The length of the photon beam transportation of Shanghai High repetitioN rate XFEL and Extreme light facility (SHINE) exceeds 1 km, the angular vibration of reflecting mirrors would be magnified at the endstations due to the long-distance transportation.

This study aims to explore the possibility of suppressing the angular vibration by using a dynamic vibration absorber.

According to the big pitch angular vibration of the mirror system at 14.6 Hz, a dynamic vibration absorber was designed with variable stiffness aiming at suppressing the vibration of mirror system for SHINE.

By tuning the nature frequency of the dynamic vibration absorber designed in this study at 14.6 Hz, results show that the vibration of reflecting mirrors at 14.6 Hz is reduced from 154 nard to 27.9 nrad, while vibrations at other frequencies are not disturbed, the total vibration is improved from 193.2 nrad to 76.9 nrad.

This indicated that the certain angular vibration of the mirror system could be suppressed by dynamic vibration absorber, which provided a new solution for angular vibration control of the advanced X ray light sources.

⁷Be and ²¹⁰Pb are the main radionuclides for monitoring the quality of the radiation environment of atmospheric aerosols, and the internal irradiation caused by their adsorption into aerosols and entry into the human body will be harmful to the human body, so it is of great significance to explore the characteristics and mechanisms of their spatial and temporal distribution and dose contribution.

This study aims to investigate the differences in the spatial and temporal distributions of atmospheric ⁷Be and ²¹⁰Pb and the mechanisms of these differences.

In this paper, 75 aerosol samples were collected from Nanning city, from January 2015 to December 2017 and from January 2019 to May 2022 using an ultra-high-flow air aerosol sampler, and the activity concentrations of ⁷Be and ²¹⁰Pb in the aerosol were measured and analyzed using a high-purity germanium (HPGe) γ-spectrometer. The activity concentration data of ⁷Be and ²¹⁰Pb were systematically collected in 17 areas of our country, as well as PM_2.5, PM₁₀ and O₃ air concentration data from January 2014 to November 2023 in Nanning city. Finally, the Lagrangian inverse trajectory analysis technique based on the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, combined with the clustering analysis method based on MeteoInfo software, was employed to analyze the seasonal characteristic control mechanism of ⁷Be and ²¹⁰Pb.

The activity concentrations of ⁷Be in 41 aerosol samples from January 2019 to May 2022 ranges from 0.27 mBq·m^-3 to 11.95 mBq·m^-3, with a mean value of (3.68±0.51) mBq·m^-3; the activity concentrations of ²¹⁰Pb in 60 aerosol samples from January 2015 to December 2017 and from January 2019 to February 2021 ranges from 0.23 mBq·m^-3 to 4.33 mBq·m^-3, with a mean value of (1.51±0.13) mBq·m^-3. Combining the ⁷Be and ²¹⁰Pb activity concentration data in 17 areas of China, the seasonal distribution of ⁷Be and ²¹⁰Pb activity concentrations in the atmosphere of China is characterized by an overall high in winter and spring, and a low in summer and autumn, but ⁷Be reaches its maximum value in spring while ²¹⁰Pb in winter. The correlation analysis shows that ⁷Be has a significant positive correlation with PM_2.5, PM₁₀, O₃, and has the best correlation with PM₁₀. ²¹⁰Pb has a significant positive correlation with PM_2.5 and PM₁₀ and has the best correlation with PM_2.5, while it is not correlated with O₃. The traceability analysis of air masses in Nanning city of the 2021 shows that the summer air masses mainly come from the oceanic air masses in the south with lower particle concentration, and the winter air masses mainly come from the continental air masses in the north with higher particle concentration. Combining the ⁷Be and ²¹⁰Pb activity concentration data in 17 areas of China, there are effects in the spatial distribution of ⁷Be and ²¹⁰Pb activity concentrations. The latitudinal effects: the mean ²¹⁰Pb activity concentration in the area north of about 40°N (3.20±0.24) mBq·m^-3 is about 2.2 times higher than that in the area south of about 40°N (1.48±0.06) mBq·m^-3; the mean value of ⁷Be activity concentration in the area north of about 35°N (7.44±0.26) mBq·m^-3 is about 1.9 times of that in the area south of about 35°N (3.92±0.19) mBq·m^-3. The altitudinal effect: the ⁷Be activity concentration is greater at high altitude than at low altitude. Based on the average of winter-spring and summer-autumn activity concentrations of ⁷Be and ²¹⁰Pb in 17 regions of the country, it can be estimated that the radiation dose due to ⁷Be and ²¹⁰Pb in winter-spring (42.08 μSv·a^-1) is about 1.4 times higher than that in summer-autumn (31.00 μSv·a^-1). Integration of monitoring data on activity concentrations of ⁷Be and ²¹⁰Pb in 17 regions of the country reveals that the annual effective dose due to ⁷Be and ²¹⁰Pb in the area north of 40°N (65.48 μSv·a^-1) is about 2.0 times higher than that in the area south of 35°N (32.75 μSv·a^-1). The mean annual pending effective doses due to ⁷Be and ²¹⁰Pb are 2.47×10^-3 μSv·a^-1 and 33.57 μSv·a^-1, respectively.

