results show that the degradation increases with the increase of the electron fluence and electron irradiation energy. The degradation normalized related parameters versus displacement damage dose can be characterized by a special curve that is not affected by the type of irradiated particles. By calculating the annual displacement damage dose and the on-orbit operation time of special space orbit, the degradation of normalized parameters can be obtained with the fitting curve in the simulation. The study will provide an approach to estimate the radiation damage of triple-junction solar cell induced by space particle irradiation.

The ever-increasing space exploration enterprise calls for novel and high-quality radiation-resistant materials, among which nonlinear optical materials and devices are particularly scarce. Two-dimensional (2D) materials have shown promising potential, but the radiation effects on their nonlinear optical properties remain largely elusive. We previously fabricated 2D bismuthene for mode-locking sub-ns laser; herein, their space adaption was evaluated under a simulated space radiation environment. The as-synthesized thin layers of bismuthene exhibited strong third-order nonlinear optical responses extending into the near-infrared region. Remarkably, when exposed to 60Co γ-rays and electron irradiation, the bismuthene showed only slight degradation in saturable absorption behaviors that were critical for mode-locking in space. Ultrafast spectroscopy was applied to address the radiation effects and damage mechanisms that are difficult to understand by routine techniques. This work offers a new bottom-up approach for preparing 2D bismuthene, and the elucidation of its fundamental excited-state dynamics after radiation also provides a guideline to optimize the material for eventual space applications.

The effect of electron irradiation on the evolution of the structure and creep of the samples Zr1Nb alloy of industrial production and samples obtained by the IPD method were studied. It was shown that irradiation with electrons with a dose not exceeding D = 5∙1019 сm–2 does not affect the plastic deformation mechanisms of the industrial Zr1Nb alloy, as a result of which its high thermomechanical and radiation stability is maintained. Irradiation by electrons with an energy of E = 10 MeV and doses of D = 6∙1017 and 5∙1019 сm–2 does not change the character of the deformation nanostructure of the Zr1Nb alloy, but initiates return processes in grain boundaries and boundary regions and cause the changes in crystalline anisotropy of GPU lattice, which leads to softening of the material during creep at 380 °C.

Purpose To evaluate the effects of electron-beam (E-beam) irradiation on the human cornea and the potential for E-beam sterilization of Boston keratoprosthesis (BK) devices when pre-assembled with a donor cornea prior to sterilization. Methods Human donor corneas and corneas pre-assembled in BK devices were immersed in recombinant human serum albumin (rHSA) media and E-beam irradiated at 25 kGy. Mechanical (tensile strength and modulus, and compression modulus), chemical, optical, structural, and degradation properties of the corneal tissue after irradiation and after 6 months of preservation were evaluated. Results The mechanical evaluation showed that E-beam irradiation enhanced the tensile and compression moduli of human donor corneas, with no impact on their tensile strength. By chemical and mechanical analysis, E-beam irradiation caused a minor degree of crosslinking between collagen fibrils. No ultrastructural changes due to E-beam irradiation were observed. E-beam irradiation slightly increased the stability of the cornea against collagenase-induced degradation and had no impact on glucose diffusion. The optical evaluation showed transparency of the cornea was maintained. E-beam irradiated corneal tissues and BK-cornea pre-assembled devices were stable for 6 months after room-temperature preservation. Conclusions E-beam irradiation generated no detrimental effects on the corneal tissues or BK-cornea pre-assembled devices and improved native properties of the corneal tissue, enabling prolonged preservation at room temperature. The pre-assembly of BK in a donor cornea, followed by E-beam irradiation, offers the potential for an off-the-shelf, ready to implant keratoprosthesis device.

The design and operation of an experimental installation are described, used for simulating those factors that most greatly affect the properties of materials and microelectronic devices in conditions of the near Earth (Low Earth Orbit) environment. The simulator apparatus is in the form of a cylindrical metal vacuum chamber constructed and mounted to the electron accelerator facility of the Center for the Advancement of Natural Discoveries using Light Emission Synchrotron Research Institute (Armenia) which allows the production of accelerated electrons with the following parameters: ultra-short pulse duration (τ = 4·10−13 s), electron energy 3.5 MeV, pulse current intensity 60 A/cm2, pulse frequency 12 Hz. A comparison may be made with conventional electron accelerators, which employ micro-second pulse duration, and a far lower current intensity of 2∙10−3 A/cm2. Thus, the specific features of this installation enable the simulation of ultra-fast processes as occur in cosmic space or under other extreme conditions. Here, we present the initial results obtained, concerning the influence of high-density electron irradiation on the behavior of the electro-physical properties of silicon crystals. Peculiarities and differences are presented between the results obtained from silicon crystals irradiated by electrons with an energy of 3.5 MeV and a pulse duration of τ = 4·10−13 s, and those from silicon samples irradiated with 7.5 MeV or 50 MeV energy electrons, using conventional electron accelerators.

