中子照相数值模拟与实验的对比

 介绍了热中子照相的MCNP数值模拟方法，模拟了300＃反应堆Maxwell谱热中子束穿透样品射到转换屏的过程，给出了热中子对铝、铅、铁、铜的穿透能力，分析了引起模拟与实验结果不同的原因。通过模拟得到了清晰的图像，对比数值模拟与在300#反应堆中子照相装置上的实验结果，数值模拟结果图像与实验结果图像非常相似；散射中子对图像的影响也符合相同的规律，随着样品与转换屏之间的距离的增大，散射中子对结果图像的影响越来越小，当样品与转换屏之间的距离为样品尺寸的2倍时可以忽略散射中子的影响。     

Quasi-Elastic Scattering of 16C from 12C at 47.5 MeV/Nucleon

Differential cross sections for the quasi-elastic scattering of^16 C at 47.5 MeV/nucleon from ^12 C target are measured.Coupled-channels calculations are carried out and the optical potential parameters are obtained by fitting the experimental angular distribution.     

Au-Ag三角纳米环单层膜的原位转化制备及 SERS效应

利用模板牺牲氧化还原反应将自组装在基片上的三角板银纳米粒子(边长约为79.2 nm)与氯金酸溶液作用进而原位转化形成三角纳米环. 通过紫外-可见(UV-Vis)光谱实时监测基片上银三角板纳米粒子在反应不同阶段的消光特性; 扫描电子显微镜(SEM)显示了银三角板纳米粒子转化过程的形貌变化; 利用X射线光电子能谱(XPS)对其成分进行分析. 表征结果表明, 三角纳米环的成分为Au-Ag合金或复合物; 随着基片与氯金酸溶液作用时间的增加, 自组装膜的表面等离子体共振峰逐渐红移; Au-Ag三角环状纳米粒子的平均壁厚度从29.3 nm缩小至16.2 nm. 以4-巯基苯胺(4-ATP)为探针分子研究了该Au-Ag三角环状纳米粒子单层膜的表面增强拉曼(SERS)活性. 自组装单层膜基底的SERS信号随着Au-Ag三角纳米环平均壁厚度的增加逐渐增强.     

Z切石英单晶侧壁腐蚀形貌修平方法

石英单晶具有复杂的晶向,侧壁腐蚀形貌不规则。以制作规则的微惯性传感器关键结构单元—石英悬臂梁-质量块结构为研究目标,研究Z切石英单晶在氟化氢铵溶液中的侧壁腐蚀形貌演化规律具有重要意义。首先研究了侧向所露晶面的倾斜角度和腐蚀速率随方向角的变化,在此基础上研究了侧面晶棱随时间的演化规律。研究结果表明:侧向所露晶面的倾斜角度和腐蚀速率随方向角发生变化,在方向角50°~90°范围,双向腐蚀是侧向只出现一级晶棱,其它方向出现二级晶棱;侧面晶棱可通过长时间的腐蚀修平,修平时间随方向角发生变化。以石英悬臂梁-质量块结构为例,通过腐蚀7.5 h,获得了侧壁平整的石英悬臂梁-质量块结构,证明了该方法的适用性。该方法有助于在设计石英结构时能够考虑侧壁形貌对结构性能的影响,或利用侧壁形貌特点对结构进行设计。     

Developments of a 2D position sensitive neutron detector

China Spallation Neutron Source (CSNS), one project of the 12^th Five-Year-Plan scheme of China, is under construction in Guangdong province. Three neutron spectrometers will be installed during the first phase of the project, and two-dimensional position sensitive thermal neutron detectors are required. Before the construction of the neutron detectors, a prototype of a two-dimensional 200 mm×200 mm Multi-wire Proportional Chamber (MWPC) with Ar/CO₂ (90/10) flowing gas has been constructed. In 2009, the prototype was tested with the ⁵⁵Fe X-ray using part of the electronics, and performed well.     

中红外玻璃材料发展及前沿应用

中波红外玻璃综合了优良的透红外性能、大尺寸制备特性和低成本,是很多重要军用系统的关键窗口材料之一.红外玻璃的高性能、大尺寸化制备面临重要挑战,同时红外技术和光电对抗技术的发展对红外窗口的雷达隐身性能也提出了很高的要求.综述了国内外中红外玻璃研究发展现状,着重介绍了中国科学院上海光学精密机械研究所在红外玻璃及其高性能化研...     

Knockout reaction induced by ~6 He at 61.2 MeV/u

A knockout reaction induced by ⁶He at 61.2 MeV/u was carried out at the HIRFL-RIBLL radioactive beam line. The α core fragments at forward angles were detected in coincidence with the recoiled protons at large angles. From this coincident measurement the valence nucleon knockout mechanism and the core knockout mechanism can be separated according to the polar angle correlation between the core fragments and the recoiled protons. It is demonstrated that, when reconstructing the resonant state of a weakly bound nucleus, the contamination resulting from the core knockout mechanism should be eliminated in order to obtain the correct structure information.     

重离子治癌终端的束流强度及剂量监测系统

 为实现重离子肿瘤治疗临床实验中对照射束流状态的实时监测,研制了束流强度及剂量监测系统,包括积分电离室、后续电流频率转换电路及LabVIEW数据获取处理三部分。利用闪烁体探测器和标准剂量计测试了系统的线性响应和得到剂量的准确性,结果表明：系统在束流临床照射流强范围内的线性响应好于90%,其实时反馈的临床照射剂量偏差小于5%。同时束流强度及剂量监测系统与安全控制系统相结合,保证束流照射状态满足临床照射的安全要求。     

用于二维位敏闪烁体中子探测器的波移光纤性能研究

波移光纤是闪烁体中子探测器的重要组成部分,其性能参数——光衰减长度、光损失率和光吸收重发射效率等将直接影响探测器的性能。本研究利用一套光纤性能测试试验装置,系统地研究了BCF91A 型波移光纤的光传输性能。结果表明:BCF-91A 型波移光纤光衰减长度为(1485) cm,吸收重发射效率约为5.6%;当光纤转弯半径为20 mm,长度为1.1 m时,其性能可以满足闪烁体中子探测器要求;BCF-91A 型波移光纤是很好的光纤候选材料.The position-sensitive scintillator neutron detector (SSND) with high efficiency, high resolution and high n/ discriminate ability etc., is developed to replace the traditional 3He neutron detector. The wave-length shifting fibers (WLSF) are used in SSND. The performances of BCF-91A type WLSF, such as attenuation length, bend loss and lights transportation ability etc., are studied in this paper. The attenuation length is (1485) cm.The lights transportation ability is about 5.6%. When the length of WLSF is 1.1 m, the bend radius is 20 mm,the photon number N transferred by the fiber meet the demand of SSND. According to the result, BCF-91A type WLSF is a good candidate for SSND.     

Characteristics of a 4-fold segmented clover detectore

Four high-purity germanium 4-fold segmented Clover detectors have been