一种中子测井仪偏心弓测试装置研制

中子测井孔隙度受多方面环境因素的影响,其中井眼对中子测井的影响较为明显,在中子的测井作业中按照要求必须加偏心器。如何让补偿中子测井仪器的探头部分更好地贴合井壁,是测井施工中必须要解决的问题,对准确掌握地层油气信息具有重要的工程实际意义。为了中子测井仪器的测井效果,同时仪器不至于在井下遇卡,偏心弓需要保持合适的偏心力。为了精确测量偏心力,该文研制一种新的偏心弓测量装置,从其设计方案到实际测试做了相关的研究。通过测试,使其既能够准确的测量中子偏心弓的偏心力,又能够消除安全隐患。     

PNN测井仪工作原理与典型故障维修

PNN测井仪是Hotwell公司研发的一种用于测量饱和度、孔隙度及管外流体的测井仪器.本文介绍了井下仪器的组成,分析了其工作原理,并着重对在使用中所遇典型故障和维修及分析方法进行了阐述.     

一种输出稳定的新型直流稳压电源

本文介绍了一种新型直流电源、它主要是根据三端可调正电压集成稳定压器的应用特点而设计的，这种电源具有输出电压稳定性好，输出可微调的优点。它在Ｃ／Ｏ能谱测井中显示出较好的应用效果。     

核电站堆芯中子注量率测量系统试验平台的设计与应用

核电站堆芯中子注量率测量系统,简称RIC系统,是核电站重要的仪表系统.CPR1000堆型核电站RIC系统的自主化研发过程中,需要建立一套试验平台来对自主化的RIC系统和设备进行功能和性能的试验,使其符合技术规范书的要求.本文根据RIC系统的试验要求,运用电子电路技术设计和开发了RIC系统的试验平台.该平台设计完成后,可...     

中子应力谱仪准直器的模拟计算

为了能具体了解准直器系统对中子应力谱仪的性能参数如:样品处中子注量率、谱仪分辨率等主要指标的影响,对安装于中子应力谱仪上的准直器系统进行模拟和计算.通过设定和优化各个准直器参数.分析它们对谱仪性能指标的影响.模拟过程中,我们主要采用了McStas软件来进行建模及优化计算工作,通过对第一、第二准直器等主要部件的发散度参数α1、α2和长度的组合变化来发现它们对谱仪整体的影响,并且计算它们引起的分辨率改变,最终我们得到在α1:α2=30'下样品处水平方向中子注量率可以达到2.3×106n·cm-2·s-1,垂直方向可达3.5×106n·cm-2·s-1,并且当第一、第二准直器发散角α1:α2=10'时谱仪可以得到它的最好分辨率Fw=0.2,它所对应的应变误差值是应力谱仪测量的最小误差.     

生物样品中微量元素的中子活化分析

本文叙述了近十多年来中子活化分析方法的发展以及在测定生物样品中微量元素所使用的中子活化分析方法,涉及到在生命科学研究中的应用,如对地方病,常见病,癌和生物标准参考物质等。     

生物样品中微量元素的中子活化分析

本文叙述了近十多年来中子活化分析方法的发展以及在测定生物样品中微量元素所使用的中子活化分析方法，涉及到在生命科学研究中的应用，如对地方病，常见病，癌和生物标准参考物质等。     

应用于中子照相的热中子敏感微通道板

介绍了中子成像探测技术的应用。由于直接在微通道板(MCP)玻璃中掺加中子灵敏核素可使MCP对热中子敏感,从而可将MCP事件计数成像探测器的优势成功地应用于以中子为探针的成像探测技术,本文开展了热中子敏感微通道板的研究。通过在MCP玻璃中掺摩尔百分比为3%的Gd2O3,并沿用MCP的制作方法,完成了直径为50mm和106mm的大面阵热中子敏感MCP的制作,并进行了基于这种大面阵热中子敏感MCP的中子事件计数成像探测器的中子成像实验。理论和实验结果都验证了掺摩尔百分比为3%的Gd2O3 MCP可取得对热、冷中子30%~50%的探测效率。最后,进一步介绍了目前开展的封装式中子敏感MCP增强管的研制工作。基于掺Gd2O3的MCP增强管并经光学耦合到CCD或CMOS相机的紧凑混合传感器结构是实现高时空分辨能力的中子照相无损检测技术的有效途径。     