Alloys strengthened by nanometer-sized Laves phases have been used as structural components working in corrosive environments at high temperatures owing to the favorable physical and chemical properties of Laves phases. However, due to the small sizes of Laves phases in alloys, their precise characterization cannot be realized efficiently by the existing methods. We previously found that under irradiation of a polished Zircaloy-4 alloy [Zr–1.50Sn–0.25Fe–0.15Cr (wt.%)] with a focused, low-energy (30 keV) electron beam, surface Zr atoms in the α-phase matrix, instead of the ones in nanometer-sized Zr(Fe, Cr)2 Laves phases, were able to undergo significant sputtering into vacuum in a field-emission scanning electron microscope (FE-SEM), resulting in the exposure of the Laves-phase nanoparticles (NPs). Based on this surprising physical phenomenon, here we successfully develop a methodology for performing statistical characterization of Laves-phase NPs in fully recrystallized Zircaloy-4 alloys as well as their partially recrystallized counterparts. By comparing the attributes of the Laves-phase NPs in both partially and fully recrystallized alloys, the conventional, tiny Ostwald ripening of the Laves phases was, for the first time, found to occur during the alloy recrystallization process. These understandings are likely to elucidate the universal mechanisms underlying the nucleation and growth of Laves-phase NPs in solid solutions.

The change in the positron annihilation lifetime (PAL) of vacancy clusters before and after electrolysis hydrogen charging was determined using PAL measurements in electron-irradiated F82H. The experimental change indicated 8 hydrogen atoms were trapped in vacancy clusters; whereas the theoretical calculation resulted in approximately 14 atoms. As the samples were left at room temperature for 5 min until the start of the PAL measurements, the de-trapping effect of hydrogen atoms was also considered; approximately 13 hydrogen atoms were captured at each vacancy cluster. The PAL decreased after annealing at 148 K, which could not be explained theoretically. Therefore, further experiments and discussions are needed to obtain a precise change in the PAL of vacancy clusters containing hydrogen atoms in F82H.

Kinetics of accumulation of oxygen–vacancy complexes, which is the dominant radiation-induced structural defect in the monocrystalline n-type Czochralski (Cz) silicon was studied experimentally and theoretically for silicon samples irradiated with electron beam pulses of various intensities and energies at 360 °C. The irradiation intensity was shown to have no effect on oxygen–vacancy complexes formation at temperatures when the complexes were unstable, but the complexes annealing efficiency revealed significant dependence on the electron beam intensity. In contrast, the electron beam energy affected the formation rate of vacancies themselves and their complexes with oxygen, but it did not influence annealing properties of oxygen–vacancy complexes. It occurred that the complexes generated in silicon at room temperature could be annealed at 360 °C much faster if irradiated with the electron beam during annealing. The results suggested an important role of radiation-induced ionization of a silicon crystal in transformation of oxygen–vacancy complexes into even more loaded complexes.

Converting a nonwetting surface to a highly wetting one, aided by ultraviolet radiation, is well explored. Here, in this work, we show just the reverse behavior of a copper-copper oxide nanocomposite surface where ultraviolet radiation turned the superhydrophilic surface to a superhydrophobic one. This observation is explained both experimentally and theoretically using first-principles density functional theory-based calculations considering the metal-oxygen (Cu-O) bond breaking and related change in surface chemistry. This observation has further been corroborated with electron irradiation on the same nanocomposite material. To the best of our knowledge, for the first time, we show that the radiation-induced breaking of the copper-oxygen bond makes the nanostructure surface energetically unfavorable for water adsorption.

Abstract Structural changes in silica glass, produced by electron irradiation, with electrons energies of 50 keV and doses of 5–80 mC/cm2 were studied by Raman spectroscopy in frequency ranges of 300–550 and of 700–1500 cm–1. It is shown that for irradiation doses less than 5 mC/cm2 the decrease of siloxane rings concentration in glass takes place. The further increase of dose results in the increase of siloxane rings concentration in glass network after irrsdiation. And for doses of more than 40 mC/cm2 the whole destruction of glass structure and its structural units takes place. The obtained results for silica glass were compared with similar results for crystalline quartz.

