标题： 欧洲散裂中子源的通用指南概念 显示英文标题

标题： Generic guide concepts for the European Spallation Source

摘要： 从中子束传输的角度来看，欧洲散裂中子源（ESS）的建设面临许多挑战：散裂源被指定为由5兆瓦质子束驱动，每个质子的能量为2吉电子伏特，但相对于测量信号的仪器背景抑制要求在10$^{-6}$到10$^{-8}$之间变化。预计在靶中会产生大量能量粒子，特别是高于20兆电子伏特的粒子，必须进行过滤，以确保束流线的安全、运行和提供低背景的高质量测量。我们提出了适用于短型和中型仪器的通用中子导管，这些导管在最低成本下实现了良好的性能。为了避免直接视线到源，要么第一个点不在视线范围内，要么两者都在掩体（20米）内，以最小化屏蔽成本。这些导管几何形状被视为定义在ESS上建造仪器标准的基础。它们用于寻找共性并开发解决常见问题的原则和解决方案。最后，我们报告了采用过照度概念来被动减轻随机对准偏差损失的影响，并指出过照度应在关键位置谨慎使用以达到效果。对于更广泛的对准问题，可能需要更直接的主动方法。 显示英文摘要

摘要： The construction of the European Spallation Source (ESS) faces many challenges from the neutron beam transport point of view: The spallation source is specified as being driven by a 5 MW beam of protons, each with 2 GeV energy, and yet the requirements in instrument background suppression relative to measured signal vary between 10$^{-6}$ and 10$^{-8}$. The energetic particles, particularly above 20 MeV, which are expected to be produced in abundance in the target, have to be filtered in order to make the beamlines safe, operational and provide good quality measurements with low background. We present generic neutron guides of short and medium length instruments which are optimized for good performance at minimal cost. Direct line of sight to the source is avoided twice, with either the first point out of line of sight or both being inside the bunker (20\,m) to minimize shielding costs. These guide geometries are regarded as a baseline to define standards for instruments to be constructed at ESS. They are used to find commonalities and develop principles and solutions for common problems. Lastly, we report the impact of employing the over-illumination concept to mitigate losses from random misalignment passively, and that over-illumination should be used sparingly in key locations to be effective. For more widespread alignment issues, a more direct, active approach is likely to be needed.