多物理谱仪高精四刀光阑机械设计与分析

四刀光阑是多物理谱仪（MPI）光路控制系统的重要组成部分之一，它的定位精度将直接决定中子束斑分布情况从而影响中子散射实验分析结果的准确性。为了满足高辐射、高磁场、高真空并且空间狭小的工作环境，并且具有较高的定位精度与重复定位精度需求的MPI四刀光阑系统。针对这些需求提出一种新的四刀光阑系统，采用压电陶瓷电机为进给驱动系统、中子吸收材料碳化硼为刀片的方案。实验表明，这种方案具有良好的应用效果，四刀光阑的重复定位精度可以控制在1.5μm，偏摆角误差4.5′，相比于现在使用的四刀光阑有了很大的提升。这套四刀光阑设计方案的提出为类似狭小空间中的高精度、大行程装置的研发提供了一种有效的解决思路。     

DC5361插入测试信号发生器

DC5361是一种PAL制电视测试信号发生器,可提供两类电视测量信号:一类全场测试信号,它带有标准复合同步、消隐信号以及开槽和均衡脉冲等,实际上是一种复合视频图象信号,可供电视台发射通道视频传输系统作静态测量使用;另一类为插入测试     

Monitoring the yield of a borehole neutron generator

In mining, it is important to improve the precision of geophysical instruments in mineral prospecting, especially in the exploration of oil and gas fields. The possibility of creating instruments for monitoring the neutron yield of a borehole neutron generator in neutron–neutron logging systems is considered. One possibility is to employ detectors based on natural diamonds, which are a valuable resource. Their use in hightech geophysical instruments for prospecting may be regarded as a valuable step in the efficient utilization of natural resources, which is an important goal at this time. Experience shows that Russian-made diamond detectors of the proposed design are satisfactory replacements for the instruments currently used to monitor the yield of a borehole neutron generator in neutron–neutron logging systems. Tests of the detectors in the AINK-43M pulsed neutron–neutron logging system demonstrate the improved productivity and precision of the measurement system.     

Development of compact D-D neutron generator

In recent years, due to specific features of compact neutron generators, their demand in elemental analysis and detection of the illicit materials has been increased in scientific community. Compact in size, controlled operation and radiation safety like features of neutron generator is suitable for research work with illicit materials. An accelerator based neutron generator can be operated in steady mode as well as in pulse mode. The main embodiment of this type of generator includes ion source, ion acceleration system and target. We are developing such type of neutron generator. This consists of one in-house developed penning ion source, a single electrode acceleration gap and one deuteriated titanium target or virgin titanium target. The neutron generator was operated at 80 kV acceleration potential, a deuterium pressure of 0.1 mTorr and ion source potential at 1 kV. The neutron generation was confirmed by the solid state nuclear track detector CR-39. In this report, we will discuss various physics and technical issues related to the important components of this generator, operation of the generator and neutron detection.     

斩盘产生的中子脉冲特性模拟

为更好地进行转盘式中子斩波器的设计，分别对单盘和异向双盘的中子脉冲的形成特性进行了模拟计算。采用国际上常用的Mcstas模拟计算软件，建立单盘和双斩盘的结构模型，分别针对相应物理参数进行模拟。获得了相关物理参数对斩盘产生脉冲的影响曲线，讨论了单斩盘与双斩盘脉冲形成的束流特性的差别与优缺点。结合实际应用，针对异向旋转双盘，在特定物理参数下，第二斩盘窗口宽度的选择应在不超过34mm的范围内综合选择。计算结果可为斩波器的理论设计以及相关物理参数的选择提供理论支撑。     

A monitoring and measuring module for tagged neutron experiments

A tagged neutron technology for remote neutron monitoring is used to reduce the background counting rate in recording of useful events. The key elements of the technology are a neutron generator with a built-in α-particle detector, nanosecond electronic system, and fast detectors of secondary radiation produced by emitted neutrons. A module for monitoring and measuring the pulse-height and time parameters of the secondary radiation detector with a time reference to the α-particle detector is described. A prototype of the experimental setup comprising the main components of a standard system based on the tagged neutron technology has been designed to test the module. Numerical calculations have been performed to simulate the γ-ray and neutron transport and the event recording procedure as applied to the geometry of the experimental setup. The time errors and the main sources of background events in measurements using the tagged neutron technology have been investigated. Background counts are shown to affect only slightly the useful data acquired in this geometry.     

