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McStas and Scatter Logger driven calculations of prompt gamma shielding for neutron guides McStas和Scatter Logger驱动中子导管的即时伽马屏蔽计算
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-29 DOI: 10.3233/jnr-190123
R. Kolevatov
McStas ScatterLogger component bundle was adapted for evaluating a contribution to dose rate around neutron guides arising from prompt gamma radiation accompanying neutron capture in the supermirror guide coating upon specular reflection. Thickness of typical shielding materials needed to reduce this contribution to the desired level can be now evaluated directly from running a ray-tracing simulation of the instrument in McStas. An overview of the corresponding modifications to the existing McStas components and description of the newly written supplementary ones is given together with examples and use instructions.
McStas ScatterLogger组件束适用于评估在镜面反射下超镜导膜中伴随中子捕获的快速伽马辐射对中子导膜周围剂量率的贡献。现在可以通过在McStas中运行仪器的光线追踪模拟来直接评估将这种贡献降低到所需水平所需的典型屏蔽材料的厚度。概述了对现有McStas组件的相应修改,并对新编写的补充组件进行了描述,同时给出了示例和使用说明。
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引用次数: 2
Towards innovative, successful and cost-efficient use of beam time 朝着创新、成功和经济有效地利用波束时间的方向发展
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-29 DOI: 10.3233/jnr-200147
E. Lelièvre-Berna, P. Willendrup
This double issue presents some of the work accomplished by two Joint Research Activities (JRAs) of the project World class Science and Innovation with Neutrons in Europe 2020 (SINE2020) financed by the European Commission under the 8th Framework Programme. Within these two JRAs entitled E-tools for Instrumentation and Sample Environment, efforts have been made to explore the full potential of the large scale facilities and enable challenging experiments required by the neutron and muon user communities. In the following pages, we present new McStas components based on Monte-Carlo algorithms to optimise the signal to background ratio, a decisive factor for the success of many experiments. The first McStas bundle allows evaluating one of the major contributions to dose rate around neutron guides. Combined with the next article presenting the investigation of the neutron activation properties of the PE-B4C-concrete recently developed for the European Spallation Source (ESS), this will help facilities to optimise the siting of guides and instruments. The second presented McStas bundle calculates neutron pathways through materials surrounding samples which are generally the most difficult to screen. For the first time, textured materials are considered, taking elastic and inelastic scattering into account, including multiple scattering. The article is followed by a review of different materials for building novel pressure cells for inelastic scattering whose measurements have allowed to determine the effective phonon generalised density of states of these materials, a prerequisite for performing simulations. The next two articles focus on pressure devices. The first one presents the developments of gasket-anvil assemblies for the Paris–Edinburgh cell with 30% improved pressure performance giving a similar signal-to-background ratio. It also describes an improved Bridgman seal package which makes the low-temperature operation of the PE press significantly more reliable. The second article describes a new cell for the investigation of hydrogen storage materials at pressures up to 700 bar and temperatures up to 500°C. The following articles present a simple but very efficient technique for reducing the cool-down times of blue series furnaces by a factor 4 to 5, a comprehensive suite of sample environment equipment for efficient running of muon chemistry experiments over a wide range of conditions, and a portable single-sided NMR setup adapted to a small angle neutron scattering instrument for retrieving both structural and dynamical informations from a single experiment. This issue ends with an article demonstrating that rectangular beam cross-sections with a height over width ratio which mimic the ESS “pancake” moderator beams will lead to an improved homogeneity of the magnetic field integrals of spin echo instruments and an introduction to SECoP, the international Sample Environment Communication Protocol developed on close collaboration with the Int
本期双刊介绍了欧盟委员会根据第八个框架计划资助的2020年欧洲中子世界级科学与创新项目(SINE2020)的两个联合研究活动(JRA)完成的一些工作。在这两个题为“仪器和样品环境电子工具”的联合研究报告中,已经努力探索大型设施的全部潜力,并实现中子和μ介子用户群体所需的具有挑战性的实验。在接下来的几页中,我们介绍了基于蒙特卡罗算法的新的McStas组件,以优化信号与背景比,这是许多实验成功的决定性因素。第一个McStas束允许评估中子引导周围剂量率的主要贡献之一。结合下一篇文章,介绍了最近为欧洲散裂源(ESS)开发的含PE-B4C混凝土的中子活化特性的研究,这将有助于设施优化导向器和仪器的选址。第二个给出的McStas束计算通过样本周围材料的中子路径,这些材料通常是最难筛选的。首次考虑了纹理材料,考虑了弹性和非弹性散射,包括多次散射。在这篇文章之后,我们回顾了用于构建新型非弹性散射压力电池的不同材料,这些材料的测量可以确定这些材料的有效声子广义态密度,这是进行模拟的先决条件。接下来的两篇文章主要讨论压力装置。第一篇介绍了巴黎-爱丁堡电池的垫圈-砧座组件的发展,其压力性能提高了30%,给出了类似的信号背景比。它还描述了一种改进的Bridgman密封封装,它使PE压机的低温操作更加可靠。第二篇文章描述了一种新的电池,用于研究压力高达700巴、温度高达500°C的储氢材料。以下文章介绍了一种将蓝色系列炉的冷却时间减少4到5倍的简单但非常有效的技术、一套用于在宽条件下有效运行μ介子化学实验的综合样品环境设备,以及适用于小角度中子散射仪器的便携式单侧NMR装置,用于从单个实验中检索结构和动力学信息。该问题以一篇文章结束,该文章证明了具有模仿ESS“煎饼”慢化剂光束的高宽比的矩形光束横截面将提高自旋回波仪器的磁场积分的均匀性,并介绍了SECoP,与国际样品环境学会密切合作制定的国际样品环境通信协议。享受阅读吧!
