Thermionic cathode gridded electron gun for RF linacs

下一代安全直线加速器可能会以更短的脉冲和更高的重复频率运行，以改善材料分离、单光子计数或使反向散射X射线能够被使用。然而，还不存在这样的商业直线加速器，然而，通过利用高梯度加速器中采用的RF设计方法和技术并利用现有的替代RF源，可以实现这样的直线加速器。一个关键的技术，将使短脉冲操作将是纳入一个栅极的负离子阴极电子枪调制的电子束。本计画旨在设计一种应用于射频直线加速器的阴极栅极电子枪。栅格电子枪设计将由斯特拉斯克莱德大学与TMD技术有限公司合作开发，TMD技术有限公司在为高功率微波放大器提供类似电子束源方面有着良好的记录。学生将在Hayes Middlesex的TMD技术有限公司进行为期六个月的实习，以融入设计知识和对网格结构的理解，从而实现高占空比操作，同时最大限度地减少光束拦截。TMD技术有限公司还将向学生提供高压电源和隔离的专业知识，这些专业知识是向电网施加电压以调制光束所需的。此外，学生将参与升级和运行Cockcroft研究所现有的RF直线加速器设施，以测试最新的X射线探测器的发展，并了解任何新的直线加速器的要求。

The next generation of security linacs will likely operate with shorter pulses and higher repetition frequencies to improve material separation, single photon counting or to enable backscattered X-rays to be employed. However no such commercial linac exists already, however by utilising RF design methodology and techniques employed in high gradient accelerators and utilising existing alternative RF sources such a linac could be realised. A crucial technology that will enable short pulse operation will be the incorporation of a gridded thermionic cathode electron gun to modulate the electron beam. This project aims to design and model a thermionic cathode gridded electron gun for the RF linac. The gridded electron gun design will be developed by the University of Strathclyde in collaboration with TMD Technologies Ltd who have a track record of providing similar electron beam sources for high power microwave amplifiers. The student will take a six month placement with TMDs Technologies Ltd, Hayes Middlesex to incorporate in the design knowledge and understanding of the grid structure to enable high duty cycle operation while minimising beam interception. TMD Technologies Ltd will also make available to the student expertise of high voltage power supplies and isolation needed to apply voltage to the grid to modulate the beam. In addition the student would be involved in upgrading and running the Cockcroft Institute's existing RF linac facility to test the latest X-ray detector developments and to understand the requirements of any new linacs.