Substantial defects are produced in Al2O3 by 4 MeV Au ion irradiation with a fluence of 4.4×10^15 cm^-2. Ruther- ford baekscattering spectrometry/channeling and cross-sectional transmission electron microscopy me...Substantial defects are produced in Al2O3 by 4 MeV Au ion irradiation with a fluence of 4.4×10^15 cm^-2. Ruther- ford baekscattering spectrometry/channeling and cross-sectional transmission electron microscopy methods are used to investigate the irradiation damage. The 190keV H ions with a fuence of 1×10^17 cm^-2 are used for implanting pristine and Au ion irradiated Al2O3 to explore the irradiation damage effects on the hydrogen retention in Al2O3. The time-of-flight secondary ion mass spectrometry method is used to obtaJn the single hydrogen depth profile and ions mass spectra （IMS）, in which we find that implanted hydrogens interacted with defects produced by Au ion irradiation. In IMS, we also obtain the hydrogen retention at a certain depth. Comparing the hydrogen retention in different Al2O3 samples, it is concluded that the irradiation damage improves the tritium permeation resistance property of Al2O3 under given conditions. This result means that Al2O3 may strengthen its property of reduc/ng tritium permeation under the harsh irradiation environment in fusion reactors.展开更多
Graphene and thin graphite films deposited on SiO2/Si are irradiated by swift heavy ions(209Bi, 9.5 Me V/u) with the fluences in a range of 1011ions/cm2–1012ions/cm2 at room temperature. Both pristine and irradiated ...Graphene and thin graphite films deposited on SiO2/Si are irradiated by swift heavy ions(209Bi, 9.5 Me V/u) with the fluences in a range of 1011ions/cm2–1012ions/cm2 at room temperature. Both pristine and irradiated samples are investigated by Raman spectroscopy. For pristine graphite films, the 'blue shift' of 2D bond and the 'red shift' of G bond with the decrease of thickness are found in the Raman spectra. For both irradiated graphene and thin graphite films, the disorder-induced D peak and D' peak are detected at the fluence above a threshold Φth. The thinner the film, the lower the Φthis. In this work, the graphite films thicker than 60 nm reveal defect free via the absence of a D bond signal under the swift heavy ion irradiation till the fluence of 2.6 × 1012ions/cm2. For graphite films thinner than 6 nm, the area ratios between D peak and G peak increase sharply with reducing film thickness. It concludes that it is much easier to induce defects in thinner films than in thicker ones by swift heavy ions. The intensities of the D peak and D' peak increase with increasing ion fluence, which predicts the continuous impacting of swift heavy ions can lead to the increasing of defects in samples. Different defect types are detected in graphite films of different thickness values. The main defect types are discussed via the various intensity ratios between the D peak and D' peak(HD/HD).展开更多
SRAM-based FPGA devices are irradiated by ^（60）Coγrays at various aose rates 10 investigate total dose effects and the evaluation method.The dependences of typical electrical parameters such as static power current...SRAM-based FPGA devices are irradiated by ^（60）Coγrays at various aose rates 10 investigate total dose effects and the evaluation method.The dependences of typical electrical parameters such as static power current, peak-peak value,and delay time on total dose are discussed.The experiment results show that the static power current of the devices reduces rapidly at room temperature（25℃） and high temperature（80℃） annealing after irradiation.When the device is irradiated at a low dose rate,the delay time and peak-peak value change unobviously with an increase in the accumulated dose.In contrast,the function parameters completely fail at 2.1 kGy（Si） when the dose rate increases to 0.71 Gy（Si）/s.展开更多
Because of their economy and applicability,high-power thyristor devices are widely used in the power supply systems for large fusion devices.When high-dose neutrons produced by deuterium–tritium(D–T)fusion reactions...Because of their economy and applicability,high-power thyristor devices are widely used in the power supply systems for large fusion devices.When high-dose neutrons produced by deuterium–tritium(D–T)fusion reactions are irradiated on a thyristor device for a long time,the electrical characteristics of the device change,which may eventually cause irreversible damage.In this study,with the thyristor switch of the commutation circuit in the quench protection system(QPS)of a fusion device as the study object,the relationship between the internal physical structure and external electrical parameters of the irradiated thyristor is established.Subsequently,a series of targeted thyristor physical simulations and neutron irradiation experiments are conducted to verify the accuracy of the theoretical analysis.In addition,the effect of irradiated thyristor electrical characteristic changes on the entire QPS is studied by accurate simulation,providing valuable guidelines for the maintenance and renovation of the QPS.展开更多