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引用次数: 0
High-pressure cell for in situ neutron studies of hydrogen storage materials 用于储氢材料原位中子研究的高压电池
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-29 DOI: 10.3233/jnr-190116
Neslihan Aslan, C. Horstmann, O. Metz, O. Kotlyar, M. Dornheim, C. Pistidda, S. Busch, W. Lohstroh, M. Müller, K. Pranzas
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引用次数: 0
Conceptual implementation stages for Moroccan PGAA/NI instruments: STAGE I & II 摩洛哥PGAA/NI仪器的概念实施阶段:第一阶段和第二阶段
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-01 DOI: 10.3233/JNR-200171
H. Amsil, A. Jalil, K. Embarch, H. Bounouira, Abdessamad DIDI, K. Laraki, H. Marah, A. Chetaine
The first installation around the tangential beam tube of the Moroccan TRIGA Mark II research reactor comprises combined instruments for Prompt Gamma Neutron Activation Analysis (PGAA) and Neutron Imaging (NI). The implementation of this project is divided over three main stages, namely the installation of the collimator and the primary beam shutter, which is a common section for introduction inside the reactor; the PGAA instruments’ installation; and finally, the installation of the PGNAA/NI combined instruments. The entire design was planned for this project, and detailed information about the first and the second stage is described in this work.
摩洛哥TRIGA Mark II研究堆的切向束流管周围的第一个装置包括快速伽马中子活化分析(PGAA)和中子成像(NI)的组合仪器。本工程的实施分为三个主要阶段,即准直器和主光束百叶窗的安装,主光束百叶窗是反应器内部引入的共同部分;PGAA仪器的安装;最后是PGNAA/NI组合仪器的安装。本设计对整个项目进行了规划,并详细介绍了第一阶段和第二阶段的设计情况。
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引用次数: 2
Neutronics analyses for the conceptual design of the SNS Second Target Station SNS第二目标站概念设计的中子分析
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-01 DOI: 10.3233/jnr-200165
I. Remec, F. Gallmeier
The Spallation Neutron Source, in operation at the Oak Ridge National Laboratory since 2006, was designed to allow the addition of a second target station and an upgrade of the accelerator proton power. Both upgrades are now underway. This paper describes the evolution of the design of the target of the second target station with the emphasis on the effects of the proton beam footprint on the energy deposition in the target, stresses induced by the pulsed operation, and the importance of the residual heat. The moderator configurations and their optimization are discussed. With the utilization of pure parahydrogen moderators, small neutron beam cross-sections, and the specific optimization, neutron beams of the second target station will achieve exceptionally high peak brightness and time-averaged brightness.
自2006年以来,在橡树岭国家实验室运行的散裂中子源被设计为允许增加第二个目标站和升级加速器质子功率。两项升级目前都在进行中。本文介绍了第二靶站靶设计的演变,重点介绍了质子束足迹对靶内能量沉积的影响、脉冲操作引起的应力以及余热的重要性。讨论了慢化剂的配置及其优化。利用纯准氢慢化剂、较小的中子束截面和针对性的优化,第二目标站的中子束将获得异常高的峰值亮度和时间平均亮度。
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引用次数: 3
Measurement of residual strain in tantalum-clad tungsten after hot isostatic pressing 热等静压后钽包钨残余应变的测量
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-01 DOI: 10.3233/jnr-200181
D. Wilcox, P. Loveridge, S. Kabra, T. Lee, J. Moor, D. Jenkins
Tantalum-clad tungsten targets are a popular choice for spallation neutron production, due to the combination of high neutron yield and corrosion resistance. Such targets typically use the Hot Isostatic Press (HIP) process to bond the cladding to the core; this produces a strong bond but also introduces large residual stresses in the target and cladding. This is of particular interest at the ISIS neutron source, because cladding breaches are currently believed to limit the lifetime of ISIS TS2 targets. Two different and complementary methods were used to measure the residual strain in a tantalum-clad tungsten strip manufactured using the same HIP process as ISIS targets. The strip was produced with deliberately asymmetric cladding, causing it to deflect in proportion to the residual stress. FEA simulations were used to back-calculate the stress from the measured deflection. The strip was then placed on the ISIS instrument ENGIN-X, which allowed detailed through-thickness strain profiles to be measured via neutron diffraction. The results of both methods confirm the presence of large residual strains, and agree reasonably well with FEA simulations of the cladding process.
