A prototype quasi-parasitic thermal neutron beam monitor based on isotropic neutron scattering from a thin natural vanadium foil and standard ${}^3$He proportional counters is conceptualized, designed, simulated, calibrated, and commissioned. The European Spallation Source designed to deliver the highest integrated neutron flux originating from a pulsed source is currently under construction in Lund, Sweden. The effort to investigate a vanadium-based neutron beam monitor was triggered by a list of requirements for Beam Monitors permanently placed in the ESS neutron beams in order to provide reliable monitoring at complex beamlines: low attenuation, linear response over a wide range of neutron fluxes, near to constant efficiency for neutron wavelengths in a range of 0.6-10~, calibration stability and the possibility to place the system in vacuum are all desirable characteristics. The scattering-based prototype, employing a natural vanadium foil and standard proportional counters, was investigated at the V17 and V20 neutron beamlines of the Helmholtz-Zentrum in Berlin, Germany, in several different geometrical configurations of the proportional counters around the foil. Response linearity is successfully demonstrated for foil thicknesses ranging from 0.04 mm to 3.15 mm. Attenuation lower than 1% for thermal neutrons is demonstrated for the 0.04 mm and 0.125 mm foils. The geometries used for the experiment were simulated allowing for absolute flux calibration and establishing the possible range of efficiencies for various designs of the prototype. The operational flux limits for the beam monitor prototype were established as a dependency of the background radiation and prototype geometry. The herein demonstrated prototype monitors can be employed for neutron intensities ranging from ${10}^3-{10}^{10}$~n/s. \begin{acronym} \end{acronym …

中文翻译：

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钒基中子束监测仪

基于从薄天然钒箔到标准品的各向同性中子散射的准寄生热中子束监测器原型 ${}^3$他对比例计数器进行了概念化，设计，模拟，校准和调试。欧洲散裂源旨在提供源自脉冲源的最高综合中子通量，目前正在瑞典隆德进行建设。永久放置在ESS中子束中的束流监测器的一系列要求触发了研究基于钒的中子束流监测器的工作，以便在复杂的束流线上提供可靠的监测：低衰减，宽范围的中子通量的线性响应对于中子波长范围在0.6-10之间，接近恒定的效率，校准稳定性以及将系统置于真空中的可能性都是理想的特性。基于散射的原型，采用天然钒箔和标准比例计数器，在德国柏林的Helmholtz-Zentrum的V17和V20中子束线处对箔周围的比例计数器的几种不同几何构造进行了研究。箔厚度范围从0.04 mm到3.15 mm，成功地证明了响应线性。对于0.04 mm和0.125 mm的箔片，热中子的衰减低于1％。模拟了用于实验的几何形状，从而可以进行绝对通量校准，并为原型的各种设计确定了可能的效率范围。建立了光束监控器原型的工作通量极限，这取决于背景辐射和原型几何形状。本文展示的原型监测器可用于中子强度范围为${10}^3-{10}^{10}$〜n / s。\ begin {acronym} \ end {acronym…