HIGH-ENERGY PROTON IRRADIATION EFFECTS ON GaAs/Ge SPACE SOLAR CELLS

This paper reports the high-energy proton irradiation effects on GaAs/Ge space solar cells. The solar cells were irradiated by protons with energy of 5-20 MeV at fluence ranging from 1×109 to 7×1013 cm-2, and then their electric parameters were measured at AM0. It was shown that the Isc, Voc and Pmax decrease as the proton energy increasing, and the degradation is relative to proton irradiation-induced defect with a level of Ec-0.41 eV in irradiated GaAs/Ge cells.

Toxicological Evaluation of Chicken-Breast Meat with High-Dose Irradiation

In this paper, toxicity and safety of high-dose irradiated chicken-breast meat were evaluated. For assays of acute toxicity, genetic toxicity, and sub-chronic toxicity, ames test, mice bone marrow erythrocyte micronucleus, and mice sperm abnormality were performed. The results showed that, in the acute oral toxicity tests, median lethal dose （more than 10 000 mg kg-~） in male and female ICR mice showed no toxicological signs. For subacute 30-d oral toxicology of irradiated chicken-breast meat with dose of 10, 15 and 25 kGy in both male and female SD rats, no noticeable toxicological effects were observed. It is concluded that chicken-breast meat with high-dose irradiation has no acute toxicity and no genotoxicity, nor harmful effects on the animal body at the tested dosage range. Therefore, high-dose irradiated chicken-breast meat is safe for pet consumption.

Neutron irradiation effects on AlGaN/GaN high electron mobility transistors

A1GaN/GaN high electron mobility transistors （HEMTs） were exposed to 1 MeV neutron irradiation at a neutron ftuence of 1 × 10^15 cm-2. The dc characteristics of the devices, such as the drain saturation current and the maximum transconductance, decreased after neutron irradiation. The gate leakage currents increased obviously after neutron irradiation. However, the rf characteristics, such as the cut-off frequency and the maximum frequency, were hardly affected by neutron irradiation. The A1GaN/GaN heterojunctions have been employed for the better understanding of the degradation mechanism. It is shown in the Hall measurements and capacitance voltage tests that the mobility and concentration of two-dimensional electron gas （2DEG） decreased after neutron irradiation. Tbere was no evidence of the full-width at half-maximum of X-ray diffraction （XRD） rocking curve changing after irradiation, so the dislocation was not influenced by neutron irradiation. It is concluded that the point defects induced in A1GaN and GaN by neutron irradiation are the dominant mechanisms responsible for performance degradations of A1GaN/GaN HEMT devices.

Effect of aging treatment on irradiation-induced segregation of high Mn-Cr steel

To investigate the effect of aging treatment on irradiation-induced segregation of high Mn-Cr steel, specimens for electron-beam irradiation were prepared from the high Mn-Cr austenitic steel which was solution treated at 1 373 K for 1 h and aging treated at 573 K for 1 000 h, respectively. The electron-beam irradiation was performed at 573 K up to doses of 5.4 dpa in a 1 250 kV HVEM and irradiation-induced segregation analyses were carried out by an EDX in a 200 kV FE-TEM. The results show that void formation is not observed in both solution treated and aging treated ones. The amount of Cr segregation at the grain boundary decreases in the aged one; however, that of Mn is not changed in solution treated one.

Research on Irradiation Electric Field for Charged Particles Beam with High Energy

Irradiation protection of the nonlinear optical devices used in the spacecraft and next generation active laser system must be solved. The first problem was to find the irradiation damage mechanism of the nonlinear materials. In this paper the irradiation electronic field originating from high speed charged particle beams was discussed. The calculating model of the electronic field, based on the relativistic mechanics and electro-magnetic theory, was founded. The common characters of the irradiation electronic field were predicted and the fields of α ray and β ray were calculated by means of our model. The simulating results showed that the intensity of the electric field increased with the energy or the intensity of the beam. The results also showed that the field change trend of α ray and β ray was similar, but the field value was quite different. When the beam intensity I = 100 μA and the beam energy εm = 500 Mev, the electronic field values were about 3.5 × 107 v/m for α ray and 2.4 × 1011 v/m for β ray.