钽包覆钨靶具有高中子产率和耐腐蚀性,是产生散裂中子的常用靶材。这种靶材通常使用热等静压(HIP)工艺将包层粘合到芯上;这产生了牢固的粘结,但也在靶材和包层中引入了较大的残余应力。这在ISIS中子源中是特别有趣的,因为目前认为包层断裂会限制ISIS TS2目标的寿命。采用两种不同的互补方法测量了采用与ISIS靶材相同的HIP工艺制造的钽包覆钨带的残余应变。带材是故意用不对称包层制造的,使其与残余应力成比例地偏转。利用有限元模拟反演了实测挠度的应力。然后将该条带放置在ISIS仪器engine - x上,通过中子衍射可以测量详细的全厚度应变分布图。两种方法的结果都证实了熔覆过程中存在较大的残余应变,并与有限元模拟结果吻合较好。
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引用次数: 0
Heat transfer analysis study for the design of the New Polychromatic Beam Neutron Reflectometer CANDOR (Chromatic Analysis Neutron Diffractometer Or Reflectometer). 设计新型多色束中子反射计CANDOR(彩色分析中子衍射计或反射计)的传热分析研究
IF 1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-01 DOI: 10.3233/jnr-200173
Lior Uzan, Juscelino B Leão, Christoph Brocker, Daniel Mattes, Tanya Dax

A newly developed polychromatic beam neutron reflectometer CANDOR (Chromatic Analysis Neutron Diffractometer Or Reflectometer) on NG-1 at the NIST Center for Neutron research (NCNR) utilizes a wavelength-sensitive neutron detector consisting of 324 analyzing highly-oriented pyrolytic graphite (HOPG) crystals positioned sequentially in rows. Known for having a small thermal diffuse scattering cross section, HOPG crystals can lead to low signal-to-noise ratios in wavelength-sensitive detectors such as CANDOR. Even though it is possible to mathematically separate the desired signal from thermal diffuse scattering; by cooling the detector array of HOPG crystals in order to minimize the Debye Waller effect generates a better solution to this problem. In this heat transfer analysis study we show, within the instrument design constrains and thermodynamic considerations, technical feasibility and test results for the development of the New Polychromatic Beam Neutron Reflectometer CANDOR (Chromatic Analysis Neutron Diffractometer Or Reflectometer) at the NIST Center for Neutron Research.

NIST中子研究中心(NCNR)在NG-1上新开发的多色束中子反射仪CANDOR(色分析中子衍射仪或反射仪)利用由324个波长敏感中子探测器组成的高取向热解石墨(HOPG)晶体依次排列。众所周知,HOPG晶体具有小的热漫射散射截面,可以在波长敏感的探测器(如CANDOR)中导致低信噪比。即使在数学上可以从热扩散散射中分离出期望的信号;通过对探测器阵列的HOPG晶体进行冷却,使德拜-沃勒效应最小化,可以较好地解决这一问题。在这项传热分析研究中,我们展示了在仪器设计限制和热力学考虑的情况下,NIST中子研究中心开发的新型多色束中子反射计CANDOR(色分析中子衍射计或反射计)的技术可行性和测试结果。
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引用次数: 0
Assessment of shutdown dose rates at the ESS target cooling system using SCALE6.2 使用SCALE6.2评估ESS目标冷却系统的关闭剂量率
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-01 DOI: 10.3233/jnr-190136
A. Chambon, E. Klinkby, Leif Emås, B. Lauritzen
The production of high-energy neutrons at the European Spallation Source through the spallation process may cause an erosion of the tungsten target. The eroded particles could be released into the target helium cooling system which contains four kind of filters. Among them, the auxiliary filters called “getters” are designed to capture volatile elements and remaining dust. In this work, the ORNL’s SCALE6.2 modelling and simulation suite for nuclear safety analysis is applied to assess shutdown dose rates and determine if added shielding and/or robotic arms are needed for their maintenance. SCALE6.2 is well adapted to treat this problem as it allows for isotope selection regarding source term calculation. Dose rates are determined by an ORIGEN2 source term and a MAVRIC shielding sequence calculation. As SCALE6.2 is non-standard software for ESS, the results are verified against MCNP, which is the baseline tool for neutronics analysis at ESS. Dose rate calculations show that additional shielding and/or robot arm are not needed to remove the getters after 3 months of cooling time, following 5400 h of operation at 5 MW beam power. At a distance of 1 mm from the getter, the dose rate is 0.2 mSv/h in the most conservative estimation.
