摘要：Evaluating the comprehensive characteristics of extreme ultraviolet (EUV) photoresists is crucial for their application in EUV lithography, a key process in modern technology. This paper highlights the capabilities of the Shanghai Synchrotron Radiation Facility (SSRF) 08U1B beamline in advancing this field. Specifically, it demonstrates how this beamline can create fringe patterns with a 15-nm half-pitch (HP) on a resist using synchrotron-based EUV lithography (EUV-IL). This achievement is vital for evaluating EUV photoresists at the advanced 5-nm node. We provide a detailed introduction to the methods and experimental setup used at the SSRF 08U1B beamline to assess an EUV photoresist. A significant part of this research involved the fabrication of high-resolution hydrogen silsesquioxane (HSQ) mask gratings. These gratings, with an aspect ratio of approximately 3, were created using electron beam lithography (EBL) on an innovative mask framework. This framework was crucial in eliminating the impact of zeroth-order light on interference patterns. The proposed framework offers a new approach to mask fabrication, particularly beneficial for achromatic Talbot lithography and multicoherent-beam interference applications.
摘要：Full-field transmission X-ray microscopy (TXM) is a powerful nondestructive three-dimensional (3D) imaging method with a nanoscale spatial resolution that has been used in most synchrotron facilities worldwide. An in-house-designed TXM system was constructed at the BL18B 3D Nanoimaging beamline at the Shanghai Synchrotron Radiation Facility. The beamline operates from 5 to 14 keV and enables 20 nm spatial resolution imaging. The characterization details of the beamline are described in this paper. The performances in terms of spatial resolution, nano-CT, and nano-spectral imaging of the TXM beamline are also presented in this article.
摘要：Objective: The increasing incidence of breast cancer among Chinese women has necessitated the utilization of breast X-ray screening, which carries radiation risk. This work aims to provide a dosimetry protocol for the Chinese female population, to replace the traditional standard that utilize simplified breast models, for the accurate estimation of patients’ mean glandular dose undergoing digital breast tomosynthesis (DBT).
Approach: We have constructed the first set of Chinese female detailed breast models with their representative breast parameters. Considering the backscatter radiation and computational efficiency, we improved the combination of these models and the Chinese reference adult female whole-body voxel phantom. The image acquisition for four commercial DBT systems, which are widely employed in China, were simulated using the Monte Carlo method to obtain the normalized glandular dose coefficients of DBT (D_gN^DBT) and glandular depth dose (Dgdepz ) for different breast characteristics and X-ray spectra.
Main results: We calculated a series of D_gN^DBT for breasts with different percentage mass glandularity (5%, 25%, 50%, 75%, and 100%) and compressed breast thicknesses (2cm, 3cm, 4cm, 5cm, 6cm, 7cm), at various tube potentials (25kV, 28kV, 30kV, 32kV, 35kV, and 49kV) and target/filter combinations (W/Rh, W/Al, Mo/Mo, Rh/Rh, Rh/Ag). The parameter dependence of breast characteristics and beam conditions on D_gN^DBT of detailed breast models were investigated. The D_gN^DBT results were 14.6% - 51.0% lower than those of the traditional dosimetry standard in China. The difference in D_gN^DBT was mainly due to the decrease in the depth of the main energy deposition area caused by glandular distribution along the depth direction.
Significance: The results obtained in this work could be employed for the improvement of breast dosimetry in China, and provide more detailed information about risk assessment undergoing DBT.
摘要：Accurate measurements of the radon exhalation rate helps identify and evaluate radon risk regions in the environment. Among these measurement methods, the closed-loop method is frequently used. However, traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation chamber. The CFD-based technique was applied to predict the radon concentration distribution in a limited space, allowing radon accumulation and exhalation inside the chamber intuitively and visually. In this study, three radon exhalation rates were defined and two structural ventilation tubes were designed for the chamber. The consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was verified. The effects of the vent tube structure and flow rate on the radon uniformity in the chamber; permeability, insertion depth, and flow rate on the radon exhalation rate; and the effective diffusion coefficient on back diffusion were investigated. Based on the results, increasing the insertion depth from 1 to 5 cm decreased the effective decay constant by 19.55%, whereas the curve-fitted radon exhalation rate decreased (lower than the initial value) as the deviation from the initial value increased by approximately 7%. Increasing the effective diffusion coefficient from 2.77×10-7 to 7.77×10-6 m2 s-1 made the deviation expand from 2.14% to 15.96%. The conclusion is that an increased insertion depth helps reduce leakage in the chamber, subject to notable back-diffusion, and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion effect. The CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and, thus, the accurate measurement of the radon exhalation rate.