⁷Be and ²¹⁰Pb are adsorbed on the particulate matter and transported in the atmosphere, and the PM_2.5 and PM₁₀ concentrations are low in summer and autumn while high in winter and spring due to the monsoon regulation, so the ⁷Be and ²¹⁰Pb show the seasonal distribution characteristics of low in summer and autumn and high in winter and spring. The highest ⁷Be activity concentration in spring is related to the "spring leakage", while the highest ²¹⁰Pb activity concentration in winter is mainly influenced by the Eurasian land-based air masses in the north. The latitudinal effect of ²¹⁰Pb is probably related to the large amount of particulate matter brought by the northwest land-source winds in winter and the combustion process in winter heating system. The latitudinal effect of ⁷Be may be attributed to the "spring leakage" of ⁷Be that occurs in mid-latitudes in the spring. The altitudinal effect of ⁷Be is controlled by the top-down transport of ⁷Be from the stratosphere to the troposphere.

Bone fracture is an important factor affecting the life quality and mortality of elderly individuals, and its pathogenesis involves the imbalance of bone metabolism maintained by osteoblasts (OB) and osteoclasts (OC). ⁹⁹Tc-MDP is a drug for the targeted treatment of osteoporosis. While it can directly inhibit OC activity, there have been no in vivo data on its ability to induce OB activity.

This study aims to evaluate the effect of ⁹⁹Tc-MDP on osteogenesis in the treatment of osteoporosis.

In this study, a rat model of osteoporosis after ovariectomy were constructed to reflect the early process of osteoporosis formation, including calcium loss and bone mineral density decrease. Then, experimental rats were randomly divided into 4 groups, i.e., negative control group, model control group, ⁹⁹Tc-MDP treatment group and zoledronic acid treatment group, with 5 rats in each group (a total of 20 rats). Subsequently, the dynamic changes of osteoblast indexes such as blood calcium level and blood phosphorus content, after ⁹⁹Tc-MDP treatment were detected at the cellular, metabolic, and genetic levels to evaluate the effect of ⁹⁹Tc-MDP on osteogenesis in the treatment of osteoporosis.

Experimental comparison results demonstrate that ⁹⁹Tc-MDP effectively inhibits the osteoporosis process and reverses bone mineral density loss by inducing OB activity, achieving the suppression of bone decline at 4 weeks and returning to the preoperative level at 8 weeks. Although the OB activity induced by ⁹⁹Tc-MDP is altered to similar levels in OB cells of normal rats, but there is no significant change in the expression of major bone-related genes. The multifactor analysis results suggest that IL-6 can be the key factor and monitoring index.

⁹⁹Tc-MDP can stimulate OB activity as a powerful supplement to inhibiting OC activity, which is beneficial to the maintenance of OB/OC homeostasis.

²²³Ra SPECT/CT (Single Photon Emission Computed Tomography/Computed Tomography) imaging provides critical information for evaluating the efficacy of bone-targeted radiotherapy in patients with metastatic castration-resistant prostate cancer (mCRPC).

