Fabrication of multi-scale structures with multiple X-ray masks and synchrotron hard X-ray irradiations

Synchrotron hard X-ray irradiation can be utilized in lithography processes to manufacture precise structures. Due to the difficulty of precise X-ray mask fabrication in hard X-ray lithography, this X-ray process has been used mainly to fabricate precise microstructures. In this study, a technology is proposed for fabricating novel multi-scale patterns that include submicron-scale structures using hard X-rays. The required X-ray masks for submicron-sized patterning are fabricated by a simple UV lithography process and sidewall metal deposition. Above all, thanks to the high penetration capability of hard X-rays with sub-nanometer wavelengths, it is possible to employ multiple masks to fabricate a variety of patterns. By combining each sub-micron X-ray mask with typical micro-sized X-ray masks, a unique X-ray lithography is performed, and various multi-scale structures are fabricated. The usefulness of the proposed technology is demonstrated by the realization of these structures.     

X-ray magnetooptics based on synchrotron radiation

The conditions for obtaining a maximum magnetic signal in different experiment geometries have been analyzed on the basis of the general theory of reflection from a layered anisotropic medium. It is shown that, in the equatorial geometry in Bragg reflections from a periodic structure with antiferromagnetic interlayer ordering, amplification of linear dichroism arises, which can be observed even in the grazing geometry.     

X-ray detectors based on epitaxial gallium arsenide

Two types of photovoltaic X-ray detectors based on intrinsic and chromium-compensated epitaxial gallium arsenide are studied. The amplitude spectra taken with different radioactive sources show that the efficiency of charge collection in these detectors is no higher than 60%. While in the detectors made from intrinsic epitaxial GaAs (a free electron concentration on the order of 10¹² cm^?3) incomplete charge collection is related to a nonuniform electric field generated by the space charge of deep levels, in the structures based on the chromium-compensated epitaxial material with specific resistance ρ ～ 10⁸ Ω cm, incomplete charge collection is caused by intense capture of holes. It is shown that, in the latter structures, the lifetime of nonequilibrium electrons is rather high and may reach 40 ns.     

X-ray diffraction filters based on track membranes

The principle of operation of X-ray filters made of polymer track membranes with through cylindrical pores is described. The relationship between the transmission of track membranes and the parameters of pores and optical constants of the polymer matrix is established. The way in which the interface roughness improves the spectral selectivity of diffraction filters is recognized.     

X-ray interferometer based on fresnel zone plates

A new type of X-ray interferometer based on three multilevel zone plates with common lens axis is suggested. Like to well-known triple Laue-case X-ray interferometer this interferometer does not impose strict requirements on the spatial and time coherence of the incident wave and therefore can be used with laboratory X-ray sources. The interferometer has advantages in the area of phase-contrast X-ray imaging connected with the image magnification.     

Features of the manufacture of deep X-ray lithography masks in the siberian synchrotron and terahertz radiation center

The development of a low-cost technology to manufacture high-contrast X-ray LIGA masks is topical because this technology is important for various applied research on microstructured products with minimum element sizes of 10–50 μm, such as microfluid analytical systems, selective waveguide mesh-based elements to control terahertz (THz) radiation, microshaped optical elements for the visible range, etc. Technological particularities of mask manufacture are considered. A method to check the quality of masks is presented. Test microproducts manufactured using the produced deep X-ray lithography masks are demonstrated.     

A cryptosystem based on deterministic phase masks and fractional Fourier transform deploying singular value decomposition

In this paper, an asymmetric cryptosystem has been proposed to enhance the security of DRPE. The traditional DRPE scheme is thus tweaked by using fractional Fourier transform (FrFT), a class of structured phase masks called as deterministic phase masks (DMKs) and deploying singular value decomposition (SVD). In specific, we propose to organise the encryption procedure by using two DMKs and FrFT, additionally deploying SVD. On the decryption front, the input image is recovered by utilising the inverse singular value decomposition (ISVD) and an angular portion of the deterministic phase masks. The use of FrFT for encryption and decryption would enhance the robustness of DRPE scheme. Deployment of SVD on our asymmetric cryptosystem provides three components for cipher image is yet another added feature that hardens the security of DRPE scheme. DMKs are formed by the deviation from conventional rectangular function and limited range values which delivers key components with reduced size, better performance and lower complexity. The capability study of defined method, includes analysis on SVD, histogram and correlation coefficient. Our system is subject to an occlusion attack and noise attack to evaluate its performance and reliability. Computational analysis outputs and security investigation are offered in aspect to determine the security potential of proposed system. Comparative results are shown for values of mean-square-error and peak-signal-to-noise ratio of DRPE schemes.     

