1. 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

2. Multipactor
Externally driven AWA structures tests at NRL

3. Outline Multipactor suppression in HG structures (simulations)
Grooved structures for multipactor studies

4. 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, (2009)
AAC 2010 O.V. Sinitsyn, G. S. Nusinovich and T. M. Antonsen, Jr.

5. 2D model implementation
SEE energy distribution
+ θ - distribution
C. Vicente, et al. MULCOPIM 2005 Modified Vaughan model

6. Multipactor. Power loss vs gradient
Electron cloud at different times
Multipactor power loss decreases at HG

7. Simplified representation
Ez = 10 MV/m
We emit particles at different phases and monitor their incidence energy and corresponding yield

8. 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, (2007)

9. 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, (2009)

10. Grooved structure design
Ez = 6 MV/m
* CST
Limited by machining capabilities

11. 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

12. 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