This study aims to explore the optimal imaging parameters for ²²³Ra SPECT/CT using three standard phantoms: the Carlson model, PET/CT model, and Hoffman 3D brain model.

Firstly, quality control tests were performed on all three phantoms using a GE NM/CT 670 ES system with ⁹⁹Tc^m to establish standard reference images. Then, ²²³Ra SPECT/CT imaging was conducted by injecting 3.7 MBq of ²²³RaCl₂ into each phantom, with acquisition parameters set at 84 keV and 140 keV energy peaks with 10% windows, using both LEHP and HEGP collimators, and acquisition times ranging from 30 min to 100 min. Finally, image reconstruction was performed using Butterworth filters (f_c=0.48, p=10) and three-dimensional ordered subset expectation maximization (3D OSEM) algorithms with 5 subsets and 10 iterations, followed by qualitative assessment of image quality by two experienced nuclear medicine physicians.

The ²²³Ra SPECT/CT images acquired with HEGP collimators demonstrate significantly better resolution and contrast compared to those with LEHP collimators. In the Carlson model, the minimum detectable hot and cold zone diameters are both 22.3 mm, with acceptable linearity but suboptimal uniformity. PET/CT model ²²³Ra SPECT/CT images are acceptable, but there are certain differences between the transverse, coronal, and sagittal image fusion matching degree and attenuation correction dispersion index compared to the ⁹⁹Tc^m SPECT/CT quality control images. The Hoffman brain phantom ²²³Ra SPECT/CT images show less distinct brain sulci, gyri, and basal ganglia nuclear groups, indicating a need to further improve image quality.

²²³Ra SPECT/CT imaging is feasible for clinical applications, with optimal parameters including an 84 keV±20% energy window and HEGP collimation. While the current protocol achieves diagnostic-quality images with a spatial resolution of 22.3 mm for both hot and cold lesions, further parameter optimization is needed to improve image uniformity and detailed visualization of complex structures. These findings provide a foundation for clinical ²²³Ra SPECT/CT imaging protocols that can enable more accurate assessment of ²²³Ra therapy distribution and response.

Traditional semiconductor detectors cannot operate for long periods in high-dose-rate radiation environments. Diamond detectors, with their wide bandgap, high carrier mobility, high radiation hardness, and fast time response, are suitable for radiation detection in extreme environments.

This study aims to investigate the electrical properties, energy resolution, charge collection efficiency, and response characteristics to ⁶⁰Co gamma radiation of single crystal diamond (SCD) detectors.

Initially, the SCD material in the size of 4.5 mm×4.5 mm×0.3 mm from Element Six Ltd. UK was characterized using Atomic Force Microscope (AFM), X-ray Diffraction (XRD) and Photoluminescence Spectroscopy (PL). Subsequently, oxygen-terminated diamond detector was fabricated. Then, the dark current of the detector was measured using a Keithley 4200 Semiconductor Parameter Analyzer, and the energy resolution and charge collection efficiency of the fabricated SCD detector were obtained by comparing them with a silicon detector using a ²³⁸Pu α source. Finally, the response and stability of the SCD detector to ⁶⁰Co gamma dose rates in both current and pulse modes were studied and compared with commercial diamond detector from MICRON, UK.

The detector's electron and hole charge collection efficiencies are as high as 98.9% and 99.2%, respectively, with energy resolutions of 2.54% and 2.86%. The fabricated SCD diamond detector operates in pulse mode and current mode, with gamma dose rate responses ranging from 0.001 3 Gy?h^-1 to 64 Gy?h^-1 and from 0.2 Gy?h^-1 to 64 Gy?h^-1, respectively. The linear correlation can reach over 99.3%, which is superior to the commercial MICRON diamond detector.

Measurement results demonstrate that SCD detector can be applied to real-time gamma dose measurement. Investigating the response of diamond detectors to gamma rays helps to further in-depth research on neutron/gamma-ray discrimination methods based on single-crystal diamond detectors, and can be applied to real-time gamma dose measurement.