One dimensional Amosic-3 silicon carbide fiber reinforced silicon carbide matrix composites(SiCf/SiC minicomposites) prepared by chemical vapor infiltration were irradiated with 2.8 Me V proton ions. The ion fluences ...One dimensional Amosic-3 silicon carbide fiber reinforced silicon carbide matrix composites(SiCf/SiC minicomposites) prepared by chemical vapor infiltration were irradiated with 2.8 Me V proton ions. The ion fluences were 1.0 × 10^17 and 1.5 × 10^17cm^-2 at room temperature and 300℃, respectively. The microstructure and mechanical properties were investigated before and after proton irradiation. Raman spectra showed no evident change in Amosic-3 fibers regardless of irradiation temperature, which is confirmed by high resolution transmission electron microscopy observation. Pyrolytic carbon interphase showed slightly expansion after 300℃ irradiation, however, no microstructure changes were observed in SiC matrix. Moreover, it can be deduced that no irradiation induced changes in mechanical properties were observed after present proton irradiation.展开更多
Electron irradiation effects on phase stability of the E （Al18Cr2Mg3） phase have been investigated by high- angle annular dark-field scanning transmission electron microscopy and high-resolution transmission electro...Electron irradiation effects on phase stability of the E （Al18Cr2Mg3） phase have been investigated by high- angle annular dark-field scanning transmission electron microscopy and high-resolution transmission electron microscopy （HRTEM）. The in situ HRTEM observations show that the Ala8Cr2Mg3 particles with different thickness undergo amorphization and dissolution under 300 keV electron irradiation at 25 ℃. The results indicate that the intermetallic compound Al18Cr2Mg3 is unstable under electron irradiation, and structural changes mainly depend on the thickness of particles. Amorphization in the thick particles is caused by a combination of chemical disordering and an increase in point defect concentration. Dissolution after amorphization in the thin particles is attributed to the diffusion of point defect towards the Al matrix.展开更多
Low-energy proton irradiation effects on the optical properties and the molecular structure of phenyl-C_(61)-butyric acid methyl ester(PCBM)are studied in this work.The PCBM films are irradiated by 100-keV proton beam...Low-energy proton irradiation effects on the optical properties and the molecular structure of phenyl-C_(61)-butyric acid methyl ester(PCBM)are studied in this work.The PCBM films are irradiated by 100-keV proton beams with fluences of 5×10^(12)p/cm^(2),5×10^(13)p/cm^(2),and 5×10^(14)p/cm^(2),respectively.The photoluminescence(PL)peaks of the post-irradiated PCBM films show a progressive decrease in the peak intensity as the proton fluences increase,which can be attributed to the deep defect levels induced by proton irradiation.Additionally,a slight blue-shift in the PL spectrum is also observed at a proton fluence of 5×10^(14)p/cm^(2).The underlying mechanism can be traced back to the lift of the lowest unoccupied molecular orbital(LUMO)level,which is caused by the attachment of methoxy radicals on ortho position of the phenyl ring in the post-irradiated PCBM structure.This work is of significance in understanding the radiation hardness and the damage mechanism of the PCBM film in radiation environments,which is essential before it is put into practical application in space.展开更多
The microstructural responses of In_(0.32)Ga_(0.68)N and In_(0.9)Ga_(0.1)N films to 2.25 GeV Xe ion irradiation have been investigated using x-ray diffraction,Raman scattering,ion channeling and transmission electron ...The microstructural responses of In_(0.32)Ga_(0.68)N and In_(0.9)Ga_(0.1)N films to 2.25 GeV Xe ion irradiation have been investigated using x-ray diffraction,Raman scattering,ion channeling and transmission electron microscopy.It was found that the In-rich In_(0.9)Ga_(0.1)N is more susceptible to irradiation than the Ga-rich In_(0.32)Ga_(0.68)N.Xe ion irradiation with a fluence of 7×10^(11)ions·cm^(-2)leads to little damage in In_(0.32)Ga_(0.68)N but an obvious lattice expansion in In_(0.9)Ga_(0.1)N.The level of lattice disorder in In_(0.9)Ga_(0.1)N increases after irradiation,due to the huge electronic energy deposition of the incident Xe ions.However,no Xe ion tracks were observed to be formed,which is attributed to the very high velocity of 2.25 Ge V Xe ions.Point defects and/or small defect clusters are probably the dominant defect type in Xe-irradiated In_(0.9)Ga_(0.1)N.展开更多
The effect of irradiation on the strain sensitivity coefficient of strain sensing fiber Bragg gratings （FBGs） has been investigated through experiments. FBGs were fabricated in single mode fibers with 3 tool% Ge-con...The effect of irradiation on the strain sensitivity coefficient of strain sensing fiber Bragg gratings （FBGs） has been investigated through experiments. FBGs were fabricated in single mode fibers with 3 tool% Ge-concentration in the core and with a H2-1oading treatment. In experiments, the FBGs were subjected to y-radiation exposures using a Co6~ source at a dose-rate of 25 Gy/min up to a total dose of 10.5 kGy. The GeO defect in fiber absorbs photons to form a GeE＇ defect; the interaction with H2 is a probable reason for the y-radiation sensitivity of gratings written in hydrogen loaded fibres, The effect mechanism of radiation on the strain sensitivity coefficient is similar to that of radiation on the temperature sensitivity coefficient. Radiation affects the effective index neff, which results in the change of the thermo-optic coefficient and the strain-optic coefficient. Irradiation can change the strain sensitivity coefficient of FBGs by 1.48%-2.71%, as well as changing the Bragg wavelength shift （BWS） by 22 pm-25 pm under a total dose of 10.5 kGy. Our research demonstrates that the effect of irradiation on the strain sensitivity coefficient of FBG is small and that strain sensing FBGs can work well in the radiation environment.展开更多
