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在一些设备研发或特定裂变核材料生产环境中,需使用大量中子探测器进行中子通量分布测量以确定生产状态,这一测量过程中,各中子探测器的相对效率尤为重要。为统一此类生产线的测量标准,并保证对目标对象测量的准确性,本文设计了一套长期用于同一生产线开展批量3He探测器相对效率标定的系统。通过对探测装置设计分析,结合后端多道分析器,开展3He探测器探测效率标定系统的理论模拟与实验验证,并对系统中由装置均匀性、多道死时间等产生的误差进行修正,为3He探测器在生产线上大批量使用、更换及维护提供有效依据。 相似文献
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碘化锂晶体闪烁体具有中子测量效率高、探测器尺寸小等优点,它是目前相当成熟和用途广泛的探测器,在中子测量及环境监测等各方面均有广泛应用,它由闪烁体、光导、光电倍增管、高压四部分组成。本工作利用Monte Carlo程序研究了6LiI/natLiI闪烁体探测器尺寸与探测效率的关系,并通过GEANT4及MCNP程序模拟计算了高富集度的6LiI晶体和天然LiI晶体及纯7LiI晶体的探测效率。从理论模拟结果可以看出10 mm厚度的两种探测器对热中子探测效率都很高,6LiI达到98%,而natLiI也能达到65%。利用反应堆热中子刻度了6LiI/natLiI闪烁体探测器的热中子探测效率,考虑了铅砖及高密度聚乙烯的散射,以及环境中子的贡献后,实际测量6LiI探测器探测效率在90%左右,natLiI探测器探测效率在70%左右。 相似文献
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针对国内中子散射谱仪对高效率高位置分辨的热中子探测器需求,对基于多层掠入射涂硼多丝室的新型位置灵敏中子探测器进行了模拟研究。利用蒙特卡洛模拟软件Geant4对探测器的中子探测效率、位置分辨率以及基材对中子的散射进行了模拟仿真。结果表明,采用掠入射多层结构可以实现较高的中子探测效率和位置分辨率。当掠入射角度为5°时,采用3层结构可以对波长2.5 A的热中子实现62%的探测效率;对于2 mm的阳极丝间距,掠入射结构下探测器的位置分辨(FWHM)可达0.286 mm。 相似文献
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针对国内中子测井所使用探测器探测效率不能满足实际应用的情况,采用~(241)Am-Be中子源和LaBr_3:Ce探测器在中石油公司一个放射性同位素中子测试井中对H、C、Fe等几种地壳元素进行了测量,并与现今测井常用的锗酸铋(Bismuth Germanium Oxide,BGO)探测器进行对比测量。测得的能谱结果对比发现,进行地壳元素测量时LaBr_3:Ce探测器比BGO探测器具有更高的能量分辨率,并且在相同外部测试条件下BGO探测器探测到Fe峰非常微弱。因此将LaBr_3:Ce探测器进一步应用到测井中的市场前景广阔。 相似文献
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微小角中子散射谱仪是中国散裂中子源(China spallation neutron source,CSNS)工程目前在建的谱仪之一,为了实现微小角散射模式下中子衍射的精确测量,要求中子探测器的位置分辨≤2 mm、探测效率≥60%@0.4 nm。在此物理精度需求下,研制了基于6LiF/ZnS(Ag)闪烁屏、波移光纤阵列和硅光电倍增管(Silicon Photomultiplier,SiPM)结构的位置灵敏型闪烁体探测器,以实现热中子的高效率和高分辨实时探测。探测效率测试以标准3He管的入射中子数归一化计算得到,位置分辨通过含有“CSNS”字样的含硼铝板验证。本文详细研究了0.5 mm直径波移光纤的光传输性能,对比了不同硅光电倍增管的增益和热噪声特性,并以此设计了有效面积为300 mm×300 mm的探测器工程样机。经测试,该探测器的位置分辨为1.2 mm×1.2 mm,探测效率为(61.8±0.2)%@0.4 nm,达到了工程设计指标,满足了CSNS工程微小角谱仪的中子衍射测量需求。 相似文献
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微结构半导体中子探测器(MSND)除了具有体积小、时间响应快、工作偏压低以及易于与读出电子学系统集成等优点外,还解决了二维平面半导体中子探测器存在的探测效率极低的问题(5%),其在军用和民用领域都具有良好的发展前景。介绍了微结构半导体中子探测器的中子探测原理,简述了其发展概况,综述了近年来的研究进展,展望了微结构半导体中子探测器的研究方向和应用前景。 相似文献
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石宗仁 《核电子学与探测技术》1997,17(5):390-390
本文概述了近年来探测快中子的新技术,它们分别是:抑制γ射线、热中子和带电粒子的符合谱仪;高分辨宽能量范围正比计数器的^3He夹心谱仪;含氢的纤维闪烁体用于抑制γ射线、中子位置分布和中子能谱测量;及含锂的纤维玻璃闪烁体用于长中子计数器测平均中子能量;中子的直接探测;用于中高能和重离子核物理的多元件阵列快中子探测器和极化仪;用于核核查的中子源影像探测器;高入射氘核能量和高能中子的伴随粒子技术等7个方面 相似文献
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BF3中子探测器阵列探测效率的蒙特卡罗计算 总被引:1,自引:0,他引:1
在用241Am-Be中子源对BF3中子探测器阵列探测效率标定的基础上,用蒙特卡罗方法对其探测效率进行了模拟计算,获得了比较满意的结果.然后用蒙特卡罗方法对BF3中子探测器阵列的探测效率进行了研究.研究结果表明,焦面探测器具有较好的探测效率. 相似文献
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描述了一种联合使用活化探测器和成像盘技术(IP)探测中子注量的方法。利用这种方法测量了高能中子束线装置KENS(KEKspallationneutronsourcefacility)中混凝土屏蔽体内中子的空间分布。高能中子注量衰减的实验结果与使用蒙特卡罗程序MARS14模拟计算的结果符合很好。结果表明,联合使用活化探测器和成像盘技术可以同时测量多个位置的中子注量,直观展现出混凝土屏蔽体内中子强度的分布情况。 相似文献
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D. Lattanzi M. Angelone M. Pillon S. Almaviva M. Marinelli E. Milani G. Prestopino A. Tucciarone C. Verona G. Verona-Rinati S. Popovichev R.M. Montereali M.A. Vincenti A. Murari JET-EFDA Culham Science Centre OX DB Abingdon UK JET-EFDA contributors 《Fusion Engineering and Design》2009,84(7-11):1156-1159
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《Journal of Nuclear Science and Technology》2013,50(7):608-617