Meso-scale Discovery Assay Detects the Changes of Plasma Cytokine Levels in Mice after Low or High LET Ionizing Irradiation

Objective To obtain precise data on the changes in the levels of 29 cytokines in mice after high or low linear energy transfer(LET)irradiation and to develop an accurate model of radiation exposure based on the cytokine levels after irradiation.Methods Plasma samples harvested from mice at different time points after carbon-ion or X-ray irradiation were analyzed using meso-scale discovery(MSD),a high-throughput and sensitive electrochemiluminescence measurement technique.Dose estimation equations were set up using multiple linear regression analysis.Results The relative levels of IL-6 at 1 h,IL-5 and IL-6 at 24 h,and IL-5,IL-6 and IL-15 at 7 d after irradiation with two intensities increased dose-dependently.The minimum measured levels of IL-5,IL-6 and IL-15 were up to 4.0076 pg/mL,16.4538 pg/mL and 0.4150 pg/mL,respectively.In addition,dose estimation models were established and verified.Conclusions The MSD assay can provide more accurate data regarding the changes in the levels of the cytokines IL-5,IL-6 and IL-15.These cytokines could meet the essential criteria for radiosensitive biomarkers and can be used as radiation indicators.Our prediction models can conveniently and accurately estimate the exposure dose in irradiated organism.

Objects Obtained by y Quanta Irradiation with Threshold Energy of 10 MeV of Pure Gaseous He, under High Pressure, in CuBe2 Apparatus

A HeHPC （Helium high pressure chamber） filled up with pure gaseous helium at initial pressure about 1.1 bar was irradiated by braking γ-rays of 10 MeV threshold energy during 1.0 × 10^5 s at the electron beam current 22 - 24 μA. After irradiation, the residual pressure inside was equal to 430 bar. Synthesized foils of black color and other multiple objects were found inside the HeHPC mainly at the entrance window for γ-rays made from beryllium bronze as a plug of beryllium bronze HPC, at the inner surfaces of the reaction chamber made of high purity copper and at the copper collector. The element analysis, using SEM （Scanning electron microscopy） and MPRA （Microprobe roentgen analysis）, allowed us to establish that the foils consist predominantly of carbon and the smaller quantities of other elements from carbon to iron. An explanation for the observed elements is suggested on the basis of helium fusion reactions under the action of y-rays with the reactions taking place in giant stars （thermally activated）. The possible mechanism after 3α reaction is nα reactions and under barrier reactions. A second experiment with initial pressure of 3.05 kbar （with pressure drop by about 65 bar - after almost the same procedure of y-rays irradiation and with fully beryl bronze environment） suggests another possible nuclear reactions - He（Be, p）C, He（C, γ）O, and so on. The developed approach agrees well with a series of studies carried out by the authors where dense hydrogen and deuterium gases are acted on by γ-rays in the presence or absence of metals in the reaction chambers.

Influence of high-intensity pulsed ion beams irradiation on oxidation behavior of 316L stainless steel at 700℃

316L stainless steel samples, as a widespread used material, were irradiated with HIPIB at the beam parameters of ion energy 300 keV, current density 100, 200 and 300 A/cm2, shot number 10 and pulse duration 75 ns. The surface morphology and the phase structure in the near surface region of original and treated samples were analyzed with scanning electron microscopy (SEM) and X-ray diffractometry (XRD). It is shown that the HIPIB irradiation can smooth the surface of the samples, and the preferred orientation is present in the surface layer of irradiated coupons. The influence of HIPIB irradiation on the oxidation behavior of 316L stainless steel at 700℃for up to 100 h was investigated. Electron probe microanalysis (EPMA) was used to study the distribution of elements in the oxidation products. It is found that the oxidation behavior of the irradiated coupons depends greatly on the ion current density of HIPIB. HIPIB irradiation with ion current density of 100 A/cm2 slightly reduces the oxidation rate with respect to the unirradiated coupon. The improvement of the oxidation resistance can be attributed to more oxide of Cr that forms on the surface of the irradiated coupons. In contrast, HIPIB irradiation with ion current density of 200 or 300 A/cm2 is proved to be detrimental, causing a higher oxidation rate.

Extended damage range of(Al0.3Cr0.2Fe0.2Ni0.3)3O4 high entropy oxide films induced by surface irradiation

Irradiation makes structural materials of nuclear reactors degraded and failed.However,the damage process of materials induced by irradiation is not fully elucidated,mostly because the charged particles only bombarded the surface of the materials(within a few microns).In this work,we investigated the effects of surface irradiation on the indirect irradiation region of the(Al0.3Cr0.2Fe0.2Ni0.3)3O4 high entropy oxide(HEO)films in detail by plasma surface interaction.The results show that the damage induced by surface irradiation significantly extends to the indirect irradiation region of HEO film where the helium bubbles,dislocations,phase transformation,and the nickel oxide segregation were observed.

High-Efficiency Synthesis and Properties of Latent Pigment Red 272DPP-BOC by Microwave Irradiation

A high-efficiency synthesis method for a latent pigment of red pigment diketo-pyrrolo-pyrrole (Pig. Red 272:272DPP), which is important as a functional organic pigment, was investigated, and the investigation results revealed that irradiation of microwaves (MWs) for several seconds to 272 DPP in NMP (N-methyl-2-pyrrolidone) solvent yielded DPP latent pigment (272DPP-BOC) at a high yield of 86.2%. Two kinds of latent-pigment crystals, namely, red and yellow, were obtained by recrystallization, and it was found that the fluorescence-emission properties of the two kinds differ significantly. Single-crystal X-ray structural analysis showed that the difference in the fluorescence-emission properties of the two types is derived from the difference in their crystal structures.

