Radiation effect of the device becomes more important with the development of aerospace due to them may change the state or even destroy the device.The major types of the radiation effect include single event effect(SEE),total ionizing dose(TID)and displacement damage(DD).SEE can be caused by ions incidence the sensitive region of the device and changes the potential of the electrode.TID can be caused by ions incidence at the material of the device and leads to the charge accumulate on the Si-SiO2 interface.In general,the SEE and TID often occur in random-access memory(RAM),and the DD often occur in image sensor.Therefore,the researching and esti-mating the risk of radiation effect on the device before use is necessary.Much study has been report during the last decades,but most of them focus on the single radiation effect.Recently,the synergistic effect becomes attention because the development of space nuclear power and it reflectes the real radiation environment of the device.In this paper,the static random access memory(SRAM)was used for research the synergistic effects by using the China Institute of Atomic Energy HI-13 Tandem Accelerator and the 60Co irradiation device.The SRAM was radiated by the gamma ray and then the different heavy ions.Yet it's worth noting that the sequential irradiation method is a common research method of synergistic effect.In the total ionizing dose experiment,different doses on the device were chosen,such as 300,500 and 750 krad(Si).Mean-while,the dose rate keeps the same on 90 krad(Si)/h.In the single event effect experi-ment,different ion energy on the device was chosen,such as 5.0,13.9,21.9 and 37.4 MeV·cm2/mg.The time interval between two different radiations keeps brief for decreasing the annealing effect.Single event upset of the device was measured by the self-developed testing system.A typical soft errors calculation method under the mixed beam environments was proposed.By using this method,the on-orbit soft errors of the device in the space nuclear power were calculated.Meanwhile,the uncertainty of the method was distinguished and calculated including the uncertainty of total dose,single event upset number,flux and the fitting process.Type A and B uncertainties were synthesised for the final uncertainty.Research result suggests the synergistic effects may reduce the soft errors compared to simple single event effect.

The effect of the total ionizing dose (TID) on the static random access memory (SRAM) is conducted on the 60Co radioactive source in the China Institute of Atomic Energy. The study explores the influence of the device process size, dose rate, temperature and total dose on TID. The results indicated that within a certain range, the dose rate had little influence on the TID of the device. The larger the characteristic size of the device, the greater TID effect, while the higher temperature, the weaker the total dose effect. In addition, the typical dose rate and the uniformity of the source are achieved. The research of the paper provide an insight into radiation hardening, particularly in the aerospace and the nuclear industries.

Exposure to environmental ionizing radiation (IR) is ubiquitous, and large-dose exposure to IR is known to cause DNA damage and genotoxicity which is associated with an increased risk of cancer. Whether such detrimental effects are caused by exposure to low-dose IR is still debated. Therefore, rapid and early estimation of absorbed doses of IR in individuals, especially at low levels, using radiation response markers is a pivotal step for early triage during radiological incidents to provide adequate and timely clinical interventions. However, there is currently a crucial shortage of methods capable of determining the extent of low-dose IR exposure to human beings. The phosphorylation of histone H2AX on serine 139 (designated γ-H2AX), a classic biological dosimeter, can be used to evaluate the DNA damage response. We have developed an estimation assay for low-level exposure to IR based on the mass spectrometry quantification of γ-H2AX in blood. Human peripheral blood lymphocytes sensitive to low-dose IR, maintaining low temperature (4°C) and adding enzyme inhibitor are proven to be key steps, possibly insuring that a stable and marked γ-H2AX signal in blood cells exposed to low-dose IR could be detected. For the first time, DNA damage at low dose exposures to IR as low as 0.01 Gy were observed using the sensitive variation of γ-H2AX with high throughput mass spectrometry quantification in human peripheral blood, which is more accurate than the previously reported methods by virtue of isotope-dilution mass spectrometry, and can observe the time effect of DNA damage. These in vitro cellular dynamic monitoring experiments show that DNA damage occurred rapidly and then was repaired slowly over the passage of post-irradiation time even after exposure to very low IR doses. This assay was also used to assess different radiation exposures at the in vitro cellular level. These results demonstrate the potential utility of this assay in radiation biodosimetry and environmental risk assessment.

