行人放射性快速识别仪的研制

为保护重要场所区域安全,提升防止携带特殊核材料或脏弹等引起的核恐怖威胁的能力,研制了行人放射性快速识别仪。该识别仪由Na I探测器和单片嵌入式现场可编程门阵列(Field Programmable Gate Array,FPGA)组成,采用数字梯形滤波成形技术和幅度谱数据处理优化实现方法,能够在1 s内实现γ辐射探测、同位素识别及自动分类。在662 keV处能量分辨率为7.44%,在距离探测器中心点1 m处,置信度99%条件下,最低可探测活度41.9 kBq,对5类~(137)Cs放射源能实现可靠报警,性能达到国外同类产品水平。     

快中子脉冲堆用快速响应保护仪

为了保证快中子脉冲堆在爆发脉冲后迅速停堆,研制了快速响应保护仪。该仪器采用ST401快速响应塑料闪烁体配以GDB-44F型光电倍增管作为探测器,通过电流放大后输入触发器单元,在功率超过保护设定值后12μs内输出触发信号,触发主安全块在100ms内下降5mm,使堆处于深次临界状态。在CFBR-II堆的200余次脉冲运行中,快速响应保护仪触发主安全块下降5mm的时间小于90ms,保障了堆的安全。     

快中子脉冲堆用快速响应保护仪

为了保证快中子脉冲堆在爆发脉冲后迅速停堆,研制了快速响应保护仪.该仪器采用ST401快速响应塑料闪烁体配以GDB-44F型光电倍增管作为探测器,通过电流放大后输入触发器单元,在功率超过保护设定值后12μs内输出触发信号,触发主安全块在100ms内下降5mm,使堆处于深次临界状态.在CFBR-Ⅱ堆的200余次脉冲运行中,快速响应保护仪触发主安全块下降5mm的时间小于90ms,保障了堆的安全.     

基于Walsh-Hadamard变换与栈式自编码快速核素识别

为解决短时辐射环境核素组成分析问题,提出了基于Walsh-Hadamard变换与栈式自编码快速核素识别算法。该算法采用探测率和精确核素识别能谱计数两个参数作为评价新型核素识别算法性能的指标。实验结果表明:新核素识别算法在满足精确核素识别能谱计数的条件下,性能不受探测时间、核素个数和探测距离的影响,而且对运动放射源具有较好的识别性能。新核素识别算法可用于辐射检测设备的快速核素识别。     

便携式放射性核素识别仪原理性样机的研制

介绍了中国工程物理研究院核物理与化学研究所研制的基于多道谱仪的多功能便携式核素识别仪原理性样机,可用于放射性核素的检测、剂量率监测、放射源定位以及核能谱采集与核素识别。当发现环境及流出物中放射性异常后,利用便携式放射性核素识别仪对可疑部位进行放射性核素快速定位、快速识别和强度测量,并可预先给出足够精确的γ剂量率的测量结果,保证在定位和识别时操作人员的辐射安全。     

利用CUDA技术实现锥束CT图像快速重建

锥束CT三维重建算法的计算量和传输量巨大,仅利用CPU来计算,无法满足实时、快速、准确重建的要求,根据图形处理器运算能力强、存储带宽大的特点,研究了一种不需要学习图形API,就可以在图形处理器上实现三维重建算法的快速运算的方法。该方法采用基于统一计算设备架构的图形处理器,通过这种新架构的编程模式,利用图形处理器中的流处理器来加快滤波和反投影计算,实现了FDK算法的重建加速,与利用图形API的重建方法相比,开发门槛较低。对于尺寸为5123的单精度浮点数据格式的图像,重建时间可以缩短到一分钟以内,并且GPU与计算机的传输时间小于1秒。实验结果表明与仅利用CPU的重建方法相比,本文提出的图像加速方法得到了较高的时间加速比。     

数字化核测系统通信数据传输算法应用

数字化通信具有稳定性好、可靠性高的优点,越来越广泛应用于仪控系统,特别是新一代核电厂仪控系统。现在我国核电建设事业快速发展,引进了三代AP1000技术,但是大部分核测系统还是由国外厂商供货,尤其是数字化核测系统更是空白。在与现场核测仪表配套定制的数字化仪控系统设计中,需要考虑作为信号采集、处理、阈值比较和控制的各个环节,其中如何快速、智能地处理通信数据也是大家经常关注和研究的重点。数字化通信数据传输算法针对数字化核测系统的快速可靠的循环数据交互任务而设计,目的是解决系统采用的RS485高速数据总线由于自身的物理介质特点而造成的实时控制时间和设备带点量限制的问题。数字化核测系统多点数据信息量交换时,可通过该算法保证在限定系统扫描周期时间内,完成总线每次正常传输足够数据设备信息。     