Some Physical Properties of Graphite-Like Objects Obtained by γ Quanta Irradiation with Threshold Energy of 10 MeV of Pure Gaseous He, under High Pressure, in CuBe2 Apparatus

A HeHPC （helium high pressure chamber） filled up with pure gaseous helium at initial pressure about 1.1 kbar was irradiated by braking 7-rays of 10 MeV threshold energy during 1.0 × 10^5 s at the electron beam current （22-24） μA. After irradiation, the residual pressure inside was equal to 430 bar. Synthesized foils of black color and other multiple objects were found inside the HeHPC mainly at the entrance window for γ-rays made from beryllium bronze as a plug of beryllium bronze HPC, （published earlier） at the inner surfaces of the reaction chamber made of high purity copper and at the copper collector. Firstly, the element analysis, using SEM （scanning electron microscopy） and MPRA （microprobe roentgen analysis）, allowed us to establish that the foils consist predominantly of carbon and oxygen and smaller quantities of other elements up to iron. Two years later some physical properties such as （low） density, （high） resistivity, magnetic （high paramagnetic） and dielectric （medium relative dielectric constant） properties were determined. A new carbon reach structure was also postulated basing on obtained diffractometer data. The second used method （see text） for element content determination, in principle, has confirmed the previous one.

The effects of ^(60)Co γ-ray irradiation on the DC characteristics of enhancement-mode AlGaN/GaN high-electron-mobility transistors

The effects of ^60Co γ-ray irradiation on the DC characteristics of AlGaN/GaN enhancement-mode high-electron- mobility transistors （E-mode HEMTs） are investigated. The results show that having been irradiated by^60Co γ-rays at a dose of 3 Mrad （Si）, the E-mode HEMT reduces its saturation drain current and maximal transconductance by 6% and 5%, respectively, and significantly increases both forward and reverse gate currents, while its threshold voltage is affected only slightly. The obvious performance degradation of E-mode A1GaN/GaN HEMTs is consistent with the creation of electronegative surface state charges in the source-gate spacer and gate-drain spacer after being irradiated.

Effect of Exogenous Nitric Oxygen on Lipid Peroxidation and Chlorophyll Fluorescence in Wheat Leaves under High Temperature and Strong Irradiance Stress

[Objective] The study aimed to prove effects of NO on oxidative damage and photosynthetic apparatus at filling stage of wheat leaves under high temperature and irradiance stress.[Method] Yunong 949 was taken as experimental material to study the effects of sodium nitropprusside (SNP,an exogenous nitric oxide donor) at 0.1 mmol/L on protective enzyme activities, oxidative damage and fluorescence.[Result] The treatment with SNP (at 0.1 mmol/L) significantly increased the activity of SOD and APX, proline content, decreased the MDA content and relative electrical conductivity, Kept the higher Fv/Fm and lower Fo.[Conclusion] The adaptability of wheat with SNP treatment at 0.1 mmol/L was improved under high temperature and irradiance stress.

Deformation defects and electron irradiation effect in nanostructured Al-Mg alloy processed by severe plastic deformation

In order to explore the exact nature of deformation defects previously observed in nanostructured Al-Mg alloys subjected to severe plastic deformation, a more thorough examination of the radiation effect on the formation of the planar defects in the high pressure torsion （HPT） alloys was conducted using high-resolution transmission electron microscopy （HRTEM）. The results show that high density defects in the HRTEM images disappear completely when these images are exposed under the electron beam for some duration of time. At the same time, lattice defects are never observed within no-defect areas even when the beam-exposure increases to the degree that holes appear in the areas. Therefore, it is confirmed that the planar defects observed in the HPT alloys mainly result from the significant plastic deformation and are not due to the radiation effect during HRTEM observation.

Microstructure evolution of T91 steel after heavy ion irradiation at 550℃

Fe-Cr ferritic/martensitic(F/M)steels have been proposed as one of the candidate materials for the Generation IV nuclear technologies.In this study,a widely-used ferritic/martensitic steel,T91 steel,was irradiated by 196-MeV Kr^(+)ions at 550℃.To reveal the irradiation mechanism,the microstructure evolution of irradiated T91 steel was studied in details by transmission electron microscope(TEM).With increasing dose,the defects gradually changed from black dots to dislocation loops,and further to form dislocation walls near grain boundaries due to the production of a large number of dislocations.When many dislocation loops of primary a0/2<111>type with high migration interacted with other defects or carbon atoms,it led to the production of dislocation segments and other dislocation loops of a0<100>type.Lots of defects accumulated near grain boundaries in the irradiated area,especially in the high-dose area.The grain boundaries of martensite laths acted as important sinks of irradiation defects in T91.Elevated temperature facilitated the migration of defects,leading to the accumulation of defects near the grain boundaries of martensite laths.