New possibilities of X-ray nanocrystallography of biological macromolecules based on X-ray free-electron lasers

X-ray serial nanocrystallography is a new technique for determining the three-dimensional structure of biological macromolecules from data on the diffraction of ultrashort pulses generated by X-ray free-electron lasers. The maximum achievable resolution for a set of experimental data as a function of the sample sizes and parameters of the equipment is estimated based on simulations of the diffraction process with allowance for changes in the electronic structure of the atoms of the sample under the influence of X-rays. Estimates show that nanocrystallography greatly enhances the possibilities of X-ray analysis, reducing the requirements for the minimum permitted size of the crystals and enabling to explore poorly crystallizable molecular objects, such as many membrane proteins and complexes of macromolecules.     

基于超环面晶体的X射线成像诊断

设计了可用于X射线成像用的聚焦型超环面晶体谱仪,讨论了基于布拉格几何结构的超环面及球面弯曲晶体聚焦特性,给出了基于超环面晶体X射线2维单能成像的光源、晶体及探测器的最佳位置,在中国工程物理研究院激光聚变研究中心进行了X射线背光成像实验.利用超环面弯曲晶体作为成像器件,其弧矢及子午平面的曲率半径分别为290 mm及190...     

Compact X-ray radiograph based on a plasma gun

The results of the experiments on the formation of a plasma emitter with small spatial dimensions for pulsed radiography in the soft X-ray spectral range are presented. Emitting hot plasma was formed as a result of compression of the plasma jet by a current pulse with amplitude I _m = 215 kA and rise time T _fr = 200 ns. For the jet formation, we used a plasma gun based on the arc discharge (I _m = 8.5 kA and T _fr = 6 μs) initiated by breakdown over the surface of a dielectric in vacuum. The experiments were carried out with aluminum, tin, copper, and iron plasma jets. A single emitter, i.e., point Z-pinch (PZ-pinch), was formed when an interelectrode gap of a high current generator of 1.3–1.5 mm was used. The smallest spatial dimensions of the emitting region were obtained with the use of aluminum and tin. For a tin jet, the diameter of the emitting region was 7 ± 2 μm and its height was 17 ± 2 μm. The emission pulse duration at half-height was 2–3 ns. The total emission yield per pulse in the spectral range 1.56–1.90 keV was 30–50 mJ for the aluminum pinch and 10–30 mJ for the tin pinch. The developed method makes it possible to carry out radiographic examination of microobjects (including biological ones) 1–1000 μm in thickness, with spatial (10–20 μm) and time (2–3 ns) resolution.     

基于光子筛的软X光谱仪

 介绍了采用新型软X光谱学光子筛作为分光元件的软X光谱仪的原理和结构参数设计。新谱仪理论测量范围为100 eV~2 keV,光谱分辨力达0.35 nm。应用该谱仪在SILEX-Ⅰ装置上测量了飞秒激光与固体铜靶相互作用产生的X射线发射谱。实验结果表明,该谱仪主要性能指标达到设计要求,适合于激光与等离子体相互作用产生的软X射线研究。     

A note on grating based soft X-ray monochromators

A few facts related to the aberrations for toroidal and plane gratings are presented. Some design aspects of the plane grating-based monochromator devised by Petersen (1982) are discussed. We also point out that for a cylindrical grating astigmatic correction can be reduced and suggest that following Petersen’s scheme some improvements in the monochromator performance could be achieved with such a grating.     

