高分辨micro-SPECT成像系统针孔准直器的优化设计

为了最大限度地减少γ射线在针孔准直器上的透射和散射效应,采用蒙特卡罗方法对单光子发射计算机断层(SPECT)成像系统使用的针孔准直器进行优化.模拟计算结果与实验测试得到的系统灵敏度和空间分辨率曲线相符,达到了高分辨小动物成像的要求.     

应用于高能伽马射线源图像诊断的厚针孔设计

在伽马射线辐射源图像诊断中,一般使用厚针孔将辐射源产生的伽马射线图像成像在射线图像探测器上.由于射线具有较强的穿透效应,针孔具有较厚的厚度,厚针孔成像系统的空间分辨、能通量、有效视场等测试要求相互制约,必须给出最优的厚针孔结构设计.根据厚针孔成像系统的特点,模拟计算厚针孔成像系统的基本过程.计算结果表明,在最优厚针孔结...     

M310机组共用辅助蒸汽系统STR设计与研究

辅助蒸汽系统作为M310堆型核电站的辅助系统,在核电站启动、运行和停运期间为相关用户提供低压蒸汽.STR系统作为辅助蒸汽系统一个子系统,在电站正常运行期间,通过主蒸汽对另外一侧的水加热来产生辅助蒸汽,并确保辅助蒸汽和主蒸汽隔离.由于存在经济性和辐射防护等问题,是否设置STR系统一直存在争议.据此,本文给出了4台M310机组辅助蒸汽系统设计方案之一,即4台机组共用1＆2机组STR系统,并对该方案进行了详细分析和研究.     

X-ray CCD相机在杆箍缩二极管X射线焦斑诊断中的应用

针孔成像法是诊断杆箍缩二极管X射线焦斑的常用方法。本文建立基于增感屏、光锥耦合、CCD相机的X-ray CCD相机系统,取代针孔成像法中基于闪烁体、物镜、CCD相机的图像获取系统,提高了诊断系统的紧凑性。对所建立的X-ray CCD相机系统的空间分辨能力进行了测试,系统的空间分辨能力受增感屏限制,使用铅制分辨卡测得系统的空间分辨率为5lp/mm,使用刀口法测得调制传递函数为0.5时的频率为1.5lp/mm。测试结果表明,在针孔成像倍率为0.5时,可满足1.5 mm左右的X射线焦斑诊断的需要。并开展了杆箍缩二极管侧面焦斑诊断实验,获得了侧面焦斑图像,且进行了图像复原处理。     

产品设计中的计算机辅助公差分析

介绍了传统公差设计方法的不足和计算机辅助公差设计(CAT)方法的优点.比较了极值法、统计法和Monte-Carlo模拟法3种公差分析方法的优缺点;给出了进行计算机辅助公差分析的基本流程和相关注意事项.以某反应堆压力容器简体、吊篮简体、压紧简体及支承板为研究对象,根据其三维设计模型,使用CAT软件VSA建立公差仿真模型,进行公差仿真分析,并根据分析结果对公差分配方案进行优化.     

X射线源针孔成像方法可行性研究

为检验利用针孔成像对X射线源进行研究的可行性，对X射线针孔成像系统进行优化设计，搭建了1套X射线源针孔成像装置。从理论上对X射线源的位置和强度发生变化时图像的相应变化进行了计算和预估，并用实验加以验证。结果表明，像斑中心位置的移动和像斑灰度值的变化分别与X射线源位置和强度的变化在一定范围内存在线性关系，由此证明了利用针孔成像对X射线源进行空间定位及定量研究的可行性。本文结果对X射线源针孔成像的系统设计具有参考意义。     

γ针孔照相测量放射性污染分布

介绍了一种测量设备γ放射性表面污染的新方法。利用γ射线的直线传播和与物质相互作用的特性，采用针孔成像原理，以＾２３８Ｕ作为针孔材料，通过模拟计算得到针孔的设计参数，并据此制作一视场角为６０°的针孔相机。利用此相机分别对γ污染源和污染设备成像，经计算机处理，将此二幅图像叠加起来，可以清楚地知识污染源在设备上的位置及其在相机处产生的剂量水平。该方法具有直观、清晰、工作人员受辐射剂量少的优点，测量结果可     