Erosion studies of polyimide, exposed to high energy electrons and atomic oxygen, is necessary in view of its application in space vehicles. Here we present the erosion studies and degradation characteristics of polyimide after its sequential exposure to 1 MeV pulsed electron beam from Microtron accelerator and ~12 eV oxygen ions from a plasma reactor in the laboratory. The fluence of electrons was varied from 5 × 1014 to 2.0 × 1015 electrons/cm2 and that of oxygen ions from ~5 × 1016 to 2 × 1017 ions cm−2. The post irradiated and virgin polyimide samples were characterized by gravimetric analysis and contact-angle measurements. The morphological and spectroscopic information were obtained with Scanning Electron Microscopy, Fourier Transform Infra-Red spectroscopy, and photo-absorption spectroscopy. The erosion yield, surface wettability and the surface roughness were seen to be much higher when exposed to both the radiations as compared to either of them, reflecting the synergetic effects.

The effects of 1 MeV electron irradiation in air at a fixed accumulated dose and dose rates of 393.8, 196.9, 78.8, and 39.4 Gy s-1 on a shape memory epoxy (SMEP) resin were studied. Under low-dose-rate irradiation, accelerated degradation of the shape memory performance was observed; specifically, the shape recovery ratio decreased exponentially with increasing irradiation time (that is, with decreasing dose rate). In addition, the glass transition temperature of the SMEP, as measured by dynamic mechanical analysis, decreased overall with decreasing dose rate. The dose rate effects of 1 MeV electron irradiation on the SMEP were confirmed by structural analysis using electron paramagnetic resonance (EPR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The EPR spectra showed that the concentration of free radicals increased exponentially with increasing irradiation time. Moreover, the FTIR spectra showed higher intensities of the peaks at 1660 and 1720 cm-1, which are attributed to stretching vibrations of amide C = O and ketone/acid C = O, at lower dose rates. The intensities of the IR peaks at 1660 and 1720 cm-1 increased exponentially with increasing irradiation time, and the relative intensity of the IR peak at 2926 cm-1 decreased exponentially with increasing irradiation time. The solid-state 13C nuclear magnetic resonance (NMR) spectra of the SMEP before and after 1 MeV electron irradiation at a dose of 1970 kGy and a dose rate of 78.8 Gy s-1 indicated damage to the CH2–N groups and aliphatic isopropanol segment. This result is consistent with the detection of nitrogenous free radicals, a phenoxy-type free radical, and several types of pyrolytic carbon radicals by EPR. During the subsequent propagation process, the free radicals produced at lower dose rates were more likely to react with oxygen, which was present at higher concentrations, and form the more destructive peroxy free radicals and oxidation products such as acids, amides, and ketones. The increase in peroxy free radicals at lower dose rates was thought to accelerate the degradation of the macroscopic performance of the SMEP.

Herein, we compared thermal desorption analysis (TDA) curves obtained by conducting experiments and simulations. In addition, we discussed the validation of our simulations and trapping sites of hydrogen atoms. In as-received F82H, when the samples contained solute atoms, grain boundaries, dislocations, and precipitates, the experimental curve corresponded to the simulated curve. In positron annihilation lifetime (PAL) measurements, di-vacancies were detected in the electron-irradiated F82H. When we changed the growth and the concentration of vacancy-type defects during temperature increase using the rate theory, the simulation results agreed with experiment results. In creep-ruptured Fe, only dislocations were detected by the PAL measurements. However, the existence of a type of defect, which was related to grain boundaries, must be assumed to fit the simulation curve to the experimental one. In the next step, the diffusion of hydrogen atoms on grain boundaries should be added to simulation program.

Electroplasticity in metals has been controversial since it is extremely hard to decouple the electron-induced heating in experiment. To illustrate the origin of this phenomenon, we applied density-functional theory (DFT) calculations to examine the response of injecting electrons and holes to face-centered-cubic metal, Rh, under finite shear deformation. We firstly examine the single crystal and find that single-crystal Rh can become more ductile/stronger with the electron/hole injection due to the less/more charge distribution between the sheared bonds cross the slip plane under deformation. Then the nanoscale twins are introduced to illustrate microstructure effect, and the simulation results indicated that nanoscale twins weaken the Rh, leading to a softening effect. With injected electron/hole, the nanotwinned structure displays the same more ductile/stronger effects as the single-crystal Rh. The origin of these effects arises from the weakened/enhanced bonding along twin boundaries. This study provides some insights on the origin of electroplasticity in metals.