基于碲锌镉探测器的能谱放大器

本文简要介绍了能谱放大器的工作原理,特别是新研制的放大器根据CdZnTe探测器的特点在原有能谱仪的基础上进行的改进和完善,及仪器性能、实际测量结果等.它具有高计数率时比原有放大器分辨率和稳定性都好.本放大器还适用于Si(Li)探测器、正比计数管和闪烁探测器.     

地学应用中的便携式微机多道能谱仪

便携式机多道能谱仪以笔记本式计算机的为核心,采用１２位逐次逼近型Ａ／Ｄ转换芯片,研制成软硬件相结合的２０４８道能谱仪,讨论了适用于地学的野外微机多道能谱仪的硬件电路和软件特点,以及在γ能谱测量和Ｘ荧光测量全谱分析中的初步应用情况,该仪器及其研制技术也适用于其他有关核潜测量研究。     

一种前端ASIC芯片测试系统的设计与实现

介绍了一种专用集成电路芯片性能测试系统的设计与实现,该芯片适用于构建硅探测器前端读出电子学.描述了测试系统主要硬件电路设计,基于CPLD的快读出控制时序发生模块的实现,利用并口线来模拟I2C总线的方法,系统的调试和主要性能的分析.     

16通道GEM探测器前端读出ASIC的设计

介绍了用于GEM(Gas Electron Multiplier)探测器读出的ASIC芯片GEMROC(GEM ReadoutChip)的设计.该芯片采用Chartered 0.35μm 2P4M CMOS工艺,单片集成16个读出通道,每个通道包括电荷灵敏前放(CSA)、CR-(RC)2成形电路和驱动电路.增益和成形时...     

基于PDA和蓝牙的便携式多道γ能谱仪

介绍一种基于PDA和蓝牙并嵌入GPS的便携式多道7能谱仪,该仪器采用数字化探头和PDA分体式设计,以PDA为核心,开发了基于Windows CE平台的γ能谱仪应用软件,实现了γ能谱仪的无线通讯、数据处理及GPS功能.实验结果证明基于PDA和蓝牙的γ能谱仪具有功耗低、抗干扰性强、便携性好等优点,适用于野外现场和室内对各种物质的γ能谱测量.     

乘法器与乘法型DAC在核仪器程控增益放大器中的设计

设计了三种适用于数字能谱仪前端电路的程控增益放大器。AD734组成的高速程控增益放大器不仅可实现±60 db增益范围的调节,0.002 db增益步进,还可以消除核脉冲信号的直流漂移。TLC7528级联DAC与AD5453超小体积DAC构成的程控增益放大器可实现低成本,小体积的应用,且分辨率大于等于14位,可应用于核仪器的谱线漂移精密大范围调节。     

用宇宙线重核测试CR-39径迹探测器性能

本文介绍用宇宙线重核测定CR-39径迹探测器性能的方法。根据穿透探测器重核粒子径迹的蚀刻速率比V=Vr/V_g,测试了国产CR-39的探测灵敏度、一致性和均匀性。     

脉冲峰值保持器的设计方法与元件选择

从峰值保持器的原理出发,从理论上导出了放大器的转换速度、输出电流及保持电容与输入脉冲的上升时间、动态范围的数学式,分析了峰值保持器的主要性能,介绍了放大器和保持电容的选择方法,用OPA615芯片设计了一种高速脉冲峰值保持器.     

便携式能谱仪高性能USB接口模数转换器

介绍了一种便携式能谱仪高性能USB接口模数转换器的设计方案。该谱仪的模数转换器采用带采样保持器的14位高速ADC芯片和带USB接口的16位单片机，简化了电路，提高了性能；利用并道技术和软件滑尺均道技术，减少了模数转换微分非线性，具有体积小、精度高、速度快、非线性小等优点，较好地满足了便携式能谱仪的需要。     

基于FPGA芯片的伽马能谱数据采集系统的研制

叙述了一种基于单片FPGA芯片的伽马能谱数据采集系统.该系统与传统伽马能谱仪相比,一个显著的特点是,可以实现参考源的自动稳谱.着重介绍了APA600芯片的特点和该数据采集系统的工作原理.单芯片的设计可进一步简化电路,提高系统的可靠性.     

微机化便携式γ全谱仪应用软件的几个关键问题讨论

采用笔记本微机作为控制主机的ＣＤ－１０型野外便携式γ全谱仪，克服了单纯以单片机为控制核心的野外γ射线能谱仪之不跳。其基于Ｗｉｎｄｏｗｓ９８系统的应用软件，具有强大的文件管理、图形显示等功能，实现了室内数据处理的野外现场化。并就γ全谱应用软件中的几个关键问题进行了讨论。     

Use of sampling based correction for non-radioactivity X-ray energy calibration

As the requirement of non-radioactivity measurement has increased in recent years, various energy calibration methods applied in portable X-ray fluorescence (XRF) spectrometers have been developed. In this paper, a sampling based correction energy calibration has been discussed. In this method both history information and current state of the instrument are considered and relative high precision and reliability can be obtained.     

