Fundamental Research in SRF at TRIUMF

优化和理解射频性能的研究主要集中在用于电子加速的1.3 GHz椭圆形腔上。新一波强子SRF直线加速器正在研制中，它将使用连续波(CW)射频功率工作。强子加速器的腔体是非椭圆形结构，使用的是瞬变电磁加速模式，必须加速的粒子速度范围很广，一般为光速的5%~80%，射频频率一般为100 MHz~700 MHz。*我们的工作使我们确信，理解新工艺和新材料的性能需要研究材料的微观行为以及全谐振腔结构的性能。这项提案的PI使用了之前的Discovery补助金和RTI资金来支持学生和设备安装射频感应炉，为多个频率的射频低温测试寻找两个同轴腔体，并利用muSR探索NB和新材料的性能(T.Junginger等人)。2018年8月21,032002)。此外，RTI资金已用于购买新的Beta核磁共振光束线的设备，以进一步研究SRF材料。所有设备都是为支持以学生为基础的研究项目而设计的。*这里申请的资金将使我们能够利用TRIUMF和不列颠哥伦比亚大学的专业知识和设备，以及从内部和通过外部合作者获得的材料，继续在微观层面探索材料。特别是，我们将继续进行批量测试的musr测量，并完成新的光谱仪到-核磁共振设施，以允许在地表进行测试场抑制。该设备将允许测量样品中迈斯纳状态极限附近的磁场穿透，作为穿过伦敦层深度的函数。贝塔核磁共振深度剖面诊断将提供世界上独一无二的测试基础设施，为层状结构的有效性提供重要答案，并为SRF研究打开新的机会。*我们的全谐振器研究计划将主要专注于优化非椭圆同轴腔(TEM)的性能。腔体的大小允许进行批量热处理，包括在射频感应炉中掺杂。在本研究过程中，我们建议在同轴谐振器上安装H-MAP系统和T-MAP系统，并在低温恒温器上安装多轴亥姆霍兹线圈，以研究同轴几何中的磁通排出。射频感应炉还将允许在样品上形成Nb3Sn涂层，然后再在单电池椭圆腔和透射电子显微镜模式腔上进行。后者将能够测试作为射频频率和射频场函数的Nb3Sn的有效性。*申请这笔资金是为了实现发现科学。在探索过程中，学生和年轻的专业人员将在寻求开创性问题的同时接受培训。********

Studies to optimize and understand rf performance have been focused on elliptical 1.3GHz cavities for electron acceleration. A new wave of hadron SRF linear accelerators are being developed that would operate with continuous wave (cw) rf power. The cavities for hadron accelerators are non-elliptical structures utilizing the TEM accelerating mode and must accelerate a wide range of particle velocities from 5% to ~80% the speed of light and with rf frequencies ranging from 100MHz to 700MHz typically. ******Our work has convinced us that an understanding of the performance of new processes and new materials requires the ability to study both the microscopic behaviour of materials as well as the performance of full resonator structures. The PI on this proposal has used a previous Discovery grant and RTI funds to support students and equipment to install an rf induction oven, to source two coaxial cavities for rf cryogenic testing at multiple frequencies and to explore the performance of Nb and new materials with muSR (T. Junginger et al. PRAB 2018 21, 032002). In addition RTI funds have been used to purchase equipment for a new betaNMR beamline to further study SRF materials. All the equipment is geared to support student based research programs. ******The funds requested here will allow us to continue to explore materials at the microscopic level utilizing the expertise and equipment at TRIUMF and the University of British Columbia and materials sourced both internally and through external collaborators. In particular we will continue muSR measurements for testing in the bulk and complete the new spectrometer to the -NMR facility to allow testing field suppression at the surface. The facility would allow measurements of the magnetic field penetration in the sample near the limits of the Meissner state as a function of depth through the London layer. The beta-NMR depth profile diagnostic would offer a test infrastructure unique in the world for providing important answers to the effectiveness of layered structures and open new opportunities in SRF research.******Our program of full resonators study will focus mainly on optimizing the performance of non-elliptical coaxial cavities (TEM). The cavities are sized to allow bulk heat treatments including doping in the rf induction oven. During the course of this study we propose to outfit the coaxial resonators with an H-map system and T-map system and the cryostat with multi-axis Helmholtz coils to study flux expulsion in the coaxial geometry. The rf induction oven would also allow development of Nb3Sn coatings on samples then single cell elliptical and TEM mode cavities. The latter would enable testing the effectiveness of Nb3Sn as a function of rf frequency and rf field. ******The funds are requested to enable discovery science. During the quest students and young professionals will be trained while pursuing ground breaking questions. ********