The effects of annealing and irradiation on the evolution of Cu clusters in a-Fe are investigated using object kinetic Monte Carlo simulations.In our model,vacancies act as carriers for chemical species via thermally ...The effects of annealing and irradiation on the evolution of Cu clusters in a-Fe are investigated using object kinetic Monte Carlo simulations.In our model,vacancies act as carriers for chemical species via thermally activated diffusion jumps,thus playing an important role in solute diffusion.At the end of the Cu cluster evolution,the simulations of the average radius and number density of the clusters are consistent with the experimental data,which indicates that the proposed simulation model is applicable and effective.For the simulation of the annealing process,it is found that the evolution of the cluster size roughly follows the 1/2 time power law with the increase in radius during the growth phase and the 1/3 time power law during the coarsening phase.In addition,the main difference between neutron and ion irradiation is the growth and evolution process of the copper-vacancy clusters.The aggregation of vacancy clusters under ion irradiation suppresses the migration and coarsening of the clusters,which ultimately leads to a smaller average radius of the copper clusters.Our proposed simulation model can supplement experimental analyses and provide a detailed evolution mechanism of vacancy-enhanced precipitation,thereby providing a foundation for other elemental precipitation research.展开更多
Ultrahigh-molecular-weight polyethylene(UtlMWPE) has been irradiated (0-40 Mrad) with a Co^(60) source at room temperature under vacuum. Their crystallinity has been investigated by DSC and SAXS A significant increase...Ultrahigh-molecular-weight polyethylene(UtlMWPE) has been irradiated (0-40 Mrad) with a Co^(60) source at room temperature under vacuum. Their crystallinity has been investigated by DSC and SAXS A significant increase of heat of fusion can be seen at low irradiation doses, which is attributed to crystallization caused by chain scission during the process of irradiation. It is also observed that thickness of lamellae changes with irradiation dose. Young's modulus has been improved significantly after irradiation at low doses.展开更多
The hardening of the buried oxide （BOX） layer of separation by implanted oxygen （SIMOX） silicon-on-insulator （SOI） wafers against total-dose irradiation was investigated by implanting ions into the BOX layers. T...The hardening of the buried oxide （BOX） layer of separation by implanted oxygen （SIMOX） silicon-on-insulator （SOI） wafers against total-dose irradiation was investigated by implanting ions into the BOX layers. The tolerance to total-dose irradiation of the BOX layers was characterized by the comparison of the transfer characteristics of SOI NMOS transistors before and after irradiation to a total dose of 2.7 Mrad（SiO2）. The experimental results show that the implantation of silicon ions into the BOX layer can improve the tolerance of the BOX layers to total-dose irradiation. The investigation of the mechanism of the improvement suggests that the deep electron traps introduced by silicon implantation play an important role in the remarkable improvement in radiation hardness of SIMOX SOI wafers.展开更多
In this paper,a crystal plasticity model considering the irradiation effect based on the thermal activation theory is established.The evolutions of screw dislocations,edge dislocations,and stacking fault tetrahedrals(...In this paper,a crystal plasticity model considering the irradiation effect based on the thermal activation theory is established.The evolutions of screw dislocations,edge dislocations,and stacking fault tetrahedrals(SFTs)(induced by irradiation)are included into the model.The interactions between dislocations and irradiation-induced SFTs are also considered.The constitutive model is numerically implemented on the ABAQUS platform through UMAT subroutine and applied to study the irradiation effect on the mechanical behavior of pure copper.The mechanical properties of single and polycrystalline copper are studied,and the simulation results show that the constitutive model can properly predict the mechanical behavior of irradiated pure copper.Especially for polycrystalline copper,the simulation results are in good agreement with the experimental data.展开更多
Recently, water treatment by ionizing radiation has gained increasing attention as a powerful technology for the destruction of refractory pollutants. 2-Mercaptobenzothiazole（MBT） is known as a widespread, toxic and...Recently, water treatment by ionizing radiation has gained increasing attention as a powerful technology for the destruction of refractory pollutants. 2-Mercaptobenzothiazole（MBT） is known as a widespread, toxic and poorly biodegradable pollutant. This paper studied the gamma irradiation of aqueous solutions of MBT. Moreover, the effect of the addition of persulfate（S2O82-） on the radiolytic destruction of MBT was investigated. The main transformation products of the studied compound were detected and the sequence of occurrence of the products was described. The change of biodegradability of MBT solution was also observed. The main results obtained in this study indicated that gamma radiation was effective for removing MBT in aqueous solution. Persulfate addition, which induced the formation of reactive sulfate radicals（SO4-U）, greatly enhanced the degradation of MBT. Benzothiazole was identified as the first radiation product, followed by 2-hydroxybenzothiazole. Decomposition of MBT started with the oxidation of –SH groups to sulfate ions. Possible pathways for MBT decomposition by gamma irradiation were proposed. The BOD/COD ratios of MBT samples were increased after radiation,indicating the improvement of biodegradability and reduction of toxicity.展开更多