Electrophysical and structural optimization in monitoring the neutron yield of borehole generators

In mining, it is important to ensure effective monitoring and to improve the precision of the geophysical instruments used in mineral prospecting. The electrophysical and structural optimization of instruments for monitoring the neutron yield of borehole generators in neutron–neutron logging systems is considered. Diamond detectors have been developed and successfully employed for this purpose. The expanded use of diamonds, especially in instruments, improves the utilization of natural resources. In regular equipment for monitoring the neutron yield of borehole generators in neutron–neutron logging systems, the consequences of introducing Russian diamond detectors are studied. Specifically, the influence of the ambient parameters on the borehole instrument (temperature stability of the diamond detector in the range 20–140°C) is determined; and the linearity of the conversion characteristic of the fast-neutron monitor in the system is investigated by measuring the fluctuation of the output-signal amplitude in the range 20–140°C.     

中子斩盘斩束效果的模拟计算

转盘式中子斩波器广泛地应用于飞行时间模式中子散射谱仪上,斩盘斩出的脉冲柬流特性直接影响着谱仪性能。为更好地进行转盘式中子斩波器的设计,采用Mcstas程序软件,分别对单盘和双盘的中子斩波特性进行了模拟计算。获得了相关物理参数对脉冲注量率和发散度的影响关系曲线。通过理论计算可以了解相关物理参数对斩波特性的影响,计算结果可为斩波器的理论设计以及相关物理参数的优化选择提供理论参考。     

中子活化法研究唐巴勒蛇绿岩中超镁铁质岩的地球化学特征

用预浓集中子活化法测定唐巴勒蛇绿岩中超镁铁质岩中稀土元素(REE)含量,用仪器中子活化法测定其中其他微量元素。依据测定结果分析了超镁铁质岩中稀土元素及其他微量元素的地球化学特征:认为,超镁铁质岩为上地幔经历部分熔融后残留的地幔物质。     

中子照相技术及其应用

本文简述中子照相的原理、方法和特征。包括中子源 ,中子转换屏 ,中子成像技术等关键技术。给出在 4 5MV静电加速器上快中子照相的结果。并概述中子照相技术的一些应用实例     

The Feasibility of Neutron Moderation Imaging for Land Mine Detection

Neutron moderation land mine detection involves irradiating the ground with fast neutrons and subsequently detecting the thermalized neutrons which return. This technique has been studied since the 1950s, but only using non-imaging detectors. Without imaging, natural variations in moisture content, surface irregularities, and sensor height variations produce sufficient false alarms to render the method impractical in all but the driest conditions. This paper describes research to design and build a prototype land mine detector based on neutron moderation imaging. After reviewing various neutron detector technologies, a design concept was developed. It consists of a novel thermal neutron imaging system, a unique neutron source to uniformly irradiate the underlying ground, and hardware and software for image generation and enhancement. A proof-of-principle imager has been built, but with a point source offset from the detector to roughly approximate a very weak uniform source at the detector plane. Imagery from the detector of mine surrogates is presented. Realistic Monte Carlo simulations were performed using the same two dimensional neutron imaging geometry as the detector in order to assess its performance. The target-to-background contrast was calculated for various soil types and moisture contents, explosive types and sizes, burial depths, detector standoffs, and ground height variations. The simulations showed that the neutron moderation imager is feasible as a land mine detector in a slow scanning or confirmation role and that image quality should be sufficient to significantly improve detector performance and reduce false alarm rates compared to non-imaging albedo detection, particularly in moist soils, where surface irregularities exist and when the sensor height is uncertain. Performance capability, including spatial resolution and detection times, was estimated.     

Construction of consistent neural network empirical physical formulas for detector counts in neutron exit channel selection

Proper selection of neutron exit channels following heavy-ion reactions is important in nuclear structure physics. A knowledge of detector counts versus number of neutron interaction points per event can be useful in this selection. In this paper, we constructed layered feedforward neural networks (LFNNs) consistent empirical physical formulas (EPFs) to estimate the detector counts versus number of neutron interaction points per event. The LFNN-EPFs are of explicit mathematical functional form. Therefore, by various suitable operations of mathematical analysis, these LFNN-EPFs can be used to derivate further physical functions which might be potentially relevant to neutron exit channel selection.