欧洲散裂源通过散裂过程产生的高能中子可能导致钨靶的侵蚀。被侵蚀的颗粒可以被释放到目标氦冷却系统中,该系统包含四种过滤器。其中,被称为“捕集器”的辅助过滤器用于捕获挥发性元素和剩余粉尘。在这项工作中,ORNL的SCALE6.2核安全分析建模和仿真套件被用于评估关闭剂量率,并确定是否需要增加屏蔽和/或机械臂来维护它们。SCALE6.2很好地适应了处理这个问题,因为它允许在源项计算方面进行同位素选择。剂量率由ORIGEN2源项和MAVRIC屏蔽序列计算确定。由于SCALE6.2是ESS的非标准软件,结果与MCNP进行了验证,MCNP是ESS中子分析的基准工具。剂量率计算表明,在5兆瓦束流功率下运行5400小时,经过3个月的冷却时间后,不需要额外的屏蔽和/或机械臂来移除吸收器。在距吸气器1mm处,最保守的估计剂量率为0.2 mSv/h。
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引用次数: 0
Non-static surfaces in MCNPX: The chopper extension1 MCNPX中的非静态表面:斩波扩展1
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-01 DOI: 10.3233/jnr-200148
K. Grammer, F. Gallmeier, E. Iverson
Rotating objects, such as choppers, are common components of a neutron beamline, and the motion of these components is not described in the static geometry of an MCNPX model. The special case of non-static surfaces for rotation about a stationary point in space has been developed for MCNPX. In addition, velocity dependent kinematics due to the motion of the medium have been implemented. This implementation allows for the simulation of rotating objects at speeds comparable to the velocity of cold neutrons. Applications of the chopper extension will be discussed, including the direct simulation of a bandwidth chopper system, the thermalization of neutrons inside a spinning material, and the discussion of the implementation of a spinning single crystal.
旋转物体,如切刀,是中子束线的常见组成部分,这些组成部分的运动在MCNPX模型的静态几何中没有描述。为MCNPX开发了非静态曲面绕空间固定点旋转的特殊情况。此外,由于介质的运动,速度相关的运动学已经实现。这种实现允许以与冷中子速度相当的速度模拟旋转物体。讨论斩波扩展的应用,包括带宽斩波系统的直接模拟,自旋材料内中子的热化,以及自旋单晶的实现。
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引用次数: 0
Shielding development for the VENUS imaging instrument VENUS成像仪屏蔽装置的研制
IF 1.1 Q3 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2020-01-01 DOI: 10.3233/jnr-200164
I. Popova, F. Gallmeier
VENUS is an imaging instrument that will use a broad range of neutron wavelengths, from epithermal to cold, will include enhanced contrast mechanisms, and will offer novel energy-selective imaging techniques that directly connect the structures, properties, and function of complex engineering materials and systems to reveal practical and fundamental answers about their real-world performance. The instrument is to be built at SNS beam line 10 and will face the decoupled poisoned hydrogen moderator. The driving cost for the instrument is the beam line and instrument cave shielding. Initial scoping analyses were performed to estimate thickness and composition of shielding materials for the instrument cave and beam line. In light of the upcoming Proton Power Upgrade (PPU) project, these transport analyses were performed for proton beam on target at 1.3 GeV and 2 MW.
VENUS是一种成像仪器,将使用广泛的中子波长,从超低温到低温,将包括增强的对比机制,并将提供新的能量选择成像技术,直接连接复杂工程材料和系统的结构,性质和功能,以揭示其现实世界性能的实际和基本答案。该仪器将建在SNS束流线10号,将面对解耦的有毒氢慢化剂。仪器的驱动成本主要是波束线和仪器洞穴屏蔽。进行了初步的范围分析,以估计仪器洞穴和波束线屏蔽材料的厚度和组成。鉴于即将到来的质子功率升级(PPU)项目,这些输运分析是在1.3 GeV和2 MW的目标质子束上进行的。
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引用次数: 0
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Journal of Neutron Research
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