Although proton irradiation is ubiquitous in outer space as well as in the treatment of human diseases, its effects remain largely unclear. This work aimed to investigate and compare the composition of gut microbiota composition of mice in different species exposed to high-dose radiation. Male Balb/c mice and C57BL/6J mice were irradiated at a high dose (5Gy). Fecal specimens before and after irradiation were subjected to high-throughput sequencing (HTS) for the amplification of 16S rRNA gene sequences. We observed substantial changes in gut microbial composition among mice irradiated at high doses compared to non-irradiated controls. The changes included both the alpha and beta diversities. Furthermore, there were 11 distinct alterations in the irradiation group compared to the non-radiation control, including the families Muribaculaceae, Ruminococcaceae, Lactobacillus, Lachnospiraceae_NK4A136, Bacteroides, Alistipes, Clostridiales, Muribaculum, and Alloprevotella. Such alterations in the gut microbiome were accompanied by alterations in metabolite abundances, while at the metabolic level, 32 metabolites were likely to be potential biomarkers. Some alterations may have a positive effect on the repair of intestinal damage. Simultaneously, metabolites were predicted to involve multiple signal pathways, such as Urea Cycle, Ammonia Recycling, Alpha Linolenic Acid and Linoleic Acid Metabolism, Ketone Body Metabolism, Aspartate Metabolism, Phenylacetate Metabolism, Malate-Aspartate Shuttle, Arginine and Proline Metabolism and Carnitine Synthesis. Metabolites produced by proton irradiation in the microbial region play a positive role in repairing damage, making this area worthy of further experimental exploration. The present work offers an analytical and theoretical foundation to investigate how proton radiation affects the treatment of human diseases and identifies potential biomarkers to address the adverse effects of radiation.Importance:The space radiation environment is extremely complex, protons radiation is still the main component of space radiation and play an important role in space radiation. We proposed for the first time to compare the feces of Balb/c and C57BL/6J mice to study the changes of intestinal flora before and after proton irradiation. However, the effect of proton irradiation on the gut microbiome of both types of mice has not been previously demonstrated. After proton irradiation in two kinds of mice, we found that the characteristics of intestinal microbiome were related to the repair of intestinal injury, and some metabolites played a positive role in the repair of intestinal injury.

Proton radiation (PR) and microgravity (μG) are two key factors that impact living things in space. This study aimed to explore the combined effects of PR and simulated μG (SμG) on bone function. Mouse embryo osteoblast precursor cells (MC3T3-E1) were irradiated with proton beams and immediately treated with SμG for 2 days using a three-dimensional clinostat. All samples were subjected to cell viability, alkaline phosphatase (ALP) activity and transcriptome assays. The results showed that cell viability decreased with increasing doses of PR. The peak ALP activity after PR or SμG alone was lower than that obtained with the non-treatment control. No difference in cell viability or ALP activity was found between 1 Gy PR combined with SμG (PR-SμG) and PR alone. However, 4 Gy PR-SμG resulted in decreased cell viability and ALP activity compared with those obtained with PR alone. Furthermore, Gene Ontology analysis revealed the same trend. These results revealed that PR-SμG may lead to reductions in the proliferation and differentiation capacities of cells in a dose-dependent manner. Our data provide new insights into bone-related hazards caused by multiple factors, such as PR and μG, in the space environment.