The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors （nMOSFETs） is investigated. Experimental results show that hot-carrier degradati...The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors （nMOSFETs） is investigated. Experimental results show that hot-carrier degradations on ir- radiated narrow channel nMOSFETs are greater than those without irradiation. The reason is attributed to radiation-induced charge trapping in shallow trench isolation （STI）. The electric field in the pinch-off region of the nMOSFET is enhanced by radiation-induced charge trapping in STI, resulting in a more severe hot-carrier effect.展开更多
Most irradiation studies in the hydrogen bonded ferroelectrics have been concentrated on the transient defects induced by ionising radiation, such as ultraviolet （UV） light, where the defects are closely related to ...Most irradiation studies in the hydrogen bonded ferroelectrics have been concentrated on the transient defects induced by ionising radiation, such as ultraviolet （UV） light, where the defects are closely related to the optical properties. But heavy ion beam irradiation effects have rarely been studied. The structural, optical, and non-linear optical properties of the doped crystals were analyzed with the characterization studies, such as powder XRD, UV-Visible and second harmonic generation （SHG） measurements, respectively. The results for doped KDP crystal were compared with the results of the pure KDP crystals. The experiment results showed that Li^3＋ irradiation leads to the development of a well-defined surface H peak in dye doped KDP crystals. The stability of KDP single crystal was improved by doping organic dyes. The nano-islands of dye in KDP were likely to be dissolved and enhance the non-linear optical properties of these materials.展开更多
Y1.6Ca1.4V 0.45Sn0.5Fe4.05O12 is irradiated by 0.56 GeV carbon ion. The irradiation effect is investigated by Mossbauer spectroscopy. The irradiation results in an isotropic distribution of the hyperfine magnetic fiel...Y1.6Ca1.4V 0.45Sn0.5Fe4.05O12 is irradiated by 0.56 GeV carbon ion. The irradiation effect is investigated by Mossbauer spectroscopy. The irradiation results in an isotropic distribution of the hyperfine magnetic field. The hyperfine magnetic fields decrease after the irradiation due to the change of supertransferred field. After the irradiation, the chain Fe(a)-oxygen-Fe(d) become longer and it leads to decrease of the supertransferred field.展开更多
Room temperature irradiation effect of GaAs compound semiconductor by 100 keV Ar+ ions has been systematically studied by means of transmission electron microscopy. The dose dependenceoof the Ar+ ion irradiation and r...Room temperature irradiation effect of GaAs compound semiconductor by 100 keV Ar+ ions has been systematically studied by means of transmission electron microscopy. The dose dependenceoof the Ar+ ion irradiation and room temperature annealing effects have been investigated. The experimental results show that the structure of GaAs transforms from perfect crystalline through weakly and severely damaged crystalline to amorphous states with the increase of the irradiation dose and the damaged states are changed during room temperature annealing.展开更多
This paper presents numerous physical characteristics of Ca, V, Sn doped yttrium iron garnet (CaVSn:YIG) irradiated with 0.56GeV carbon ions delivered by the Heavy Ion Research Facility of Lanzhou (HIRFL). The reason...This paper presents numerous physical characteristics of Ca, V, Sn doped yttrium iron garnet (CaVSn:YIG) irradiated with 0.56GeV carbon ions delivered by the Heavy Ion Research Facility of Lanzhou (HIRFL). The reason for change of the magnetic properties of the samples induced by energetic carbon ions bombardment is discussed. By comparison of this results with the irradiation effects of YIG induced by energetic argon, krypton and xenon obtained on the GANIL, Caen,France, it is concluded that the irradiation effect of 0.56 GeV C6+ on CaVSn.YIG arises from the electronic energy losses.展开更多
A finite-strain homogenization creep model for composite fuels under irradiation conditions is developed and verified,with the irradiation creep strains of the fuel particles and matrix correlated to the macroscale cr...A finite-strain homogenization creep model for composite fuels under irradiation conditions is developed and verified,with the irradiation creep strains of the fuel particles and matrix correlated to the macroscale creep responses,excluding the contributions of volumetric strain induced by the irradiation swelling deformations of fuel particles.A finite element(FE)modeling method for uniaxial tensile creep tests is established with the irradiation effects of nuclear materials taken into account.The proposed models and simulation strategy are numerically implemented to a kind of composite nuclear fuel,and the predicted mesoscale creep behaviors and the macroscale creep responses are investigated.The research results indicate that:(1)the macroscale creep responses and the mesoscale stress and strain fields are all greatly affected by the irradiation swelling of fuel particles,owing to the strengthened mechanical interactions between the fuel particles and the matrix.