As a new type of optoelectronic detector developed in recent years, SiPM (Silicon Photomultiplier) has the advantages of low cost, miniaturization and low working voltage. It has been widely used in particle detection, medical imaging, high-energy physics and other fields, especially in the field of large-area particle imaging. However, large-area imaging necessitates a substantial number of SiPMs, making it essential to conduct batch screening, aging, and performance measurements for these devices.

This study aims to design a batch performance measurement system for SiPMs that enables the simultaneous aging and performance assessment of 512 SiPMs (the number can be further expanded).

Firstly, a SiPM batch aging and performance measurement system, mainly consisting of a digital multimeter, relay, low-voltage power supply, constant temperature and humidity box, and host computer was designed. Then, an online control program was developed in Python to measure the aging performance of 512 SiPMs under conditions of 30 °C, 40% relative humidity and an operating voltage of 29 V. Finally, the relative derivative method was apllied to the study of the variation in the breakdown voltage of the SiPMs was studied under different temperatures (25 °C, 27 °C, 29 °C, and 30 °C) at voltages ranging from 22 V to 29 V and a constant relative humidity of 40%.

The results show that the dark current of SiPM decreases significantly after aging, indicating that the aging process is beneficial for rapidly stabilizing the performance of a large number of SiPMs. After aging, the average breakdown voltage of SiPM is 24.88 V (@25 ℃), which is in good agreement with the manufacturer's data of 25 V (@25 ℃), and the breakdown voltage increased with increasing temperature, and a linear fit yielded a temperature coefficient of 35.3 mV·°C^-1, with a correlation coefficient (R²) of 0.996.

The results demonstrate that the developed system for batch aging and performance measurement of SiPM can be simultaneously used to age a large number of SiPMs, rapidly stabilizing their performance. The system can quickly obtain performance parameters for a large quantity of SiPMs, including I-V characteristics, breakdown voltage, temperature coefficients and so on, hence providing significant reference value for the batch screening and performance testing of SiPM.

The operational characteristics of passive residual heat removal systems (PRS) under marine conditions are crucial for the thermal and hydraulic safety of offshore floating nuclear power plants.

This study aims to verify the applicability of the re-developed RELAP5 code under inclined conditions.

Based on the small-scaled secondary side of the PRS experimental device, simulation of the experiments were carried out by using the secondary-developed RELAP5 code under the operating conditions of the inclination angle from -24° to +24°. Then, a comparative analysis of experimental data was performed to verify the applicability of this secondary-developed code.

The results show that the length of the condensing section in the C-type heat exchanger is changed under inclination conditions, and the larger the tilt angle, the better the overall heat transfer effect is achieved. Besides, the re-developed RELAP5 code can effectively predict changes in the system operating characteristics under tilt conditions, and the deviation between the calculated results and the experimental values is within ±4%.

The results of this study provides some reference for the design of the secondary side passive heat removal system under marine conditions.

After a steam generator tube rupture (SGTR) accident occurs in a lead-bismuth eutectic (LBE) alloy-cooled reactor, supercooled water on the secondary side is injected into the high-temperature molten LBE on the primary side. Possible consequences arising from SGTR include LBE solidification, damage to the reactor components caused by pressure waves, and unexpected reactivity owing to steam migration into the reactor core.

This study aims to conduct a computational fluid dynamics pre-computation for the LBE alloy-cooled reactor to clarify the phenomena and determine the working conditions of LBE-water interaction.

Firstly, a large experimental platform for the LBE-water interaction was set up by the Innovative Nuclear System Laboratory in Shanghai Jiao Tong University. Then, the physical process of of LBE-water interaction was described on the basis of Fluent, coupling VOF model, Lee model, and SST k-ω model, and the numerical methodology with existing experimental data was validated. Thereafter a two-dimensional model of the experimental facility was established using ANSYS Fluent. Finally, multi-case simulations were conducted to simulate the overall process of the experiment and examine the effects of water inlet velocity, water inlet temperature, and initial LBE temperature.

The simulation results indicate that the jetting process can be divided into three stages and LBE solidification is avoided under the designed conditions. The minimum LBE temperature decreases with lower water inlet temperatures or higher inlet velocities. Concurrently, the maximum void penetration depth increases with elevated water inlet temperatures and velocities.

