Development of Electro-Optic Beam Position Monitors for the Large Hadron Collider

欧洲核子研究中心光束仪器小组和伦敦大学皇家霍洛威学院（RHUL）的合作旨在开发新型光束位置监测器。长期目标是利用电光晶体的快速时间响应，在未来的高亮度大型强子对撞机上建立一个监测螃蟹腔引起的质子束旋转的系统。通过晶体的光的偏振变化是由与通过的带电粒子束的电光（波克尔斯）相互作用引起的。快速检测（lOGHz带宽）从放置在束管两侧的拾取器的光信号，允许在沿ns束的不同位置监测束内粒子的横向偏移。RHUL的博士生将加入这个合作实验项目，开发用于CERN加速器链测试的光学BPM，包括2016年在CERN SPS中安装的EO-BPM原型的测试。学生将评估与电磁模拟比较的初步结果，并将设计扩展到干涉测量配置，以评估潜在的改进灵敏度。在SPS成功测试之前，LHC的EO-BPM原型将被设计和制造，用于RHUL和CERN的基准测试。该职位将在伦敦大学皇家霍洛威学院工作，并有望前往欧洲核子研究中心。该学生将受益于RHUL约翰亚当斯研究所的支持和培训，包括加速器物理讲座，以及新的HL-LHC-UK合作的更广泛网络。

A collaboration between the CERN Beam Instrumentation group and Royal Holloway, University of London (RHUL) aims to develop novel optical Beam Position Monitors. The long term objective is to build a system to monitor proton bunch rotation induced by crab-cavities at the future High Luminosity Large Hadron Collider, by exploiting the fast time response of electro- optic crystals. A change in the polarization of light passing through the crystal is induced by the electro-optic (Pockels) interaction with the passing charged particle bunch. Rapid detection (lOGHz bandwidth) of the optical signals from pick-ups placed on opposite sides of the beam pipe, allow transverse offsets of particles within a bunch to be monitored, at different positions along the ns bunch. The RHUL PhD student will join this collaborative experimental program to develop the optical BPM for tests in the CERN accelerator chain, including tests of a prototype EO-BPM that has been installed during 2016 in the CERN SPS. The student will evaluate initial results in comparison with electromagnetic simulations, and extend the design to an interferometric configuration to assess the potentially improved sensitivity. Pending successful tests at the SPS, a prototype EO-BPM for the LHC will be designed and manufactured for benchtests at RHUL and CERN. The position will be based at Royal Holloway, University of London, and travel to CERN is expected. The student will benefit from the support and training in the RHUL John Adams Institute, including lectures in accelerator physics, and the wider network of the new HL-LHC-UK collaboration.