基于概率神经网络的放射性核素快速识别方法研究

针对传统神经网络在核素识别中训练效果弱,易陷入局部极小、收敛速度慢等问题,提出了基于概率神经网络的核素识别方法,采用样本的先验概率和最优判定原则对新的样本进行分类。该方法利用能谱预处理过程获得的谱峰宽度、特征能量射线强度、峰面积等特征信息建立训练与测试样本,采用训练样本对概率神经网络模型进行训练,并进行了分类识别仿真实验。通过CZD探测器对3种核素不同组合的实测能谱进行测试,并与传统的神经网络算法进行对比表明:此方法具有较高的识别效率及准确率,可应用于安全监控、失控放射物探测等快速核素识别领域。     

爆炸物探测技术研究进展

爆炸物探测技术研究课题于2002年通过中期评估后,2003年,在爆炸物探测的实验室科研样机的研制方面取得了阶段性成果。实验室样机可探测到乌洛托品、亚硝酸钠和RDX炸药的NQR信号,样机的有效探测体积达到34 L,静态环境下可可靠探测200 g黑索金炸药,测量时间为10 s。 本年度完成的主要工作如下。 1)功率放大器的研究和改进 在自制和国产的功率放大器上进行了部分样品的检测试验;完成了引进4 000 W脉冲射频功率放大器的验收、调试和使用研究。 2)探测器的研制、改进和实验研究 先后研制了平面型、螺线管型多种不同体积、不同结构的探头,目前…     

宇宙射线μ子探测高Z材料的仿真研究

利用Geant4建立宇宙射线μ子探测高Z材料的仿真系统,采用最大似然算法,研究用于μ子探测的位置灵敏探测器漂移管的位置分辨率及系统成像时间对成像结果的影响。当漂移管的位置分辨率优于200μm、成像时间在1～2min内可对相对独立的高Z物质快速识别,本研究也为漂移管的设计加工提供了理论依据。     

Development of Data Processing Software for NBI Spectroscopic Analysis System

A set of data processing software is presented in this paper for processing NBI spectroscopic data.For better and more scientific managment and querying these data,they are managed uniformly by the NBI data server.The data processing software offers the functions of uploading beam spectral original and analytic data to the data server manually and automatically,querying and downloading all the NBI data,as well as dealing with local LZO data.The set software is composed of a server program and a client program.The server software is programmed in C/C++under a CentOS development environment.The client software is developed under a VC6.0 platform,which offers convenient operational human interfaces.The network communications between the server and the client are based on TCP.With the help of this set software,the NBI spectroscopic analysis system realizes the unattended automatic operation,and the clear interface also makes it much more convenient to offer beam intensity distribution data and beam power data to operators for operation decision-making.     

An efficient execution of Monte Carlo simulation based on delta-tracking method using GPUs

An efficient execution method for Monte Carlo simulation using graphic processing unit (GPU) is proposed. The delta-tracking method is used since the delta-tracking method can reduce conditional branches and complexity of code implementation, which degrade computational performance on GPUs. In order to improve parallel efficiency in the eigenvalue calculation, generated fission neutrons are recorded using the atomic operation which avoids the data race in GPUs. We also propose a method to efficiently tally neutron flux in a region. The present method is based on the atomic operation and use of fixed-point type number instead of common floating-point type number. The verification calculations using the C5G7 benchmark problem show effectiveness of the proposed numerical algorithms on GPUs through comparison with calculations using central processing units.     

一种基于 DSP 的高速数据获取及处理系统

本文介绍了一种基于ＤＳＰ的高速数据获取及处理系统的设计和实现。它能够以１６．６ＭＨｚ的速度完成大容量数据获取（可记录长达５１２ｋ字的采样）。而且能够实现各种灵活多样的数据处理算法，尤其是能够实时完成其中许多处理方法。     

DAQ software architecture for Aleph, a large HEP experiment

The Aleph experiment has over 700000 electronics channels and is expected to generate over 500 Mbytes of data per second. The data acquisition system (DAQ) has been designed to process information from different parts of the detector in parallel using a large number of processing elements. The authors describe the architecture of the software used to implement the readout functions and to configure the system for data acquisition. The software environment, data-flow architecture, control-flow architecture, FASTBUS management, Aleph resource manager, and Aleph partition manager are discussed     

Time-Resolved Emission Spectroscopic Study of Laser-Induced Steel Plasmas

Laser-induced steel plasma is generated by focusing a Q-switched Nd:YAG visible laser(532 nm wavelength) with an irradiance of 1 x 109 W/cm2 on a steel sample in air at atmospheric pressure.An Echelle spectrograph coupled with a gateable intensified charge-coupled detector is used to record the plasma emissions.Using time-resolved spectroscopic measurements of the plasma emissions,the temperature and electron number density of the steel plasma are determined for many times of the detector delay.The validity of the assumption by the spectroscopic methods that the laser-induced plasma(LIP) is optically thin and is also in local thermodynamic equilibrium(LTE) has been evaluated for many delay times.From the temporal evolution of the intensity ratio of two Fe I lines and matching it with its theoretical value,the delay times where the plasma is optically thin and is also in LTE are found to be 800 ns,900 ns and 1000 ns.     