The results of this study provide a valuable reference for future experimental studies.

Heat pipes, as highly efficient heat transfer components that combine evaporation and condensation, are widely used in fields such as nuclear energy and aerospace. If geyser boiling occurs in a heat pipe, it will cause temperature fluctuations, thereby affecting the safety of the entire heat pipe stack.

This study aims to analyze the heat transfer characteristics of geyser boiling in high-temperature sodium heat pipes.

Firstly, an experimental platform for high-temperature sodium heat pipe heating was established. Then, the heat transfer characteristics of the evaporation section of a heat pipe using liquid metal sodium as the working fluid were studied at different liquid level depths and various mesh sizes, and the temperature and pressure parameters of the sodium heat pipes under different power conditions were obtained. Subsequently, the variation pattern of the geyser boiling oscillation period with changes in heating power and the trends in the heat transfer coefficient of the evaporation section with variations in liquid pool depth and mesh count were summarized. Finally, based on the experimental data, a model for the heat transfer coefficient of the evaporation section of sodium heat pipe in single-phase convection and geyser boiling regions was proposed.

Experimental results show that the temperature oscillation period is shortened with the increase of heating power. At the end of the heat pipe startup phase, the oscillation amplitude significantly decreases. The new evaporation section heat transfer model shows a maximum error of 21% in the single-phase convection zone and a maximum error of 39% in the intermittent boiling zone.

The results indicate that, within a certain range, the higher the filling ratio and the higher the mesh count of the wire mesh, the better the heat transfer performance of the heat pipe. Additionally, when the heat pipe experiences geyser boiling, its heat transfer performance is significantly lower than that during normal operation.

Mixing vanes can enhance the critical heat flux of fuel assemblies by generating vortices. Current studies primarily focus on the optimized design of traditional mixing vanes made of zirconium alloy and does not take into account the impact of mixing vanes on fretting wear of fuel rods.

This study aims to propose a novel type of mixing vane made of shape memory alloys to address the micro motion abrasion problem of fuel rods.

The two-way fluid-structure-thermal coupling analysis was employed to simulate the flow field distribution, pressure drop loss and fuel rod stress under a new type of mixing vane. Then, a nonlinear vibration model of fuel rod force with mixing vane made of shape memory alloys was established. Finally, a comparative analysis was conducted on the impact of different mixing vanes on the fretting wear power between fuel rods and the spacer grids.

The results indicate that shape memory alloys mixing vanes experience a similar pressure loss compared to traditional mixing vanes; the enhanced heat transfer effect increases with the maximum bending angle of the mixing vanes. Simultaneously, the fretting wear power between fuel rods and the spacer grids increases with the bending angle of the mixing vanes.

Shape memory alloys mixing vanes do not generate additional pressure loss while strengthening heat transfer between fuel rods and coolant.

The mixing vane plays an important role in reducing the hot-spot factor of the core, and the current studies are mostly aimed at analyzing the heat transfer performance, flow characteristics, and mixing performance under different mixing wing types and deflection angles. There are fewer studies on the correlation and quantitative effects of the fine structure of the mixing wing on the flow field.

This study aims to gain a deeper understanding of the impact of mixing vane structure characteristics on the thermal hydraulic performance of the reactor core, and analyze the correlation between mixing vane structure and flow fields.

Firstly, the parameterized and automated construction of the split vane structure was realized through the geometric automated configuration and calculation technology based on computational fluid dynamics (CFD) calculations. Secondly, through the orthogonal design of the split vane structure parameters and the analysis of the simulation results, the influence of the split vane structure on the thermal parameters such as the flow field pressure drop and cross-flow velocity was clarified. Simultaneously, the ANOVA (Analysis of Variance) method was used to compare the importance of different stirred wing parameters. Finally, the optimal mixing vane structure was obtained by direct analysis and its flow field characteristics were calculated. The flow field downstream of the churning wing was further calculated and analyzed.