(2)The effective creep rates for a certain case are approximately two constants before and after the critical fission density,which results from the accelerated fission gas swelling after fuel grain recrystallization,and the effects of macroscale tensile stress will be more enhanced at higher temperatures.(3)The macroscale creep contributions from the fuel particles and matrix depend mainly on the current volume fractions varying with fission density.(4)As a function of the macroscale stress,temperature,initial particle volume fraction and particle fission rate,a multi-variable mathematical model for effective creep rates is fitted out for the considered composite fuels,which matches well with the FE predictions.This study supplies important theoretical models and research methods for the multi-scale creep behaviors of various composite fuels and provides a basis for simulation of the thermal–mechanical behavior in related composite fuel elements and assemblies.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 91426304 and 91226202the National Magnetic Confinement Fusion Energy Research Project under Grant No 2015GB113000
文摘Substantial defects are produced in Al2O3 by 4 MeV Au ion irradiation with a fluence of 4.4×10^15 cm^-2. Ruther- ford baekscattering spectrometry/channeling and cross-sectional transmission electron microscopy methods are used to investigate the irradiation damage. The 190keV H ions with a fuence of 1×10^17 cm^-2 are used for implanting pristine and Au ion irradiated Al2O3 to explore the irradiation damage effects on the hydrogen retention in Al2O3. The time-of-flight secondary ion mass spectrometry method is used to obtaJn the single hydrogen depth profile and ions mass spectra （IMS）, in which we find that implanted hydrogens interacted with defects produced by Au ion irradiation. In IMS, we also obtain the hydrogen retention at a certain depth. Comparing the hydrogen retention in different Al2O3 samples, it is concluded that the irradiation damage improves the tritium permeation resistance property of Al2O3 under given conditions. This result means that Al2O3 may strengthen its property of reduc/ng tritium permeation under the harsh irradiation environment in fusion reactors.
基金supported by the National Natural Science Foundation of China(Grant Nos.11179003,10975164,10805062,11005134,and 11275237)
文摘Graphene and thin graphite films deposited on SiO2/Si are irradiated by swift heavy ions(209Bi, 9.5 Me V/u) with the fluences in a range of 1011ions/cm2–1012ions/cm2 at room temperature. Both pristine and irradiated samples are investigated by Raman spectroscopy. For pristine graphite films, the 'blue shift' of 2D bond and the 'red shift' of G bond with the decrease of thickness are found in the Raman spectra. For both irradiated graphene and thin graphite films, the disorder-induced D peak and D' peak are detected at the fluence above a threshold Φth. The thinner the film, the lower the Φthis. In this work, the graphite films thicker than 60 nm reveal defect free via the absence of a D bond signal under the swift heavy ion irradiation till the fluence of 2.6 × 1012ions/cm2. For graphite films thinner than 6 nm, the area ratios between D peak and G peak increase sharply with reducing film thickness. It concludes that it is much easier to induce defects in thinner films than in thicker ones by swift heavy ions. The intensities of the D peak and D' peak increase with increasing ion fluence, which predicts the continuous impacting of swift heavy ions can lead to the increasing of defects in samples. Different defect types are detected in graphite films of different thickness values. The main defect types are discussed via the various intensity ratios between the D peak and D' peak(HD/HD).
文摘SRAM-based FPGA devices are irradiated by ^（60）Coγrays at various aose rates 10 investigate total dose effects and the evaluation method.The dependences of typical electrical parameters such as static power current, peak-peak value,and delay time on total dose are discussed.The experiment results show that the static power current of the devices reduces rapidly at room temperature（25℃） and high temperature（80℃） annealing after irradiation.When the device is irradiated at a low dose rate,the delay time and peak-peak value change unobviously with an increase in the accumulated dose.In contrast,the function parameters completely fail at 2.1 kGy（Si） when the dose rate increases to 0.71 Gy（Si）/s.
基金supported by the Fundamental Research Funds for the Central University(No.JZ2023HGTA0182)Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228)。
文摘Because of their economy and applicability,high-power thyristor devices are widely used in the power supply systems for large fusion devices.When high-dose neutrons produced by deuterium–tritium(D–T)fusion reactions are irradiated on a thyristor device for a long time,the electrical characteristics of the device change,which may eventually cause irreversible damage.In this study,with the thyristor switch of the commutation circuit in the quench protection system(QPS)of a fusion device as the study object,the relationship between the internal physical structure and external electrical parameters of the irradiated thyristor is established.Subsequently,a series of targeted thyristor physical simulations and neutron irradiation experiments are conducted to verify the accuracy of the theoretical analysis.In addition,the effect of irradiated thyristor electrical characteristic changes on the entire QPS is studied by accurate simulation,providing valuable guidelines for the maintenance and renovation of the QPS.
