Strong effect of beam coherent scattering ("reflection") in a field of bent crystal is observed in crystal collimation experiments performed with heavy ions and protons at RHIC and started at Tevatron collider. Detailed simulation using Monte Carlo code CATCH is done in order to understand the observations and relate them to the physics of beam coherent scattering in crystal. A.M. Taratin and S.A. Vorobiev predicted the effect of beam "volume reflection" in bent crystals in 1987. The presented data is the first manifestation of this new physical phenomenon in experiment.
The Large Hadron Collider (LHC) uses a multi-stage collimator system to absorb the growing halo of circulating beams to protect and ensure reliable operation of superconducting magnets. A similar system is planned for the Future Circular Collider (FCC). In anticipation of the LHC operation with high luminosity, research is being conducted to improve the collimation system. Studies have shown that one of the solutions to improve beam collimation is to use channeling in a short curved crystal, which acts as a primary collimator, throwing particles deep into the secondary collimator by channeling…
UA 9实验装置于2009年3月安装在CERN-SPS上，目的是研究惯性模式下的晶体辅助准直。它的基本布局包括硅弯曲晶体作为安装在两个真空容器内的主准直器。一个可移动的60厘米长的钨块位于下游约90度相位提前拦截偏转束。闪烁器、气体电子倍增器室和其他束流损失监测器测量晶体中束晕相互作用引起的核损失率。罗马盆安装在偏转粒子的路径，并配备了Medipix检测器，以重建撞击束的横向分布。最后，UA 9利用安装在罗马锅附近的LHC准直器原型来帮助设置束流条件并分析偏转束流的效率。本文详细介绍了2010年为研究晶体准直而安装的硬件。
The mean volume reflection angle of a high-energy charged particle passing through a bent crystal is expressed as an integral involving the effective interplanar potential over a single crystal period. Implications for positively and negatively charged particles, and silicon crystal orientations (110) and (111) are discussed. A generic next-to-leading-order expansion in the ratio $E/R$ of the particle energy $E$ to the crystal bending radius $R$ is given. For positively charged particles, the dependence of the mean volume reflection angle on $E/R$ proves to be approximately linear, whereas for…
X-ray free electron laser oscillators (XFELO) is future light source to produce fully coherent hard X-ray pulses. The X-rays circulate in an optical cavity built from multiple Bragg reflecting mirrors, which has a high reflectance in a bandwidth of ten meV level. The X-ray crystal mirrors exposed to intense X-ray beams in the cavity are subjects to thermal deformations that shift and distort the Bragg reflection. Therefore, the stability of the XFELO operation relies on the abilities of mirrors to preserve the Bragg reflection under such heat load. A new approach was used to analyze the heat l…
Experimental results and simulation models show that crystals might play a relevant role for the development of new generations of high-energy and high-intensity particle accelerators and might disclose innovative possibilities at existing ones. In this paper we describe the most advanced manufacturing techniques of crystals suitable for operations at ultra-high energy and ultra-high intensity particle accelerators, reporting as an example of potential applications the collimation of the particle beams circulating in the Large Hadron Collider at CERN, which will be upgraded through the additio…