A new technique for estimating the neutron energy spectrum with CR-39 track detectors has been proposed for application to a singly pulsed neutron field where prevailing counters cannot operate properly. The CR-39 sample exposed to neutrons was intermittently etched, then the major and minor radii of respective etch pits were measured for each etching stage and the growth curve was obtained. The analysis method of growth curves was also designed, with which both the energy and the angle of recoil protons could be evaluated and converted into the energy of neutrons incident normally. The neutron irradiation experiments were carried out with the 46 MeV electron linear accelerator at the Research Reactor Institute, Kyoto University. It was confirmed from comparing with the reference spectrum measured by the neutron time-of-flight method that the present growth-curve method is useful for the estimation of the neutron energy distribution between about 0.3 and 2 MeV. Moreover, we have experimentally examined the unfolding method suggested by Matiullah and Durrani in order to extend the application of CR-39 detector to higher energies. 相似文献
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Due to their low cost,flexibility,and convenience for long distance data transfer,plastic scintillation fibers (PSF) have been increasingly used in building detectors or sensors for detecting various radiations and imaging.In this paper,GEANT4 Monte Carlo simulation tool was used to obtain some radiation effects of PSF under high-energy neutron irradiation.BCF-20,a plastic fiber material,produced by Saint-Gobain,was used in the simulation.The fiber consists of a core scintillating material of polystyrene and an acrylic outer cladding.Incident neutrons produce energy deposition in fiber through neutron induced recoil proton events.The relationships between energy deposition efficiency and fiber length,fiber radius and incident neutron energy are presented.The variation with those parameters and parameter selection are also analyzed. 相似文献
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Tetsuro Matsumoto Akihiko Masuda Hideki Harano Yoshiaki Shikaze Yoshihiko Tanimura Hajime Seito 《Journal of Nuclear Science and Technology》2017,54(5):529-538
In this study, we developed a 45 MeV neutron fluence rate standard of Japan. Quasi-monoenergetic neutrons with a peak energy of 45 MeV in the neutron standard field were produced by the 7Li(p,n)7Be reaction using a 50-MeV proton beam from an azimuthally varying field (AVF) cyclotron of the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA). The neutron energy spectrum was measured using an organic liquid scintillation detector and a 6Li-glass scintillation detector by the time-of-flight method, and using a Bonner sphere spectrometer by the unfolding method. The absolute neutron fluence was determined using a proton recoil telescope (PRT) composed of the liquid scintillation detector and a Si(Li) detector that was newly developed in the present study. The detection efficiency of the PRT was obtained using the MCNPX code. The peak neutron production cross section for the 7Li(p,n)7Be reaction was also derived from the neutron fluence in order to confirm the neutron fluence of the TIARA high-energy neutron field. The peak neutron production cross section obtained in the present study was in good agreement with those of previous studies. The characteristics of the 45-MeV neutron field in TIARA were successfully evaluated in order to calibrate high-energy neutron detectors and high-energy neutron dosimeters. 相似文献