高分辨率小动物SPECT成像系统的设计与性能评估

为实现低成本、高分辨率的小动物单光子发射断层成像(SPECT),设计了一种基于临床探测器和针孔准直器的小动物SPECT成像系统。综合考虑视野尺寸、空间分辨率和绝对探测效率等指标,分别给出了单针孔和七针孔准直器的两种最优化设计方案,并通过对比两种设计方案在全视野范围内的平均空间分辨率和探测效率,对成像性能进行了评估。结果表明,与单孔准直器相比采用七针孔准直器设计可同时获得更高的空间分辨率和探测效率。经蒙特卡罗模拟成像实验验证,该七针孔准直器在临床探测器上可达0.5mm级的超高空间分辨率,且成本远低于采用专用探测器的现有小动物SPECT系统。     

大动态针孔相机在ICF激光焦斑诊断中的应用

在神光Ⅲ原型装置上,作为主要诊断设备的X光针孔相机发挥了重要的作用.论文提出了一种基于4×4的多针孔阵列板,该针孔阵列板具有测量动态范围大、视场大、瞄准精度要求降低、更换滤片次数减少等特点.同时在神光Ⅲ原型实验中使得针孔相机的实验数据获取率得到提高.     

X射线源针孔成像系统优化设计研究

为提高X射线源针孔成像系统的性能,对成像能区为10~100 keV的X射线源针孔成像系统进行了优化设计研究。综合应用了理论分析和蒙特卡罗模拟的方法,首先根据X射线波长、准直器角响应和X射线穿透效应对针孔成像的不同影响结果设计了可有效控制成像分辨率和成像面积变化的船底型准直器,随后用蒙特卡罗方法对使用该准直器的针孔成像系统进行了模拟验证。结果表明,对于100 keV以下的X射线,经船底型准直器后,成像的空间分辨率和亮斑亮度较稳定,能得到相对准确的X射线源定位、定量信息。     

Development of SUPKIT-II: Computer Aided Fault Tree Analysis System

A computer aided reliability analysis system, in which an interactive graphic terminal can be used, to construct, modify, analyze, and store fault trees is developed. The system, SUPKIT-n, a computer aided fault tree analysis system has functions for fault tree automated construction (PREP) and fault tree graphics (GRAPH). The former automatically generates a fault tree by a hierachical structure based on system configuration and specifications, and/or from failure information, while the latter indicates, modifies, and evaluates the fault tree through CAD/CAM terminals. Therefore, PREP decreases man-hours and mistake occurrences in constructing fault trees and GRAPH enables users to evaluate system reliability and to compare system design plans easily and quickly.     

Space-resolved vacuum-ultraviolet spectroscopy for measuring impurity emission from divertor region of EAST tokamak

The measurement of impurity distribution in the divertor region of tokamaks is key to studying edge impurity transport. Therefore, a space-resolved vacuum-ultraviolet (VUV) spectrometer is designed to measure impurity emission in the divertor region on EAST. For good spectral resolution, an eagle-type VUV spectrometer with 1 m long focal length with spherical holograph grating is used in the system. For light collection, a collimating mirror is installed between the EAST plasma and the VUV spectrometer to extend the observing range to cover the upper divertor region. Two types of detectors, i.e. a back-illuminated charge-coupled device detector and a photomultiplier-tube detector, are adopted for the spectral measurement and high-frequency intensity measurement for feedback control, respectively. The angle between the entrance and exit optical axis is fixed at 15°. The detector can be moved along the exit axis to maintain a good focusing position when the wavelength is scanned by rotating the grating. The profile of impurity emissions is projected through the space-resolved slit, which is set horizontally. The spectrometer is equipped with two gratings with 2400 grooves/mm and 2160 grooves/mm, respectively. The overall aberration of the system is reduced by accurate detector positioning. As a result, the total spectral broadening can be reduced to about 0.013 nm. The simulated performance of the system is found to satisfy the requirement of measurement of impurity emissions from the divertor area of the EAST tokamak.     

强流回旋加速器静电注入偏转板设计方法研究

从离子在回旋加速器静电注入偏转板中的运动方程出发，对注入偏转板完成了了计算机辅助设计，并给出辅助加工数据。计算设计和束流仿真过程全部在ＰＣ－４８６微机上完成，形成一个注入偏转板设计软件包，并且可以与已开发的“智能化回旋加速器主磁铁ＣＡＥ系统”配套使用，使回旋加速器的整机开发前进了一步。     

Development of Decommissioning Engineering Support System (DEXUS of the Fugen Nuclear Power Station

The Fugen Nuclear Power Station (NPS) was shut down permanently in March 2003, and preparatory activities are underway to decommission the Fugen NPS.