摘要：采用磁过滤阴极真空弧（FCVA）技术，结合交流碳弧（ACCA）技术和松弛技术，制备了~5 μg/cm2的自支撑类金刚石碳（DLC）剥离膜。通过XP2U电子天平、扫描电子显微镜（SEM）、拉曼（Raman）谱仪和X光电子谱（XPS）仪测试分析DLC膜的均匀性和微观结构，结果显示制备的DLC膜表面光滑、基本不含液滴、为典型的非晶DLC膜、sp3杂化键超过70%，Φ100 mm的范围的DLC膜最大不均匀性为8.82%。通过北京HI-13串列加速器提供的系列重离子束测试研究DLC剥离膜的寿命。结果显示，松弛后的DLC剥离膜寿命约为松驰前的3倍；对于63Cu-和197Au-离子束（加速电压~9 Mv、低能端流强~1 μA），DLC剥离膜寿命分别为碳弧碳剥离膜寿命的4倍和13倍；对于107Ag-、70Ge-、48Ti-、28Si-和127I-离子束，DLC剥离膜寿命为碳弧碳剥离膜寿命的2.6～10倍，并且离子越重、束流越强，DLC剥离膜的寿命对比碳弧碳剥离膜寿命的优势就越大；DLC剥离膜寿命与基衬偏压有一定关系，目前的测试结果显示，随基衬偏压的加大，剥离膜寿命呈现先升高后降低的大概趋势，-400 V左右的基衬偏压下DLC剥离膜寿命最长。
摘要：加速器中利用荧光靶系统测量束流横向剖面，为进一步提高系统测量的准确度，本文提出了一种利用简化快速行进算法（Fast Matching Method，FMM）填充荧光靶标定线的方法，使填充后的荧光靶图像更真实地反映束流剖面信息。论文首先利用Matlab生成模拟荧光靶图像，对比分析了算法处理前后的模拟图像束流剖面参数，仿真结果表明经过处理后的模拟图像，其结构相似性（Structural Similarity Index measure，SSIM）更接近1、均方误差（Mean Square Error，MSE）更小。最后，利用医用重离子加速器HIMM（Heavy Ion Medical Machine）现场采集的荧光靶图像进行验证。结果表明，HIMM现场采集的图像经处理后，剖面测量结果接近评估值。本研究结果为后续束流横向剖面参数算法的FPGA算法加速提供了依据。
摘要：A new measurement method for the spatial distribution of neutron beam flux in boron neutron capture therapy (BNCT) is being developed based on the two-dimensional Micromegas detector. To address the issue of long processing time in traditional offline position reconstruction methods, this paper proposes an FPGA-based online position reconstruction method, grounded in the micro time projection chamber principle. This method encapsulates key technical aspects: self-adaptive serial link technique built upon the dynamical adjustment of delay chain length, fast sorting and coordinate matching technique based on the mapping between signal timestamps and random access memory (RAM) addresses, and precise start point merging technique utilizing a circular combined RAM. The performance test of the self-adaptive serial link shows the bit error rate of the link is better than 10^-12 at a confidence level of 99%, ensuring reliable data transmission. The combined experiment of the readout electronics and the Micromegas detector shows a spatial resolution of approximately 1.4 mm, surpassing the current method's resolution level of 5 mm. The beam experiment confirms that the readout electronics system can obtain the flux spatial distribution of neutron beam online, thus validating the feasibility of the position reconstruction method. The online position reconstruction method avoids traditional methods such as bubble sorting and traversal searching, simplifying the design of logic firmware and reducing the time complexity from O(n^2) to O(n). This study contributes to the advancement in measuring neutron beam flux for BNCT.
摘要：EPICS控制软件广泛应用于粒子加速器等大型科学实验装置。根据装置规模的不同，其EPICS PV的数量从几万到上百万不等，快速查询EPICS PV的相关信息，可提升加速器的运维效率。为此，设计和开发了EPICS PV信息平台，该平台支持在统一的用户界面中查询 PV列表、实时状态、历史数据、操作日志以及IOC状态、IOC网络信息，并将这些信息关联在一起，实现综合展示。平台的用户界面采用Web技术，服务端基于Node.js运行环境开发以及结合EPICS社区已有的软件模块，网络信息采集等周期执行的程序采用Python语言开发。目前，EPICS PV信息平台已应用于CSNS加速器，并在实际运维中发挥了重要作用。
摘要：HFRS (HIAF FRagment separator (HFRS) will be the radioactive secondary beam separation line on High-Intensity heavy-ion Accelerator Facility (HIAF) in China. Several TPC detectors, with high count rates, are planned for particle identification and beam monitoring at HFRS. This paper presents an event-driven internal memory and synchronous readout (EDIMS) prototype ASIC chip. The aim is to provide HFRS-TPC with high-precision time and charge measurements with high count rates and a large dynamic range. The first prototype EDIMS chip integrated 16 channels and is fabricated using a 0.18-um CMOS process. Each channel consists of a charge-sensitive amplifier, fast shaper, slow shaper, peak detect-and-hold circuit, discriminator with time-walk compensation, analog memory, and FIFO. The token ring is used for clock-synchronous readout. The chip is taped and tested.