基金supported by the National Natural Science Foundation of China (No.11575143)the Creative Research Foundation of Science and Technology on the Thermostructural Composite Material Laboratory (No.6142911030411)+1 种基金the Fundamental Research Funds for the Central Universities (No. 3102019TS0403)Science and Technology on Combustion, Internal Flow and Thermo-Structure Laboratory (No.6142701190302)
文摘One dimensional Amosic-3 silicon carbide fiber reinforced silicon carbide matrix composites(SiCf/SiC minicomposites) prepared by chemical vapor infiltration were irradiated with 2.8 Me V proton ions. The ion fluences were 1.0 × 10^17 and 1.5 × 10^17cm^-2 at room temperature and 300℃, respectively. The microstructure and mechanical properties were investigated before and after proton irradiation. Raman spectra showed no evident change in Amosic-3 fibers regardless of irradiation temperature, which is confirmed by high resolution transmission electron microscopy observation. Pyrolytic carbon interphase showed slightly expansion after 300℃ irradiation, however, no microstructure changes were observed in SiC matrix. Moreover, it can be deduced that no irradiation induced changes in mechanical properties were observed after present proton irradiation.
基金financially supported by the 111 Project (No. B08040) of ChinaNational Natural Science Foundation of China (No. 51071125)
文摘Electron irradiation effects on phase stability of the E （Al18Cr2Mg3） phase have been investigated by high- angle annular dark-field scanning transmission electron microscopy and high-resolution transmission electron microscopy （HRTEM）. The in situ HRTEM observations show that the Ala8Cr2Mg3 particles with different thickness undergo amorphization and dissolution under 300 keV electron irradiation at 25 ℃. The results indicate that the intermetallic compound Al18Cr2Mg3 is unstable under electron irradiation, and structural changes mainly depend on the thickness of particles. Amorphization in the thick particles is caused by a combination of chemical disordering and an increase in point defect concentration. Dissolution after amorphization in the thin particles is attributed to the diffusion of point defect towards the Al matrix.
基金Project supported by the Youth Innovation Promotion Association,Chinese Academy of Sciencesthe National Natural Science Foundation of China(Grant No.61874135)the Foundation of Frontier Science of the Chinese Academy of Sciences(Grant No.ZDBS-LY-JSC015)。
文摘Low-energy proton irradiation effects on the optical properties and the molecular structure of phenyl-C_(61)-butyric acid methyl ester(PCBM)are studied in this work.The PCBM films are irradiated by 100-keV proton beams with fluences of 5×10^(12)p/cm^(2),5×10^(13)p/cm^(2),and 5×10^(14)p/cm^(2),respectively.The photoluminescence(PL)peaks of the post-irradiated PCBM films show a progressive decrease in the peak intensity as the proton fluences increase,which can be attributed to the deep defect levels induced by proton irradiation.Additionally,a slight blue-shift in the PL spectrum is also observed at a proton fluence of 5×10^(14)p/cm^(2).The underlying mechanism can be traced back to the lift of the lowest unoccupied molecular orbital(LUMO)level,which is caused by the attachment of methoxy radicals on ortho position of the phenyl ring in the post-irradiated PCBM structure.This work is of significance in understanding the radiation hardness and the damage mechanism of the PCBM film in radiation environments,which is essential before it is put into practical application in space.
基金Project supported by the National Natural Science Foundation of China(Grant No.11875154)State Key Laboratory of Intense Pulsed Radiation Simulation and Effect(Grant No.SKLIPR2014)。
文摘The microstructural responses of In_(0.32)Ga_(0.68)N and In_(0.9)Ga_(0.1)N films to 2.25 GeV Xe ion irradiation have been investigated using x-ray diffraction,Raman scattering,ion channeling and transmission electron microscopy.It was found that the In-rich In_(0.9)Ga_(0.1)N is more susceptible to irradiation than the Ga-rich In_(0.32)Ga_(0.68)N.Xe ion irradiation with a fluence of 7×10^(11)ions·cm^(-2)leads to little damage in In_(0.32)Ga_(0.68)N but an obvious lattice expansion in In_(0.9)Ga_(0.1)N.The level of lattice disorder in In_(0.9)Ga_(0.1)N increases after irradiation,due to the huge electronic energy deposition of the incident Xe ions.However,no Xe ion tracks were observed to be formed,which is attributed to the very high velocity of 2.25 Ge V Xe ions.Point defects and/or small defect clusters are probably the dominant defect type in Xe-irradiated In_(0.9)Ga_(0.1)N.
基金Project supported by the National Natural Science Foundation of China(Grant No.61007040)
文摘The effect of irradiation on the strain sensitivity coefficient of strain sensing fiber Bragg gratings （FBGs） has been investigated through experiments. FBGs were fabricated in single mode fibers with 3 tool% Ge-concentration in the core and with a H2-1oading treatment. In experiments, the FBGs were subjected to y-radiation exposures using a Co6~ source at a dose-rate of 25 Gy/min up to a total dose of 10.5 kGy. The GeO defect in fiber absorbs photons to form a GeE＇ defect; the interaction with H2 is a probable reason for the y-radiation sensitivity of gratings written in hydrogen loaded fibres, The effect mechanism of radiation on the strain sensitivity coefficient is similar to that of radiation on the temperature sensitivity coefficient. Radiation affects the effective index neff, which results in the change of the thermo-optic coefficient and the strain-optic coefficient. Irradiation can change the strain sensitivity coefficient of FBGs by 1.48%-2.71%, as well as changing the Bragg wavelength shift （BWS） by 22 pm-25 pm under a total dose of 10.5 kGy. Our research demonstrates that the effect of irradiation on the strain sensitivity coefficient of FBG is small and that strain sensing FBGs can work well in the radiation environment.