Under the geometric structure of split mixing vane adopted in this article, the maximum difference in outlet pressure of different churning wings is 1.1 kPa, which is 41% of the average pressure drop in the whole computational fluid domain, and the maximum difference in cross-flow velocity under different churning wings is 1.1 m·s^-1, with the maximum cross-flow velocity being 173% of the average cross-flow velocity. The angle of the mixing vane is strongly correlated with the flow field that has the greatest impact on the mixing effect, followed by the shape and length of the mixing vane. The setting of the thermal boundary conditions has less influence on the flow field results with the optimal design of churning wing.

The method proposed in this provides a design basis for subsequent research and engineering application of the mixing wing structures.

Pebble Bed High Temperature Gas-cooled Reactor (PB-HTGR) is very different from other type of reactor in terms of its geometric structure, neutron characteristics, and mode of operation. Thus, it is imperative to develop a specialized analysis and calculation code for the PB-HTGR. A neutronics calculation module of the neutronics and thermal hydraulic calculation program suitable for PB-HTGR, named as NECP-Panda, has been independently developed by the Nuclear Engineering Computational Physics (NECP) Laboratory of Xi'an Jiaotong University.

This study aims to explore how the neutronics calculation module in NECP-Panda is achieved to improve the precision of core physics calculation of the PB-HTGR.

In the neutronics calculation, NECP-Panda adopted the two-step method. The first step was based on Monte Carlo method to calculate the component homogenized group constants while the homogenization of the pebble bed was performed using collision probability equations in the second step, and the whole-core diffusion calculation was subsequently completed using the three-dimensional cylindrical geometric Nodal Expansion Method (NEM). In order to accurately account for the influence of neutron leakage effect on the group constants of the model region, the diffusion calculation and neutron leakage correction were iterated until the group constants of the region converged. In addition, the neutron streaming effect of the porous structures was corrected in the iteration, and the cavity at the top of pebble bed was treated specially in the diffusion calculation. Finally, the NECP-Panda was verified by both the simplified mixed pebble bed reactor and the High Temperature Reactor Pebble-bed Module (HTR-PM).

The numerical results show that the eigenvalue calculation of the simplified mixed pebble bed reactor, calculated by NECP-Panda, is close to the Monte Carlo continuous energy result. The calculated HTR-PM critical loading height of the HTR-PM is highly consistent with the results of Monte Carlo continuous energy calculation, and the absorber value is also in good agreement.

Verification results in this study demonstrate that NECP-Panda possesses exceptional computational power and accuracy for the neutronics calculation of the PB-HTGR, establishing a solid foundation for the development of subsequent modules.

There is a large pressure difference and temperature difference on both sides of the heat transfer tube of the lead-bismuth reactor steam generator, and the lead-bismuth coolant has a corrosive effect on the heat transfer tube, there is a possibility of rupture in long-term operation.

This study aims to reveal the mechanism of pressure pulse generation in the steam generator tube rupture (SGTR) of lead-bismuth reactor, obtain the dynamic distribution of lead-bismuth, water and vapor components, and the pressure and temperature fields.

Firstly, based on the Computational Fluid Dynamics (CFD) method, a numerical simulation was carried out on the process of high-pressure water jet injection into a high-temperature lead-bismuth molten pool by coupling the Volume of Fluid (VOF) model, the Realizable k-ε model, and the Lee phase change model. Then, high pressure water jet injection of liquid lead bismuth experiment was conducted on the basis of LIFUS 5 platform to verify simulation results.

The results show that the simulated pressure and temperature changes are in good agreement with the experimental results, the main reason for the increase in pressure after high-pressure water injection is the large amount of vapor generated by depressurization and heating evaporation. The pressure peak detected at the position of x/d=1 on the axial centerline is the highest, which is 0.2 MPa, the farther away from the injection port, the smaller the detected pressure peak is, at x/d=20, no obvious pressure peak can be detected. During the vapor migration process, a K-H unstable vortex appeares at the interface between lead-bismuth and vapor, and the wake entrained and entrained part of the lead-bismuth, causing the vapor pockets to fragment into multiple vapor blocks.

The model proposed in this study has high reliability, and the research results can provide technical support for the safety design of lead-bismuth reactors.