高温气冷堆停堆保护系统的多样性分析

为评价高温气冷堆(HTR)停堆保护系统的多样性特征，基于NUREG/CR-6303的分析方法，通过导则中D3评估方法来确定必需的多样性，并采用NUREG/CR-7007的多样性量化评估方法，分析并识别出停堆保护系统7大多样性属性的25条因素值，计算出标准化的多样性量化值。针对系统多样性存在的薄弱点及工程的实际情况，提出了可行的改进方案。重新核算结果表明，改进方案能有效提升系统的多样性量化值。     

Nuclear track detection using thermoset polycarbonates derived from pentaerythritol

The paper describes the synthesis and performance of two polymers as nuclear track detectors, both having alpha sensitivity higher than that of the widely-used polymer CR-39. A homopolymer (PPETAC) from pentaerythritol tetrakis(allyl carbonate) (PETAC) monomer and its various copolymers with allyl diglycol carbonate (ADC) prepared by cast polymerization were successfully used as nuclear track detectors. The copolymer PETAC:ADC 4:6 weight percent shows maximum alpha sensitivity, almost double that of CR-39 under identical experimental conditions. This copolymer can reveal alpha particle tracks from ²³⁹Pu source in about 60 min and ²⁵²Cf fission fragment tracks by chemical etching in less than 30 min, compared to about 120 min and 45 min respectively, required by CR-39. The polymers can be conveniently etched using aqueous sodium hydroxide.     

Closure of the direct containment heating issue for Zion

This paper, which was originally published in more detail (M.M. Pilch, M.D. Allen, D.L. Knudsen, D.W. Stamps and E.L. Tadios, Rep. NUREG/CR-6075, Supplement 1, 1994b (Sandia National Laboratories, Albuquerque, NM)), provides closure of the direct containment heating (DCH) issue for the Zion plant. It incorporates the comments and suggestions of the peer reviewers of NUREG/CR-6075 (M.M. Pilch, H. Yan, and T.G. Theofanous, Rep. NUREG/CR-6075, SAND93-1535, 1994a (Sandia National Laboratories, Albuquerque, NM)) and specifically includes assessments of four new splinter scenarios defined in working group meetings and modeling enhancements recommended by the working groups. In the four new scenarios, consistency of the initial conditions has been implemented by using insights from systems-level codes. was used to analyze three short-term station blackout cases with different leak rates. In all three cases, the hot leg or surge line failed well before the lower head and thus the primary system depressurized to a point where DCH was no longer considered a threat. However, these calculations were continued to lower head failure in order to gain insights that were useful in establishing the initial and boundary conditions. The most useful insights are that the reactor coolant system pressure is low at vessel breach, metallic blockages in the core region do not melt and relocate into the lower plenum, and melting of upper plenum steel is correlated with hot leg failure. The output was used as input to to assess the containment conditions at vessel breach. The containment-side conditions predicted by are similar to those originally specified in NUREG/CR-6075.The methodology originally developed in NUREG/CR-6075 (M.M. Pilch, H. Yan, and T.G. Theofanous, Rep. NUREG/CR-6075, SAND93-1535, 1994a (Sandia National Laboratories, Albuquerque, NM)) was used to analyze the new splinter scenarios. Some modeling enhancements in response to working group discussions were implemented for these analyses. The entrainment of hydrogen pre-existing in the atmosphere into a burning jet was examined more carefully. In addition, the impact of DCH-induced deflagrations on DCH loads was quantified. A new computational tool—the two-cell equilibrium—Latin hypercube sampling (TCE-LHS) code—was developed for this effort to perform Monte Carlo sampling of the scenario distributions. The TCE-LHS code was benchmarked against the original Scenario I calculations in NUREG/CR-6075 performed using the code, which is based on the method of discrete probability distributions. The results were in excellent agreement.The analyses of the new scenarios showed no intersection of the load distributions and the containment fragility curves, and thus the containment failure probability was negligible for each scenario. These supplemental analyses complete closure of the DCH issue for Zion.     

CR-39应用于中子探测的化学蚀刻条件优化研究

CR-39化学蚀刻的主要影响因素有蚀刻温度、蚀刻液种类和浓度以及蚀刻时间等。本研究选用英国Track Analysis Systems公司的CR-39,采用正交法对蚀刻温度、蚀刻液浓度、蚀刻时间进行试验研究,并与公司推荐化学蚀刻条件下的径迹图像、径迹密度进行对比,得出的优化蚀刻条件是:蚀刻温度为85°C、Na OH蚀刻液浓度为7 mol·L ~1,蚀刻时间为90 min。实验同时发现蚀刻温度是这三个因素中对化学蚀刻后净径迹密度影响最大的因素,而蚀刻时间的影响最小。该研究为CR-39应用于中子探测提供了更好的蚀刻条件,节省了实验时间。     

一种实用多道脉冲幅度分析器

便携式核能谱测量仪器一般有低功耗、小体积及低成本等特点,本文以高性能单片微控制器C8051F340为核心,详细介绍了一款多道脉冲幅度分析器的设计方案及相应性能测试,并重点介绍了峰值检测电路的设计及性能测试结果。结合C8051F340高性能特点,在此多道脉冲幅度分析器的基础上增加相应的外围电路及信号调理电路即可构成便携式低功耗核能谱测量系统。     

核径迹-银纳米颗粒改性的CR-39材料制备及其抗红外反射性能

本工作用中国原子能科学研究院HI-13串列加速器提供的³²S离子辐照CR-39样品,产生潜径迹,用紫外灯敏化后在氢氧化钠溶液中蚀刻,使潜径迹成为具有一定孔径的孔（洞）。用真空充氩气的方法在核径迹孔样品表面镀银纳米颗粒。电子扫描电镜图片显示,氩气压强在50～100Pa之间时,银纳米颗粒直径约为60～100nm,纳米颗粒形成球状团簇的大小为3μm。在红外光区（2.5～25μm）测量镀膜样品的反射率,测量结果表明,CR-39表面的核径迹与银纳米颗粒能将红外光区（8.0～25μm）的反射率降低到0.9%,与未经改性的CR-39比较,减低了82%。在5.8和7.8μm处,CR-39的本底反射率分别从9.0%和130%降低到了5.0%和6.8%。