目的 研究100 MeV质子照射对人宫颈癌HeLa细胞线粒体氧化损伤及其作用机制.方法 采用中国原子能科学研究院100 MeV强流质子回旋加速器照射人宫颈癌HeLa细胞,剂量率为0.8 Gy/min.按照射剂量分为未照射组(0 Gy)、低剂量照射组(0.5 Gy)和高剂量照射组(8 Gy),分别于照射后24、48和72 h采用CCK-8法检测细胞增殖情况,流式细胞术检测细胞凋亡变化;DCFH-DA标记法检测照射后12～72 h活性氧(ROS)含量动态变化;线粒体呼吸链复合体Ⅰ检测试剂盒检测照射后24和48 h线粒体呼吸链复合体Ⅰ活性;mRNA芯片杂交检测分析8 Gy质子照射12和24 h后HeLa细胞的差异表达基因.结果 与未照射组相比,低剂量照射组细胞增殖、细胞凋亡、ROS生成以及线粒体呼吸链复合体Ⅰ活性均无明显改变.高剂量照射组在照射后72 h细胞增殖显著降低;24、48和72 h细胞凋亡呈时间依赖性增加;细胞ROS含量在照射后16～24 h明显增加,36 h后逐渐下降;照射后24和48 h,细胞线粒体呼吸链复合体Ⅰ活性降低.KEGG分析提示,8 Gy质子照射24 h后诱导表达差异变化明显的基因主要集中在丝裂原活化蛋白激酶(MAPK)信号通路、PI3K/Akt信号通路和过氧化物酶体增殖物(PPAR)激活受体信号通路等.结论 100 MeV质子高剂量照射可抑制人宫颈癌HeLa细胞增殖,促进凋亡,且此改变可能与细胞氧化应激和线粒体呼吸链复合体Ⅰ活性受到抑制有关.

The evolution of defects with isochronal annealing between 373 and 1273 K in 316L stainless steels, irradiated by helium ions at room temperature (RT), has been studied by the slow positron Doppler broadening spectroscopy (DBS). The results showed that with annealing temperature between RT and 673 K, the S parameters of sample were maintained. It indicates that below 673 K, on the one hand, some vacancies introduced by irradiation were gathered to form vacancy clusters and on the other hand, some vacancies migrated and recovered. From 773 K to 1073 K, there was continuous growth of HenVm cluster, resulting in rapid increasing of S parameter. After 1073 K, unstable HenVm clusters dissociated into vacancies and He atoms. The vacancies were vanished rapidly, which decreases the concentration of vacancy defects, leading to decline of S parameter.

质子辐射生物学效应是太空放射生物学和质子束放疗研究的重要基础,可为空间环境下人员的危险性评估以及质子治疗优化设计提供科学依据.依托加速器建立相应的生物样本辐照技术是开展此类研究的前提条件.中国原子能科学研究院最近建立的100 MeV强流质子回旋加速器提供的中能质子束流为目前国内能量最高,特别适合用于太空放射生物学和质子治疗相关研究.本研究中,利用在束和离线等多种手段建立了中能质子束流诊断和剂量测量方法,对加速器引出的100 MeV质子照射野大小、均匀性等束流品质以及剂量测量系统准确性进行了分析和评估.结果表明,对光子剂量响应好的LiF(Mg,Ti)热释光探测器,对90 MeV质子同样具有良好的剂量响应关系,可作为中能质子剂量准确性评估的手段之一.在5.0 cm×5.0 cm照射野范围内,加速器引出的100 MeV质子束流的均匀性好于90％,在线剂量测量系统准确性好于93％,束流品质和剂量测量条件基本满足辐射生物学的要求,可为质子辐射生物学效应研究的开展提供可靠保障.

The aim of investigating the annealing effect induced by helium/hydrogen ion irradiation on the micro-defects of ferritic/martensitic (FM) steel is to gain a basic understanding on the development of fusion reactor components. In this study, 250 keV He2+ and 130 keV H+ were used for irradiation. Then, micro-defects were annealed isochronally between 423 K and 673 K, and were monitored by the slow positron beam Doppler broadening technique. The results revealed that the He ions implanted into the steels combined with vacancies to form HenVm clusters, and were likely to grow and form overpressured HenVm, clusters by thermal activation. The S-W line of the irradiated specimen deviated the line segment, which indicates the formation of overpressured HenVm clusters in the He-irradiated steel. Moreover, the AS-E curves indicate residual vacancies that were induced by He-irradiation at 723 K and later migrated toward the bulk of the sample at 423 K. Subsequently, the vacancies tended to migrate to the sample surface as the annealing temperature increased. The S parameter of the He + H irradiated sample was much larger than that of all other samples, owing to the synergy effect of H and He. After annealing at 423 K, the H-V clusters decomposed and the hydrogen atoms in the He + H-irradiated sample escaped from the surface leaving a large number of vacancies.