摘要：HVE-400 ion implanter is special ion implantation equipment for semiconductor materials boron and phosphorus doping. The ion source and extraction deflection system are at high voltage platform, while the corresponding control system is at ground voltage position. The control signals and measurement signals of various parameters at the high-voltage end need to be transmitted between ground voltage and high voltage through optical fibers to isolate high voltage. Upgrading is carried out due to the aging of the optical fiber transmission control and monitoring system, which cannot work stably. The transformation replaces the original distributed single-point control method with an advanced distributed centralized control method, and integrates all control and monitoring functions into an industrial control computer for digital operation and display. In the computer software, two kinds of automatic calculation of ion mass number are designed. After upgrading, the implanter high-voltage platform control and monitoring system features digitalization, centralized control, high reliability, strong anti-interference, fast communication speed, and easy operation.
摘要：Iron is commonly used as a structural and shielding material in nuclear devices. The accuracy of its nuclear data is critical for the design of nuclear devices. The evaluation data of 56Fe isotopes in the latest version of the CENDL-3.2 library from China was significantly updated. This new data must be tested before it can be used. To test the reliability of this data and assess the shielding effect, a shielding benchmark experiment was conducted with natural Fe spherical samples using a pulsed deuterium- tritium neutron source at the China Institute of Atomic Energy (CIAE). The leakage neutron spectra from the natural spherical iron samples with different thicknesses (4.5, 7.5, and 12 cm) were measured between 0.8-16 MeV after interacting with 14 MeV neutrons using the time-of-flight method. The simulation results were obtained by Monte Carlo simulations by employing the Fe data from the CENDL-3.2, ENDF/B-VIII.0, and JEDNL-5.0 libraries. The measured and simulated leakage neutron spectra and penetration rates were compared, demonstrating that the CENDL-3.2 library performs sufficiently overall. The simulation results of the other two libraries were underestimated for scattering at the continuum energy level.
摘要：To explore the kinetic adsorption under continuous and nonequilibrium states, an integration of continuous measurement and adsorption platform kinetics method was proposed, which was initially called the ICM-AP kinetics method, and a corresponding kinetic adsorption experimental method was developed. Adsorption experiments of europium (Eu) on Ca-bentonite, Na-bentonite, and the D231 cation exchange resin were performed using the ICM-AP kinetics method and continuous measurements. Because the kinetic experimental results observed in this study were different from those of traditional batch adsorption data, pseudo-first-order or pseudo-second-order kinetic models were unsuitable for fitting the experimental data. Hence, a liquid membrane diffusion (LMD) model was developed based on the assumption of simultaneous adsorption/desorption to discuss the mechanism of kinetic adsorption. The kinetic adsorption mechanism was also studied by using XPS. The results indicated that the proposed adsorption model can fit the experimental data more suitably, and the adsorption/desorption behaviors of Eu on bentonite and the D231 resin were simultaneously observed, suggesting that the adsorption kinetics of Eu(Ⅲ) was mainly dominated by hydrated Eu (III) ions on the liquid membrane.
通过蒙特卡洛模拟方法，充分考虑了完全耦合的物理模型，我们成功将电子-空穴对产生率（G(x)）扩展到了3D结构中，使得高效设计和开发具有复杂3D结构的贝塔辐射伏特电池成为可能。研究结果表明，相较于传统的平面电池，我们提出的3D电池在最大输出功率密度方面表现卓越，达到了19.74 µW/cm2，相应的短路电流、开路电压和转换效率分别为8.57 µA/cm2、2.45 V和4.58%。
摘要：A fully digital data acquisition system based on a field-programmable gate array (FPGA) was developed for a CsI(Tl) array at the External Target Facility (ETF)in the Heavy Ion Research Facility in Lanzhou(HIRFL). To process the CsI(Tl) signals generated by γ-rays and light-charged ions, a scheme for digital pulse processing algorithms is proposed. Every step in the algorithms was benchmarked using standard γ and α sources. The scheme, which included a moving average filter, baseline restoration, leading-edge discrimination, moving window deconvolution and digital charge comparison was subsequently implemented on the FPGA. A good energy resolution of 5.7% for 1.33 MeV γ rays and excellent α-γ identification using the digital charge comparison method were achieved, which satisfies CsI(Tl) array performance requirements.