An engineering system to support the decommissioning is being developed to create a dismantling plan using state-of-the-art software such as 3-dimensional computer aided design (3D-CAD) and virtual reality (VR). In particular, an exposure dose evaluation system using VR has been developed and tested.

The total system can be used to quantify radioactive waste, to visualize radioactive inventory, to simulate the dismantling plan, to evaluate workload in radiation environments and to optimize the decommissioning plan. The system will also be useful for educating and training workers and for gaining public acceptance.     

Development of COMPAS,Computer Aided Process Flowsheet Design and Analysis System of Nuclear Fuel Reprocessing

A computer aided process flowsheet design and analysis system, COMPAS has been developed in order to carry out the flowsheet calculation on the process flow diagram of nuclear fuel reprocessing. All of equipments, such as dissolver, mixer-settler, and so on, in the process flowsheet diagram are graphically visualized as icon on a bitmap display of UNIX workstation. Drawing of a flowsheet can be carried out easily by the mouse operation. Not only a published numerical simulation code but also a user's original one can be used on the COMPAS. Specifications of the equipment and the concentration of components in the stream displayed as tables can be edited by a computer user. Results of calculation can be also displayed graphically. Two examples show that the COMPAS is applicable to decide operating conditions of Purex process and to analyze extraction behavior in a mixer-settler extractor.     

HIRFL-SSC注入引出位置调整控制系统的研制

介绍了兰州重离子加速器控制系统中分离扇回旋加速器（SSC）注入引出静电偏转板控制系统的硬件结构和软件设计。该控制系统实现了对位置调整电机的计算机控制和Windows界面操作，使SSC注入引出位置调整更加方便和准确。     

Computer Aided System for Generating Fuel Shuffling Configurations Based on Knowledge Engineering

In a PWR core, approximately 1/3 of the burned fuels are replaced by fresh fuels after about a year's operation. Reload cores are designed so as to minimize the radial power peaking factor under design requirements and some administrative constraints. The conventional way of generating an appropriate fuel loading pattern is a method of trial and error, which is laborious and requires much computer time. A computer aided system has therefore been developed to speed up and make more efficient the determination of fuel shuffling configurations in reload cores. The system consists of a rule-base system employing artificial intelligence techniques, a pin-wise diffusion code and a feedback program based on fuel assembly power distributions. It was successfully applied to cores with only burnable poison rods, with gadolinium-dispersed fuels and also to cores employing low leakage fuel management strategy.     

基于蒙特卡罗模拟法的安全壳喷淋覆盖率计算方法研究

为建立安全壳喷淋覆盖率可靠、快速的计算方法，以对安全壳喷淋系统的设计研究提供新的辅助手段，本研究采用理论分析的方法，建立了基于蒙特卡罗模拟法的安全壳喷淋覆盖率计算模型。通过与基于计算机辅助设计（CAD）的安全壳喷淋覆盖率计算结果进行对比，验证基于蒙特卡罗喷淋覆盖率计算方法的适用性。结果表明，两种方法的计算误差在1%以内。因此，本研究建立的基于蒙特卡罗模拟法的安全壳喷淋覆盖率计算方法可靠且具有广泛适用性，对比CAD软件的喷淋覆盖率计算法，新的方法计算速度更快，人因错误率更低，有利于敏感性分析，可大幅提高安全壳喷淋系统设计能力。      

Heavy-ion microbeam system for cell irradiation at Kyoto University

We have developed a heavy-ion microbeam system for cell irradiation that uses an 8-MV tandem Van de Graaff accelerator at Kyoto University. Using a pair of apertures as the final collimator, microbeams of carbon, fluorine, and silicon were extracted to the atmosphere with few background particles. We used a thin transmission scintillator and a photomultiplier detector to accurately measure the number of extracted particles. To examine beam spreading, the beam profile was measured by observing tracks of an irradiated CR-39 track detector. The two disks with holes which were added to the collimating apertures reduced background radiation due to secondary X-rays and electrons from the apertures.     

CCD光谱仪的控制系统及数据处理

本文介绍了CCD光谱仪的控制系统及数据处理方法。为了实现光谱测量的自动化,设计了驱动电路控制和计算机控制系统。编制的光谱软件,在对弱谱信号进行处理,奇偶差异信号修正以及光谱灵敏度的补偿后,大大提高了测量精度。