Experimental Materials Research for Photoelectron Sources

该项目将专注于光电阴极应用的金属半导体材料的制造和测试，以确定优化材料性能的材料和制备技术。该项目有两个研究项目，使用；-以实验室为基础的仪器，用于制备、制造和表征适合于光阴极的材料，包括调试一种新的沉积系统，以生长薄的碱锑化物/碲化物层。-现有的金属光电阴极制备设施和新的生长系统，用于生产用于VELA电子注入器测试的阴极，使用广泛的机器诊断套装来测量横向和纵向光束特性。该学生将在研究期间加入ASTeC在Daresbury国家实验室的加速器物理小组。该项目是ASTeC之前进行的研究的延伸，该研究在横向能量扩散光谱仪（TESS）的静电建模和光电阴极材料横向和纵向能量分布的测量方面取得了重大成果。在项目的第一年，学生将熟悉现有的表面分析设备，并为新的碱锑/碲生长设备的调试做出贡献。补充数据也将使用TESS仪器收集。在项目的后期，将生产光电阴极，用于VELA加速器的测试，并进行测试前和测试后的表征。加速器内测试将使用现有的诊断套件进行，包括用于测量能量和能量扩散的光谱仪线，用于测量发射度的四轴扫描和用于束长（因此响应时间）表征的横向偏转腔。拟议的项目有能力产生相当大的影响。所产生的数据将为支持VELA/CLARA加速器的操作提供宝贵的投入，特别是有助于建立稳定可靠的操作条件。此外，研究结果将有助于英国XFEL和FCC原型的电子注入器的持续规范，发展专业知识并降低与加速器关键子系统相关的风险。最终，这项工作将有助于国际上正在进行的理解和提高光电阴极性能的努力，这对FEL应用和高能物理机器都很重要。

This project will focus on the fabrication and testing of metal-semiconductor materials for photocathode applications, to identify materials and preparation techniques that optimise material performance. The project has two strands to the research programme, using; - laboratory-based instrumentation to prepare, fabricate and characterise materials suitable for photocathodes, including the commissioning of a new deposition system to growth thin alkali antimonide/telluride layers. - existing metal photocathode preparation facility and the new growth system to produce cathodes for testing in the VELA electron injector, using the extensive suite of machine diagnostics to measure transverse and longitudinal beam properties. The student will join ASTeC's Accelerator Physics group at Daresbury National Laboratory for the duration of the research. This project is an extension of previous research undertaken in ASTeC which led to significant results both in electrostatic modelling of the Transverse Energy Spread Spectrometer (TESS) and measurement of transverse and longitudinal energy distributions of photocathode materials. In the first year of the project the student will familiarise themselves with the existing surface analysis equipment and contribute to the commissioning of the new alkali antimonide/telluride growth facility. Complementary data will also be collected using the TESS instrument. In the latter part of the project photocathodes will be produced for testing in the VELA accelerator with pre- and post-testing characterisation. In-accelerator testing will be carried out using the existing suite of diagnostics, including the spectrometer line for measuring energy and energy spread, quad scans for emittance measurements and the transverse deflecting cavity for bunch length (and hence response time) characterisation. The proposed project has the capacity to generate considerable impact. The data generated will provide invaluable input to support VELA/CLARA accelerator operations, in particular contributing to the establishment of stable and reliable operating conditions. In addition, the results will contribute to the on-going specification of the electron injector for the proposed UK XFEL and FCC prototype, developing the expertise and reducing the risk associated with this critical sub-system of the accelerator. Ultimately, the work will contribute to the ongoing international effort to understand and improve photocathode performance, which is important for both FEL applications and High Energy Physics machines.