基金supported by the National Natural Science Foundation of China (Nos.11975135 and 12005017)China Postdoctoral Science Foundation (No.2021M701829)
文摘The effects of annealing and irradiation on the evolution of Cu clusters in a-Fe are investigated using object kinetic Monte Carlo simulations.In our model,vacancies act as carriers for chemical species via thermally activated diffusion jumps,thus playing an important role in solute diffusion.At the end of the Cu cluster evolution,the simulations of the average radius and number density of the clusters are consistent with the experimental data,which indicates that the proposed simulation model is applicable and effective.For the simulation of the annealing process,it is found that the evolution of the cluster size roughly follows the 1/2 time power law with the increase in radius during the growth phase and the 1/3 time power law during the coarsening phase.In addition,the main difference between neutron and ion irradiation is the growth and evolution process of the copper-vacancy clusters.The aggregation of vacancy clusters under ion irradiation suppresses the migration and coarsening of the clusters,which ultimately leads to a smaller average radius of the copper clusters.Our proposed simulation model can supplement experimental analyses and provide a detailed evolution mechanism of vacancy-enhanced precipitation,thereby providing a foundation for other elemental precipitation research.
文摘Ultrahigh-molecular-weight polyethylene(UtlMWPE) has been irradiated (0-40 Mrad) with a Co^(60) source at room temperature under vacuum. Their crystallinity has been investigated by DSC and SAXS A significant increase of heat of fusion can be seen at low irradiation doses, which is attributed to crystallization caused by chain scission during the process of irradiation. It is also observed that thickness of lamellae changes with irradiation dose. Young's modulus has been improved significantly after irradiation at low doses.
基金Project supported by the National Fund for Distinguished Young Scholars （Grant No 59925205）, the Basic Research Program of Shanghai （Grant No 02DJ14069）, and the National Natural Science Foundation of China （Grant No 10305018）.
文摘The hardening of the buried oxide （BOX） layer of separation by implanted oxygen （SIMOX） silicon-on-insulator （SOI） wafers against total-dose irradiation was investigated by implanting ions into the BOX layers. The tolerance to total-dose irradiation of the BOX layers was characterized by the comparison of the transfer characteristics of SOI NMOS transistors before and after irradiation to a total dose of 2.7 Mrad（SiO2）. The experimental results show that the implantation of silicon ions into the BOX layer can improve the tolerance of the BOX layers to total-dose irradiation. The investigation of the mechanism of the improvement suggests that the deep electron traps introduced by silicon implantation play an important role in the remarkable improvement in radiation hardness of SIMOX SOI wafers.
基金The support of the National Natural Science Foundation of China(NSFC)under Grant No.11202114Beijing Higher Education Young Elite Teacher Project under Grant No.YETP0156Tsinghua University Initiative Scientific Research Program under Grant No.2019Z08QCX06 are gratefully acknowledged。
文摘In this paper,a crystal plasticity model considering the irradiation effect based on the thermal activation theory is established.The evolutions of screw dislocations,edge dislocations,and stacking fault tetrahedrals(SFTs)(induced by irradiation)are included into the model.The interactions between dislocations and irradiation-induced SFTs are also considered.The constitutive model is numerically implemented on the ABAQUS platform through UMAT subroutine and applied to study the irradiation effect on the mechanical behavior of pure copper.The mechanical properties of single and polycrystalline copper are studied,and the simulation results show that the constitutive model can properly predict the mechanical behavior of irradiated pure copper.Especially for polycrystalline copper,the simulation results are in good agreement with the experimental data.