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《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1988,34(4):499-504
Demand for improved dose-equivalent dosemeters for fast neutrons has been growing in recent years. Among the other dosemeters currently under investigations, electrochemically etched CR-39 detector offers promising applications for fast-neutron dosimetry. In this paper we present, first, our theoretical and experimental work to achieve a nearly flat dose-equivalent response over the range 0.1 to 19 MeV for normally incident neutrons. The paper then outlines a method developed by us to circumvent the problem of direction dependence of the dosemeter. Here, we have attached CR-39 detectors along with the optimized radiator stacks to three adjacent sides of a supporting cube made of Perspex and irradiated with neutrons at different cube orientations. By this means, the direction dependence has been reduced to less than 25%. Finally, a design for practical fast-neutron dosemeter is proposed. 相似文献
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《Fusion Engineering and Design》2014,89(9-10):2184-2188
The need of performing high resolution fast neutron spectroscopy in a very harsh environment like that of the Radial Neutron Camera (RNC) of ITER, requires to develop new detectors and methodologies. Diamond detectors have been proved to be excellent candidates but the electronics needs a substantial improvement. Because of the high radiation level and the temperatures expected near the detector positions in the RNC, the electronics must be placed several meters away. A novel Fast Charge Amplifier (FCA) was developed that, connected to a diamond detector using several tens of meters of low capacitance coaxial cable, is able to produce fast output signals suitable to be processed by digital electronics. These fast output signals allow to operate at high count rates avoiding pile-up problems. This novel amplifier connected to a digitizer is here tested in the neutron energy range from 5 to 20.5 MeV using the mono-energetic neutrons produced by the Van de Graaff (VdG) accelerator of the EC-JRC-IRMM and by the PTB cyclotron. From the measurements the experimental response functions of the diamond detector at different neutron energies were obtained. The shape of the response functions have been compared with that predicted with a routine which was implemented for the Monte Carlo code MCNPX with the scope to validate the calculations versus the experimental data. The goal is to develop a tool which allows to calculate the diamond detector response functions also in term of absolute efficiency. This methodology along with the ability to measure at high reaction rates and the insensitivity to radiation damage launches the system described in this paper as a promising method for neutron spectrometry in the RNC of ITER. 相似文献