Multipactor Studies Sergey Antipov1,2, C. Jing1,2, P. Schoessow1, A. Kanareykin1, Bin Feng2,3, John Power2, Wei Gai2 1Euclid Techlabs LLC 2Argonne Wakefield Accelerator Facility 3Illinois Institute of Technology US High Gradient Research Collaboration Workshop 2011 2/9/2011
Multipactor Externally driven AWA structures tests at NRL
Outline Multipactor suppression in HG structures (simulations) Grooved structures for multipactor studies
2D simulation University of Maryland model: non-stationary two-dimensional simulation where DC field is taken into account self-consistently Benchmarked with ANL – NRL dielectric loaded accelerating structure measurements O. V. Sinitsyn, G. S. Nusinovich and T. M. Antonsen., Phys. Plasmas, 16, 073102 (2009) AAC 2010 O.V. Sinitsyn, G. S. Nusinovich and T. M. Antonsen, Jr.
2D model implementation SEE energy distribution + θ - distribution C. Vicente, et al. MULCOPIM 2005 Modified Vaughan model
Multipactor. Power loss vs gradient Electron cloud at different times Multipactor power loss decreases at HG
Simplified representation Ez = 10 MV/m We emit particles at different phases and monitor their incidence energy and corresponding yield
High gradient case Ez = 150 MV/m We are developing a Monte-Carlo simulation based on this idea similar to L. Wu, L.K. Ang Physics of Plasmas 14, 013105 (2007)
Progress on grooved structure development for multipactor studies Grooved structure example: Changing the surface profile by periodically grooving has been found to obviously increase the transmitted power in S-band HPM window breakdown experiment C. Chang et al. J. Appl. Phys. 105, 123305 (2009)
Grooved structure design Ez = 6 MV/m * CST Limited by machining capabilities
Quartz grooved tubes for MP studies Longitudinal Transverse we are set to test ~ 10 different configurations: groove type groove dimension structure length TiN coating Matching sections are designed and being manufactured
summary Multipactor simulation approach is being developed for high gradient regimes (100+ MV/m). It suggests a reduction in MP power loss. We designed and manufactured several grooved structures and they are being prepared for the high power tests