Space radiation is one of the main factors that cause damage to living organisms and threaten the health of astronauts during long-term manned spaceflight. Therefore, space radiation risk assessment is an important issue in astronaut radiation risk warning and protection in manned spaceflight engineering.

This study aims to evaluate the biological effects of space radiation environment by simulating the radiation-induced DNA damage process using Monte Carlo method to digitize the damage yield at the cellular level.

Firstly, based on the main radiation sources in the space environment, five energy points with intervals of 10~10⁵ MeV for monoenergetic protons, helium ions, carbon ions, oxygen ions, silicon ions, and iron ions were set for the Monte Carlo damage simulation program (MCDS) applied to the calculation of DNA damage induced by high-energy protons and heavy ions in space. Simultaneously, typical solar proton event, as well as the main spectra in galactic cosmic rays during solar minimum and maximum, were selected as radiation sources to simulate the yields of DNA double strand breaks (DSBs), single strand breaks (SSBs), and other damages. Then, the effects of hypoxic and oxygen enriched cellular environments on damage yields and relative biological effectiveness were analyzed.

Simulation results of single energy radiation show that the number of SSBs gradually increases whilst the number of DSBs gradually decreases with the increase of energy. When the cell oxygen concentration is only 2%, the yields of DSBs caused by 10³ MeV protons, helium ions, carbon ions, and oxygen ions are reduced by 14.23%, 15.8%, 14.84%, and 12.08%, respectively, compared to the results under normoxic environment. The percentage reduction of silicon ions and iron ions can be ignored. Among the six types of monoenergetic space radiation particles, the relative biological effectiveness of silicon ions and iron ions with higher atomic numbers are more significantly affected by oxygen concentration. The results of DNA damage induced by proton spectrum during solar maximum and minimum show that the production of SSBs induced by proton spectrum during solar maximum is increased whilst the yield of DSBs is decreased when compared with that in solar minimum. For typical solar proton events, the yield of DNA damage is higher than that of galactic cosmic rays, with relative biological effect factors of 1.75 and 1.84 under 21% and 2% oxygen concentration, respectively.

This study uses a Monte Carlo damage model to evaluate the radiation effects of high-energy radiation particles in space at the cellular level. This model can be applied to quick prediction of the relative biological effects under different radiation, which is conducive to the development of radiation dosimetry and the establishment of a better space radiation dose monitoring model.

Rapid radionuclide identification is a crucial step in preventing the loss, smuggling, terrorist attacks, and radioactive contamination involving hazardous materials. Most current identification methods rely on gamma spectra as the primary analytical tool. However, due to limitations in spectral statistics, these methods require extended processing times to giving results, making them slow, less accurate, and poorly generalized for low-count-rate applications. Emerging radionuclide identification methods now utilize nuclear pulse peak sequence for analysis. However, these methods often fail to fully capture the features of nuclear pulse peak sequence, which limits the identification accuracy.

This study aims to propose a novel radionuclide identification method to overcome the limitations of spectral statistics and enhance the speed and performance of radionuclide identification.

A two-dimensional convolutional neural network (2D-CNN) utilizing nuclear pulse peak sequences was employed in this study. Firstly, four radioactive sources (¹³⁷Cs, ⁶⁰Co, ¹⁵⁵Eu and ²²Na) were used to collect low-count-rate nuclear pulse peak sequences for each single source, mixed sources and environmental backgrounds at varying source distances using a NaI(Tl) detector in the laboratory. Then, the collected sequences were preprocessed through fixed-length segmentation, min-max normalization, and two-dimensional matrix mapping to generate multiple nuclear pulse peak sequence datasets with different matrix sizes. Subsequently, a 2D-CNN model was developed to optimize the convolution kernel size and padding method using 10-fold hierarchical cross-validation to enhance feature extraction from nuclear pulse peak matrices. Finally, radionuclide identification capabilities of the model were tested on datasets with four simple and easily distinguishable sequences, five-category sequences, and eight complex-category sequences, and its performance was compared against three other methods: BPNN+PCA (Back Propagation Neural Network + Principal Component Analysis), SVM+PCA (Support Vector Machine + Principal Component Analysis) and 2D-CNN+spectrum.

