Proposal for a high brightness γ-ray source at the SXFEL

High brightness γ-rays produced by laser Compton scattering(LCS) are ideal probes for the study of nucleon and nuclear structure. We propose such a γ-ray source using the backscattering of a laser from the bright electron beam produced by the linac of the Shanghai Soft X-ray Free-electron Laser(SXFEL) test facility at the Shanghai Institute of Applied Physics(SINAP). The performance is optimized through theoretical analysis and benchmarked with 4D Monte-Carlo simulations. The peak brightness of the source is expected to be larger than2 × 1022photons/(mm2mrad2s 0.1%BW) and photon energy ranges from 3.7 Me V to 38.9 Me V. Its performance, compared to Extreme Light Infrastructure-Nuclear Physics(ELI-NP), and the Shanghai Laser-Electron Gamma-ray Source(SLEGS), is given. The potential for basic and applied research is also briefly outlined.

Studying a kind of portable ultra-bright microfocus x-ray source

This paper studies the properties of a kind of portable ultra-bright microfocus x-ray source with the Monte-Carlo method in detail. The new x-ray source consists of an electron-emission system, an electrostatic focusing system and a metal target. A crystal Lanthanum Hexaboride cathode, a Wehnelt grid and an extracted electrode compose the triode electrode electron-gun system. Two equal radius cylinder electrodes form the focusing system. The key factors determining the focus properties of the electron beam such as the ratio Dw/H, grid bias Vg, and the properties of the extracted electrode arc numerically studied. The calculated results reveal that when Dw/H, Vg, the length of the extracted electrode, and the distance between the grid and the extracted electrode equals 5, q）.6 kV, 10 mm, and 8 mm respectively, the electron beam focal spot can be concentrated down to 9 μm in radius and a reasonable focal length about 72.5 mm can be achieved, at the same time, the cathode emission currents can be as high as 30 mA.

Photo-transmutation based on resonance γ-ray source

High intensity γ-ray source can be obtained through resonance reaction induced by protons. In this work, the possibility of using such high intensity MeV-range γ-ray source to transmute nuclear waste is investigated through Mont Carlo simulation.197 Au(γ, n)196Au experiment is performed to obtain the transmutation rate and compared with the simulation result. If the current of the proton beam is 10 mA at the resonance energy of 441 keV, with the γ photons emitted from7 Li(p, γ)8 Be, then the corresponding transmutation yield for129I in 2π direction can reach 9.4 × 109 per hour. The result is compared with that of LCS γ-ray source.

9MeV,小于0.1mm微焦点X射线源验证实验

密度高、成像分辨率高、成像速度快的X射线数字成像检测需要高能微焦点大剂量X射线源,高品质电子源是实现这一X射线源的关键手段。基于中国工程物理研究院太赫兹自由电子激光的主加速器,验证了低发射度、低能散度的高亮度电子束实现高能微焦点的可行性,得到电子束半高全宽尺寸小于70μm的9 MeV微焦点,并初步开展成像实验,双丝像质计焦斑清晰分辨9D号丝,丝直径0.13 mm。

高功率固体激光和相关单元技术研究的新进展

对高功率固体激光和相关单元技术研究的新进展，如高功率二极管泵浦固体激光器，用于惯性约束聚变和惯性聚变能的二极管泵浦固体激光驱动器，ＴＷ和ＰＷ级高亮度源，以及板条固体激光放大器等研究的新进展作了评述和分析。

基于局部区域模式噪声的数字图像源辨识算法

数码相机的传感器模式噪声可以作为相机指纹实现数字图像源辨识。针对模式噪声的提取效果对图像内容有较大的依赖性,文章发现亮度高纹理简单的区域模式噪声质量较高。因此,首先根据图像的纹理和亮度设计一个评估函数,用该函数对测试图像每个块进行评估,选择出亮度高纹理简单的区域;最后利用选择区域的模式噪声,使用相关性检测器实现数字图像源辨识。实验证明了基于局部区域模式噪声的数字图像源辨识算法的有效性和优越性。

空间植物栽培用OLED平板光源的设计与实现

针对空间植物栽培对光照的需求,研制了一种高效、高亮度,能在特殊环境中长时间稳定工作的叠层OLED平板光源样机。测试结果表明,该平板光源在15 V电压的驱动下,发光亮度高达2198 cd/m2,在电流密度为25 m A/cm2条件下,达到最大发光效率46.5 lm/W。根据器件EL光谱分析可知,其发射光谱范围在400~830 nm之间,分别在475 nm、551 nm和612 nm处出现蓝、绿、红三原色的发射峰,红橙光和蓝紫光较饱和,适合作植物栽培光源。

铁电体阴极的实验研究

铁电体阴极是一种具有很大发展潜力的新型高亮度、高重复率、强流电子束源。电子发射的基本机制是利用铁电体中的快极化反转产生的极化值变化,其转换时间为纳秒量级,因此,重复率可达数百兆赫;最大电子发射密度为10^(14)/cm^2;发射电流的大小取决于样品上激励电压的上升时间;发射电子的最大能量决定于样品厚度,初步估算,在电流强度相同的情况下,铁电阴极的亮度可比激光照射的光阴极高4倍,与传统电子源相比,它具备许多特殊的优点,本文报导了E∥P和E⊥P两种实验模式,测得的最大发射电流密度分别为12A/cm^2和21A/cm^2。

采用高亮度LED背光源的液晶显示模块

介绍了一款高亮度LED背光源显示器前端模块,它是采用恒流源驱动的高亮度LED发光矩阵为背光源,取代了传统的CCFL背光源,文中对两种背光源的应用及性能进行了比较,介绍了NS公司的开关型的稳压器LM2733,芯片做为恒流源驱动芯片在显示模块中的使用方法,该模块采用单片机产生脉宽调制脉冲进行亮度调节,实现了相关画面的输出和控制。