A large number of dislocation networks were introduced in to 316L stainless steel by cold rolling. Subsequently, low energy (40 eV) helium ions were implanted by exposing the steel to helium plasma. Thermal desorption and positron annihilation spectroscopy were used to study the behavior of helium in the presence of dislocations, with emphasis on helium self-trapping and migration behaviors. Helium desorption behaviour from different helium trapping states was measured by the thermal desorption spectroscopy. Most of the helium desorbed from the HemVn clusters, and the corresponding desorption peak is located at similar to 650K. The desorption peak from helium-dislocation clusters (HemD) is at approximately 805 K. The effect of annealing on the defect evolution was investigated by positron annihilation spectroscopy. For the specimen exposed to helium plasma without displacement damage, the increment of S parameter meant the existence of helium self-trapping behavior (HemVn). Helium atoms could diffuse two to three orders of magnitude deeper than the implantation depth calculated by SRIM. The diffusing helium atoms were gradually trapped by dislocation lines and formed HemD. Elevated temperatures enhance the self-trapping behavior and cause helium atoms to dissociate/desorb from the HemVn clusters, increasing the S parameters at 473-673 K. The gradual recovery of vacancies in the clusters decreased the S parameter above 673 K.

Polycrystalline nickel was irradiated using 50 keV He ions at room temperature. The irradiated fluences were 5 × 1013, 5 × 1014, and 5 × 1015 He+ cm−2, respectively. Positron annihilation Doppler broadening spectroscopy (DBS) was used to characterize the irradiation-induced defect evolution. The DBS results show that a large amount of vacancy defects were introduced in the specimens after helium irradiation. In addition, the DBS data could be also interpreted as the formation of helium-vacancy (HenVm) clusters due to combination between vacancies and helium atoms.

Well-annealed 316L stainless steel was first cold rolled to 10% and 20% reductions in thickness and then irradiated by 50 keV He+ to a dose of 1 x 10(20) He+/m(2) at room temperature. Thermal desorption spectroscopy was used to investigate the helium desorption behaviour at different helium trapping states. The results showed that high-density dislocations had stronger inhibitory effect for helium desorption at temperatures from 800 to 1200 K. Positron annihilation Doppler broadening spectroscopy measurements were used to investigate the distribution of helium irradiation-induced defects. The S-E and Delta S-E plots clearly demonstrated that the helium irradiation-induced defects were trapped and restricted in motion by dislocations. The interaction between dislocations and helium irradiation-induced defects in deformed 316L stainless steel was investigated.

The purpose of the study detailed in this paper is to investigate the evolution of microstructural defects in the Fe‐9Cr binary alloy induced by isochronal annealing from 373 to 1223 K. Positron annihilation lifetime spectroscopy (PALS), Doppler broadening spectroscopy (DBS), positron annihilation lifetime calculation, and transmission electron microscope (TEM) are used to analyze and characterize the change of defect concentration, defect type and the micro‐morphology in the Fe‐9Cr alloy as a function of the annealing temperature. The experimental results showed that, a large number of vacancies and dislocations were found to exist in the untreated Fe‐9Cr alloy. The monovacancy (186.2 ps) in the Fe‐9Cr alloy migrated during annealing from room temperature to 573 K. The annealing temperature at 773 K produce aggregation of dislocations and the formation of dislocation networks, as well as their heterogeneous distribution. When the temperature is further increased to 1073 K, most of the vacancies and dislocations are recovered and a bcc‐fcc phase transmition occurred in Fe‐9Cr model alloy. The dislocation density is continuous decreased with the increase of annealing temperature, the recovery is obvious from 773 K annealing to 1073 K annealing in Fe‐9Cr alloy.

An element analysis method, coincidence Doppler broadening spectroscopy of slow positron annihilation, was employed to detect helium in ion-irradiated Fe9Cr alloys. Spectra with higher peak to background ratio were recorded using a two-HPGe detector coincidence measuring system. It means that information in the high-momentum area of the spectra can be used to identify helium in metals. This identification is not entirely dependent on the helium concentration in the specimens, but is related to the structure and microscopic arrangement of atoms surrounding the positron annihilation site. The results of Doppler broadening spectroscopy and transmission electron microscopy show that vacancies and dislocations were formed in ion-irradiated specimens. Thermal helium desorption spectrometry was performed to obtain the types of He traps.