The 2D-CNN radionuclide identification results show that with only 300 nuclear pulse sequence points, it achieves an accuracy of 99.61% on four easily distinguishable sequence sets. For five category sequence sets, an accuracy of over 95% is achieved with just 400 pulse sequence points. Moreover, for eight complex category sequence sets, a stable recognition accuracy is attained with 400 pulse sequence points. Additionally, comparative experiments with different models indicate that the 2D-CNN achieves accuracies of 100%, 98.61% and 84.45% for classifying four, five and eight category sequence sets, respectively. This performance significantly surpasses that of the BPNN+PCA, SVM+PCA, and 2D-CNN+gamma spectrum methods, and it also outperforms these models in single-source generalization.

The 2D-CNN model proposed in this study demonstrates feasibility in automatically extracting features from fixed-length nuclear pulse peak sequences. It effectively extracts pulse sequence features within a 40 cm detection range and performs rapid radionuclide identification. This method exhibits advantages in both accuracy and generalization, making it suitable for rapid radionuclide identification tasks with low count rates.

The Dynamics Line (D-Line) at Shanghai Synchrotron Radiation Facility (SSRF) is the first beamline in the world that combines synchrotron radiation infrared spectroscopy (SR-IR) with energy dispersive X-ray absorption spectroscopy (ED-XAS) to simultaneously detect the dynamic changes of the atomic, electronic and molecular structures of matter, which has important scientific value for the study of the structure of complex materials. Unlike conventional scanning X-ray absorption spectroscopy (XAS), ED-XAS technique uses a position-sensitive detector to obtain data files in image format, and the intensities of incident X-ray beam (I₀) and exit X-ray beam (I₁) after sample absorption are not collected simultaneously, ED-XAS spectrum cannot be observed in real time.

This study aims to develop a set of fast data acquisition and processing system for image format based on the requirements of ED-XAS experiments in D-Line.

Firstly, an object-oriented application programming interface (API) was developed using Python language, xiAPI Python interface, to access the XIMEA detector and obtain NumPy array format of I₀, I₁ and the intensity of detector background signal (I_dark). Then XAFS spectrum was calculated using the absorption coefficient formula, and drawn through matplotlib library. Finally, a user-friendly operating interface was developed using Qt Designer to show the real-time XAFS spectrum.

The results show that the connection with the detector in python language and the python third library This rapid data acquisition and processing system written by Python can quickly obtain the ED-XAS spectrum, it has been put into operation at ED-XAS station, providing an important analytical tool for the finding of rapid structural change and greatly improves the experimental efficiency.

Extreme ultraviolet (EUV) lithography is a critical technology for advanced semiconductor manufacturing that requires nearly defect-free EUV masks, necessitating high-resolution actinic (at-wavelength) imaging analysis for mask defect inspection.

This study aims to explore the potential for achieving higher resolution in actinic mask review by developing an elliptical zone plate design with anisotropic numerical aperture.

First, a simulation platform was established based on the EUV light generated by undulator equipment at the Shanghai Synchrotron Radiation Facility (SSRF). Second, simulations based on partial coherent light imaging modelwere performed to evaluate the imaging performance of three different collimator configurations under Fourier-synthesis illumination conditions. Finally, an elliptical off-axis zone plate with anisotropic numerical aperture was designed and optimized through systematic computational studies.

The simulation results demonstrate that the elliptical zone plate design achieves a numerical aperture of 4×NA=1.15 in the horizontal direction, significantly higher than the conventional circular zone plate's 4×NA=0.625. Under extreme dipole illumination conditions, a theoretical resolution of 12 nm half-pitch in the horizontal direction is achieved while maintaining 22 nm resolution in the vertical direction. The anisotropic design effectively overcame the reflectivity limitations of multilayer mirrors at large incident angles (<19°).

The proposed elliptical zone plate design with anisotropic numerical aperture in this study improves the resolution limit by 45.5% compared to conventional circular designs, achieving a 12 nm half-pitch resolution that surpasses the current international benchmark of 22 nm. This advancement provides a promising pathway for next-generation high-resolution EUV mask defect review systems.