Experimental high gradient testing of a 17.1 GHz photonic band-gap accelerator structure
Name
Experimental high.pdf
Size
2.14 MB
Format
Adobe PDF
Checksum (MD5)
8ba616221d265622067808241877fc44
Author(s)
Munroe, Brian James
Zhang, Jiexi
Xu, Haoran
Shapiro, Michael
Temkin, Richard J
Date Issued
March 2016
Journal
Physical Review Accelerators and Beams
Publisher
American Physical Society
Citation
Munroe, Brian J. et al. “Experimental High Gradient Testing of a 17.1 GHz Photonic Band-Gap Accelerator Structure.” Physical Review Accelerators and Beams 19, 3 (March 2016): 031301
Version
Final published version
Abstract
We report the design, fabrication, and high gradient testing of a 17.1 GHz photonic band-gap (PBG) accelerator structure. Photonic band-gap (PBG) structures are promising candidates for electron accelerators capable of high-gradient operation because they have the inherent damping of high order modes required to avoid beam breakup instabilities. The 17.1 GHz PBG structure tested was a single cell structure composed of a triangular array of round copper rods of radius 1.45 mm spaced by 8.05 mm. The test assembly consisted of the test PBG cell located between conventional (pillbox) input and output cells, with input power of up to 4 MW from a klystron supplied via a TM₀₁ mode launcher. Breakdown at high gradient was observed by diagnostics including reflected power, downstream and upstream current monitors and visible light emission. The testing procedure was first benchmarked with a conventional disc-loaded waveguide structure, which reached a gradient of 87 MV/m at a breakdown probability of 1.19×10⁻¹ per pulse per meter. The PBG structure was tested with 100 ns pulses at gradient levels of less than 90 MV/m in order to limit the surface temperature rise to 120 K. The PBG structure reached up to 89 MV/m at a breakdown probability of 1.09×10⁻¹ per pulse per meter. These test results show that a PBG structure can simultaneously operate at high gradients and low breakdown probability, while also providing wakefield damping.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Terms of Use
Creative Commons Attribution 3.0 Unported license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/PhysRevAccelBeams.19.031301