Chemical Dosimetry during Alpha Irradiation: A Specific System for UV-Vis <i>in Situ</i>Measurement

This paper is devoted to the study of the potentiality of the Fricke dosimeter for the characterization of the highly energetic (62.1 MeV) α particles beams generated by a new cyclotron facility, namely ARRONAX started in 2009. Such for this high energetic α beam, in situ dosimetry is performed in order to avoid radiation safety inconvenience and to earn run time of irradiation. Therefore, an in situ Fricke dosimetry protocol is developed and its reliability is checked by comparison with other experiments carried out by using the traditional method (ex situ Fricke dosimetry) within another cyclotron facility (CEMHTI) and by comparison with literature data. To author’s knowledge, it is the first time that Fricke dosimetry is performed during the α irradiation experiment. The results of these in situ dosimetry experiments show that the value of ferric ions radiolytic yield (G(Fe3+) = (11.7 ± 1.2) 10–7 mol?J–1) extrapolated from literature data can be used for this higher energy of α particles (Eα = 62.1 MeV).

Aligned Elongation of Ag Nanoparticles Embedded in Silica Irradiated with High Energy Ni Ions

Metallic nanoparticle （NP） shapes have a significant influence on the property of composite embedded with metallic NPs. Swift heavy ion irradiation is an effective way to modify shapes of metallic NPs embedded in an amorphous matrix. We investigate the shape deformation of Ag NPs with irradiation fluence, and 357 MeV Ni ions are used to irradiate the silica containing Ag NPs, which are prepared by ion implantation and vacuum annealing. The UV-vis results show that the surface plasmon resonance （SPR） peak from Ag NPs shifts from 400 to 377nm. The SPR peak has a significant shift at fluence lower than 1 × 10^14 ions/cm2 and shows less shift at fluence higher than 1 × 10^14 ions/cm2. The TEM results reveal that the shapes of Ag NPs also show significant deformation at fluence lower than 1 × 10^14 ions/cm2 and show less deformation at fluence higher than 1 × 10^14 ions/cm2. The blue shift of the SPR peak is considered to be the consequence of defect production and Ag NP shape deformation, Based on the thermal spike model calculation, the temperature of the silica surrounding Ag particles first increases rapidly, then the region of Ag NPs close to the interface of Ag/silica is gradually heated. Therefore, the driven force of Ag NPs deformation is considered as the volume expansion of the first heated silica layer surrounding Ag NPs.

Synthesis of New Structures and Substances in Dense Gases H2, D2 and He under Irradiation by Braking 10 MeV y-rays in Cu0.98Be0.02 Pressure Chamber

High-pressure chambers filled with gaseous hydrogen （HHPC）, deuterium （DHPC） and helium （HeHPC） under different initial pressures from about I kbar up to 3 kbar were irradiated with braking γ-rays of threshold energy 10 MeV during varying periods of exposure at the electron beam currents 22-24μA. Upon opening of these chambers, a lot of new synthesized structures with unusual element compositions very different from the initial ones were found. The described phenomena agree well with a series of studies by authors carried out under the action of γ-rays on dense gases of hydrogen, deuterium and helium in the presence of chosen metals in the reaction chamber.

Irradiation Response of Adipose-derived Stem Cells under Three-dimensional Culture Condition

Objective Adipose tissue distributes widely in human body. The irradiation response of the adipose cells in vivo remains to be investigated. In this study we investigated irradiation response of adipose-derived stem cells (ASCs) under three-dimensional culture condition. Methods ASCs were isolated and cultured in low attachment dishes to form three-dimensional (3D) spheres in vitro. The neuronal differentiation potential and stem-liked characteristics was monitored by using immunofluoresence staining and flow cytometry in monolayer and 3D culture. To investigate the irradiation sensitivity of 3D sphere culture, the fraction of colony survival and micronucleus were detected in monolayer and 3D culture. Soft agar assays were performed for measuring malignant transformation for the irradiated monolayer and 3D culture. Results The 3D cultured ASCs had higher differentiation potential and an higher stem-like cell percentage. The 3D cultures were more radioresistant after either high linear energy transfer (LET) carbon ion beam or low LET X-ray irradiation compared with the monolayer cell. The ASCs’ potential of cellular transformation was lower after irradiation by soft agar assay. Conclusion These findings suggest that adipose tissue cell are relatively genomic stable and resistant to genotoxic stress.