基于X射线的空间语音通信系统

提出了栅控X射线源作为发射器和基于微通道板的X射线单光子探测器作为接收器的X射线通信方案. 搭建了基于X射线的空间语音通信系统, 详细介绍了信号调制发射器、基于微通道板的X射线单光子探测器及信号接收解调器的设计及工作原理. 报道了基于X射线的空间语音通信系统的初步实验结果, 实现了优于20 kbit/s的基于语音信号调制的X射线通信. 实验分析了在不同X射线强度、信号整形时间和阈值设置下通信性能影响, 得出了X射线发射功率限制X射线通信速率的结论, 提出了下一步提高X射线通信性能的改进方案. 关键词： X射线通信 X射线源 探测器     

基于光子筛的软X光谱仪

介绍了采用新型软X光谱学光子筛作为分光元件的软X光谱仪的原理和结构参数设计。新谱仪理论测量范围为100 eV~2 keV,光谱分辨力达0.35 nm。应用该谱仪在SILEX-Ⅰ装置上测量了飞秒激光与固体铜靶相互作用产生的X射线发射谱。实验结果表明,该谱仪主要性能指标达到设计要求,适合于激光与等离子体相互作用产生的软X射线研究。     

基于深度学习的铸件X射线图像分割研究

针对当前图像分割算法在实现工业铸件内部缺陷分割上精度低且算法不够轻量化的问题,提出一种基于改进DeepLabv3+的工业铸件内部缺陷检测算法Effi-DeepLab。该方法采用EfficientNet中的MBConv来代替原有的Xception模块进行特征提取,使特征提取网络更加高效与轻量化;针对工业铸件内部缺陷尺寸小的问题,重新设计空洞空间金字塔池化（ASPP）层中空洞卷积的扩张率,使得卷积块对小目标具有更高的鲁棒性;在解码端充分利用特征提取阶段的低阶语义信息进行多尺度特征融合,以提高小目标缺陷分割的精度。实验结果表明,在本文使用的汽车轮毂内部缺陷图像数据集中,Effi-DeepLab模型对缺陷的分割准确率和平均交并比（mIoU）分别为93.58%和89.39%,相比DeepLabv3+分别提升了2.65%和2.24%,具有更好的分割效果;此外,还通过实验验证了本文提出算法具有良好的泛化性。     

Optical color image encryption based on the wavelength multiplexing using cascaded phase-only masks in Fresnel transform domain

A novel technique, based on a modified Gerchberg–Saxton algorithm (MGSA) in the Fresnel-transform (FrT) domain, is proposed to encode a color image into three phase-only functions (POFs) for three separated channels: red (R), green (G), and blue (B). The decomposed three RBG channels can avoid the interference of crosstalks efficiently. In proposed decryption process, a color image can be promptly reconstructed by summing of the three decrypted RGB images after the created three POFs which are decrypted one by one. In this paper, all the created three POFs and the system parameters of FrT can be used as the keys for increasing security that are also demonstrated. The computer application simulations to the partial color encryption and decryption are given to validate the feasibility of the proposed scheme.     

Soft X-ray point source based on a gas pinch

JETP Letters - The results of a study of a radiating Z-pinch with a profiled initial gas-density distribution over the z axis are presented. The gas distribution with the density maximum and...     

基于Bohr-Sommerfeld量子理论的X射线光谱分析

基于Bohr-Sommerfeld量子理论,研究了特征X射线的产生机理,导出了一个按原子序数来计算特征X射线波长的公式.同时对计算推导的波长值做了系统的误差分析,得到了相对误差的规律.结果表明,计算推导的波长值与实验得到的波长值非常接近,并且在实际应用中该公式也更为简便. 关键词： Bohr-Sommerfeld量子理论 特征X射线 波长 误差分析     

An X-ray imaging detector based on pixel structured scintillator

An X-ray imaging detector consisting of a silicon charge coupled device (CCD) and pixel structured scintillator was developed to improve spatial resolution. The pixelated structure reduces spreading of scintillation light through the scintillator by providing air gap between scintillator pixels, and increased spatial resolution by reducing the cross-talk between CCD pixels. The modulation transfer functions (MTF) of the non-pixelated and pixilated scintillator detector were compared. The improvement in spatial resolution was evaluated by both computational simulation and experimental measurement of MTF; both results showed coincidence.