Spectroscopic factors for single-nucleon transfer in the A = 21–44 region

The present paper is a review of measured spectroscopic factors for single-nucleon stripping and pick-up reactions leading to bound states in final nuclei in the A = 21–44 region. All values were recalculated with the same set of normalization constants. This set leads to internal consistency of the data, that is, the spectroscopic factors for (d,n) and (³He,d) are equal within the errors, as are those for (p,d), (d,t), and (³He,α). The same holds for pairs of reactions, exciting mirror states, such as (d,p) and (³He,d), or (p,d) and (d,³He), and for pairs of inverse reactions connecting ground states of stable nuclei, such as (d,p) and (p,d). The deviations from the averages lead to the assignment of a 25% experimental error to individual measurements. Averaging of the data produces a “best set” of spectroscopic factors (with errors given), which can be used for comparison with theoretical calculations. The best values obtained generally do not exceed sum-rule limits.     

光谱学方法在锕系/镧系元素配位化学研究中的应用

锕系/镧系金属离子的配位化学对于控制其在后处理流程中的走向、开发新型萃取剂及反萃剂、预测长寿命锕系金属离子在环境中的迁移行为、降低其在生物体中的毒性均有重要意义。光谱学方法是配位化学研究的重要手段,不仅可用来测定配位反应热力学数据,还能提供配位模式、配合物键长、键角等信息。本文在概述光谱学方法用于锕系/镧系元素配位化学研究最新进展的基础上,重点介绍荧光光谱和拉曼光谱在配合物热力学数据测定及结构分析方面的应用,并展望多光谱联合研究方法在锕系/镧系元素配位化学研究中的应用前景。     

椭偏光度法研究溶胶-凝胶SiO2薄膜的光学性能

用溶胶-凝胶工艺在碱性、酸性催化条件下制备具有纳米多孔结构的SiO2薄膜。用反射式椭圆偏振光谱仪测试薄膜的椭偏参数,并用Cauchy模型对椭偏参数进行数据拟合,获得了溶胶-凝胶SiO2薄膜光学常数在300~700 nm波段的色散关系。用场发射扫描电子显微镜FE-SEM研究了薄膜表面微结构,并讨论表面微结构与光学性能间的关系。结果表明:制备条件所引起的薄膜微结构差异对光学常数的色散关系变化趋势无影响;薄膜光学常数的大小则与微结构有关,折射率大小与薄膜孔洞率成反比。     

Development of a real-time magnetic island reconstruction system based on PCIe platform for HL-2A tokamak

A real-time magnetic island reconstruction(MIR) system based on PCI express platform for HL-2 A tokamak is introduced. The front-end analog circuit and high performance analog-to-digital converters complete high-precision synchronous sampling of 18 channel Mirnov signals, and the application of PCIe platform and direct memory access technology enables high speed data transmission between graphics processing unit and field programmable gate array(FPGA).FPGA, as a mainstream high speed parallelizable computing tool, was used to implement the MIR algorithm, while a parameter table is established in an external double data rate SDRAM to improve the computational efficiency. The software of the MIR system is developed with Compute Unified Device Architecture 8.0 in Centos 6 system, which mainly realizes driver development, data transmission, network communication, parameter calculation and system control. This system has been tested in HL-2 A plasma discharge experiment, and the reconstructed magnetic island structure can achieve a spatial resolution of 1.02 cm while the time resolution can reach 2 ms.     

A modernized and versatile startup reactivity measuring system installed at NPP Paks and its application for subcritical systems

In 2004 the Hungarian Paks NPP completed a project for upgrading the reactivity measuring system applied during reactor startup experiments. Almost all components of the previous system were replaced, only ex-core ionisation chambers remained unaltered. New hardware and software components were introduced for neutron flux signal handling, for data acquisition, as well as for measurement evaluation and data presentation. High-precision picoamper meters were installed at each reactor unit, current signals are handled by a portable signal processing unit. The system applies an accurate on-line reactivity calculation algorithm based on the point-kinetic model with six delayed neutron groups. Detailed off-line evaluation and analysis of startup measurements can be performed on the portable unit, as well.The paper describes the architecture, data acquisition modules, services and man–machine interface of the new system. Functions and results are illustrated with measured data recorded during a startup of Unit 3. In 2003 and 2004 the RMR was installed and tested at all Paks NPP units successfully and now it is in regular use during unit startups.The second part of the paper illustrates an extension of the new system to perform reactivity measurements using the well-known Rossi-α and Feynman-α statistical methods. The modified system was needed to estimate the reactivity of a subcritical system formed by damaged fuel assemblies stored at the fuel service pit of Paks Unit 2. Theoretical background of the applied algorithms is outlined, then results of validation tests and on site measurements are treated. The measurements have shown that the subcriticality of the damaged fuel was sufficiently deep if the high boron concentration in the fuel service pit was maintained.