基金the National Hi-Tech Research and Development Program(863)of China(No.2009AA063905)supported by the Chinese Ministry of Science and Technology and the Independent Research Project(No.20101081929)supported by Tsinghua University
文摘Recently, water treatment by ionizing radiation has gained increasing attention as a powerful technology for the destruction of refractory pollutants. 2-Mercaptobenzothiazole（MBT） is known as a widespread, toxic and poorly biodegradable pollutant. This paper studied the gamma irradiation of aqueous solutions of MBT. Moreover, the effect of the addition of persulfate（S2O82-） on the radiolytic destruction of MBT was investigated. The main transformation products of the studied compound were detected and the sequence of occurrence of the products was described. The change of biodegradability of MBT solution was also observed. The main results obtained in this study indicated that gamma radiation was effective for removing MBT in aqueous solution. Persulfate addition, which induced the formation of reactive sulfate radicals（SO4-U）, greatly enhanced the degradation of MBT. Benzothiazole was identified as the first radiation product, followed by 2-hydroxybenzothiazole. Decomposition of MBT started with the oxidation of –SH groups to sulfate ions. Possible pathways for MBT decomposition by gamma irradiation were proposed. The BOD/COD ratios of MBT samples were increased after radiation,indicating the improvement of biodegradability and reduction of toxicity.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11475255,U1532261 and 11505282
文摘The influence of total dose irradiation on hot-carrier reliability of 65 nm n-type metal-oxide-semiconductor field- effect transistors （nMOSFETs） is investigated. Experimental results show that hot-carrier degradations on ir- radiated narrow channel nMOSFETs are greater than those without irradiation. The reason is attributed to radiation-induced charge trapping in shallow trench isolation （STI）. The electric field in the pinch-off region of the nMOSFET is enhanced by radiation-induced charge trapping in STI, resulting in a more severe hot-carrier effect.
文摘Most irradiation studies in the hydrogen bonded ferroelectrics have been concentrated on the transient defects induced by ionising radiation, such as ultraviolet （UV） light, where the defects are closely related to the optical properties. But heavy ion beam irradiation effects have rarely been studied. The structural, optical, and non-linear optical properties of the doped crystals were analyzed with the characterization studies, such as powder XRD, UV-Visible and second harmonic generation （SHG） measurements, respectively. The results for doped KDP crystal were compared with the results of the pure KDP crystals. The experiment results showed that Li^3＋ irradiation leads to the development of a well-defined surface H peak in dye doped KDP crystals. The stability of KDP single crystal was improved by doping organic dyes. The nano-islands of dye in KDP were likely to be dissolved and enhance the non-linear optical properties of these materials.
文摘Y1.6Ca1.4V 0.45Sn0.5Fe4.05O12 is irradiated by 0.56 GeV carbon ion. The irradiation effect is investigated by Mossbauer spectroscopy. The irradiation results in an isotropic distribution of the hyperfine magnetic field. The hyperfine magnetic fields decrease after the irradiation due to the change of supertransferred field. After the irradiation, the chain Fe(a)-oxygen-Fe(d) become longer and it leads to decrease of the supertransferred field.
文摘Room temperature irradiation effect of GaAs compound semiconductor by 100 keV Ar+ ions has been systematically studied by means of transmission electron microscopy. The dose dependenceoof the Ar+ ion irradiation and room temperature annealing effects have been investigated. The experimental results show that the structure of GaAs transforms from perfect crystalline through weakly and severely damaged crystalline to amorphous states with the increase of the irradiation dose and the damaged states are changed during room temperature annealing.
文摘This paper presents numerous physical characteristics of Ca, V, Sn doped yttrium iron garnet (CaVSn:YIG) irradiated with 0.56GeV carbon ions delivered by the Heavy Ion Research Facility of Lanzhou (HIRFL). The reason for change of the magnetic properties of the samples induced by energetic carbon ions bombardment is discussed. By comparison of this results with the irradiation effects of YIG induced by energetic argon, krypton and xenon obtained on the GANIL, Caen,France, it is concluded that the irradiation effect of 0.56 GeV C6+ on CaVSn.YIG arises from the electronic energy losses.
基金supports from the National Natural Science Foundation of China (Nos.12132005,12102094 and 12135008)the Shanghai Sailing Program (21YF1402200)the foundation from the Science and Technology on Reactor System Design Technology Laboratory.
文摘A finite-strain homogenization creep model for composite fuels under irradiation conditions is developed and verified,with the irradiation creep strains of the fuel particles and matrix correlated to the macroscale creep responses,excluding the contributions of volumetric strain induced by the irradiation swelling deformations of fuel particles.A finite element(FE)modeling method for uniaxial tensile creep tests is established with the irradiation effects of nuclear materials taken into account.The proposed models and simulation strategy are numerically implemented to a kind of composite nuclear fuel,and the predicted mesoscale creep behaviors and the macroscale creep responses are investigated.The research results indicate that:(1)the macroscale creep responses and the mesoscale stress and strain fields are all greatly affected by the irradiation swelling of fuel particles,owing to the strengthened mechanical interactions between the fuel particles and the matrix.(2)The effective creep rates for a certain case are approximately two constants before and after the critical fission density,which results from the accelerated fission gas swelling after fuel grain recrystallization,and the effects of macroscale tensile stress will be more enhanced at higher temperatures.(3)The macroscale creep contributions from the fuel particles and matrix depend mainly on the current volume fractions varying with fission density.(4)As a function of the macroscale stress,temperature,initial particle volume fraction and particle fission rate,a multi-variable mathematical model for effective creep rates is fitted out for the considered composite fuels,which matches well with the FE predictions.This study supplies important theoretical models and research methods for the multi-scale creep behaviors of various composite fuels and provides a basis for simulation of the thermal–mechanical behavior in related composite fuel elements and assemblies.