Solution annealed type 316L austenitic stainless steels were irradiated using 2 MeV Fe ions at room temperature. The implanted fluences were 2×1012 ions/cm2 and 1×1013 ions/cm2, respectively. Variable mono-energetic positron beam was performed to characterize the evolution of microstructure and irradiation induced defects. Results show that large amount of vacancy defects formed after heavy ion irradiation. In which, some of mono-vacancies might migrate to form small-sized clusters at room temperature. After irradiation, implanted Fe atoms mainly be interstitials atoms, but some Fe atoms might recombine with vacancies due to their high mobility, which could decrease the defect concentration, effectively.

Dislocations would be induced after plastic deformation, which might change the mechanical properties of solids. FeCrNi austenitic model alloy and its Mo-diluted alloy were cold rolled with different degree of thickness reduction. Positrons are sensitive to point defects, which are easily trapped and annihilated around the trapping sites. The mean positron lifetimes have been used to estimate the average dislocation concentration in solids. Meanwhile, the trapping efficiency μ was calculated from the lifetime results. The trapping efficiency value is estimated about 3.31×10-7 cm3s-1 for FeCrNi alloy and 3.31×10-7 cm3s-1 for Mo-diluted alloy, respectively. The increment of the hardness value during plastic deformation is related to the increase of the dislocation density and dislocation pile up in solids.

The contribution of positron source for the results of a positron annihilation lifetime spectrum (PALS) is simulated using Geant4 code. The geometrical structure of PALS measurement system is a sandwich structure: the 22Na radiation source is encapsulated by Kapton films, and the specimens are attached on the outside of the films. The probabilities of a positron being annihilated in the films, annihilated in the targets, and the effect of positrons reflected back from the specimen surface, are simulated. The probability of a positron annihilated in the film is related to the species of targets and the source film thickness. The simulation result is in reasonable agreement with the available experimental data. Thus, modification of the source contribution calculated by Geant4 is viable, and it beneficial for the analysis of the results of PALS.

ZnS thin films have been prepared by sulfurizing zinc thin films deposited on glass substrate by magnetron sputtering for two hours.The microstructure defects,crystallizations and surface morphology of zinc films sulfurized at different temperature were analyzed by PAT (positron annihilation technique),XRD(X-ray diffraction) and SEM (Scanning electron microscopy),respectively.For analyzing the structure defect of four samples with different sulfurization temperature,PAT has been used to obtain the relative concentration of defects.With the positron energy range of 1.5～4.5 keV,the S parameter of ZnS films is minimum.It demonstrates that ZnS films produced at 445 ℃ have the minimum structural defect concentration and the highest density.XRD results show that films are blende structure with the preference of (111) orientation above 445 ℃.And from the result of SEM,because of ZnS films recrystallization,the crystal grains obviously become large and dense at 445 ℃.

Transmutation helium may causes serious embrittlement which is considered to be due to helium from clustering as a bubble in materials. Suppression of transmutation helium can be achieved by introducing trapping sites such as dislocations and impurities in materials. Here, effects of intentionally-induced dislocations and hydrogen on helium migrate and release behaviors were investigated using thermal desorption spectrometry (TDS) technique applied to well-annealed and cold-worked Fe9Cr alloys irradiated by energetic helium/hydrogen ions. Synchronous desorption of helium and hydrogen was observed, and the microstructure states during helium release at different temperatures were analyzed. High thermally stable HenD type complexes formed in cold-worked specimens, resulting in the retardation of helium migration and release. The existence of hydrogen will strongly affect the thermal helium desorption which could be reflected in the TDS spectrum. It was confirmed that hydrogen retained in the specimens can result in obvious delay of helium desorption.

The pure iron was cold rolled with the thickness reduction from 0％ to 75％.The microstructure defects,crystallographic structure and morphology of deformed specimens were characterized by positron annihilation technique (PAT),X-ray diffraction (XRD) and transmission electron microscopy (TEM).The XRD results show that the intensity of (200) increased with increasing deformation,673 K heat-treatment promote the preference of (200) and the grain size of (200) was increased.The PAT results show that the vacancy type defect was annihilated at 673 K and the dislocation type defects start to annihilate at 723 K.