IPAC2015 - List of Authors (Munroe, B.J.)

Paper	Title	Page
WEPWA061	High-Gradient Testing of Metallic Photonic Band-gap (PBG) and Disc-Loaded Waveguide (DLWG) Structures at 17 GHz	2643
	B.J. Munroe, M.A. Shapiro, R.J. Temkin, J.X. Zhang MIT/PSFC, Cambridge, Massachusetts, USA
	Funding: This work supported by the DOE, Office of High Energy Physics, Grant No. DE-SC0010075 Photonic Band-gap (PBG) structures continue to be a promising area of research for future accelerator structures. Previous experiments at 11 GHz have demonstrated that PBG structures can operate at high gradient and low breakdown probability, provided that pulsed heating is controlled. A metallic single-cell standing-wave PBG structure has been tested at 17 GHz at MIT to investigate how breakdown probability scales with frequency in these structures. A single-cell standing-wave disc-loaded waveguide (DLWG) was also tested at MIT as a reference structure. The PBG structure achieved greater than 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.1 10-1 /pulse/m. The DLWG structure achieved 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.2 10-1 /pulse/m, the same as the PBG structure within experimental error. These tests were conducted at the MIT structure test stand, and represent the first long-pulse breakdown testing of accelerator structures above X-Band.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA061
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WEPWA062	Design and High-Power Testing of a Hybrid Photonic Band-Gap (PBG) Accelerator Structure at 17 GHz	2646
	J.X. Zhang, A.M. Cook, B.J. Munroe, M.A. Shapiro, R.J. Temkin, H. Xu MIT/PSFC, Cambridge, Massachusetts, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics under Award Number DE-SC0010075. An overmoded hybrid Photonic Band Gap (HPBG) structure used as an accelerator cavity has been theoretically designed and high power tested at 17.1 GHz. The HPBG structure consists of a triangular lattice of dielectric (sapphire) and metallic (copper) rods. Due to the frequency selectivity, the hybrid PBG cavity can be operated in a TM02 mode. The maximum surface fields are on the triple point of the innermost row of the sapphire rods. The relatively high value of the surface fields resulted in a high breakdown rate (BDR) at a low gradient in the HPBG structure. Breakdown damage on the triple point edge and the metallization of copper onto the sapphire surface have been observed in the post-testing images. An improved HPBG design, that reduces the peak fields, has been developed. It will be built and tested in an effort to improve the HPBG performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA062
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

High-Gradient Testing of Metallic Photonic Band-gap (PBG) and Disc-Loaded Waveguide (DLWG) Structures at 17 GHz

2643

B.J. Munroe, M.A. Shapiro, R.J. Temkin, J.X. Zhang
MIT/PSFC, Cambridge, Massachusetts, USA

Funding: This work supported by the DOE, Office of High Energy Physics, Grant No. DE-SC0010075
Photonic Band-gap (PBG) structures continue to be a promising area of research for future accelerator structures. Previous experiments at 11 GHz have demonstrated that PBG structures can operate at high gradient and low breakdown probability, provided that pulsed heating is controlled. A metallic single-cell standing-wave PBG structure has been tested at 17 GHz at MIT to investigate how breakdown probability scales with frequency in these structures. A single-cell standing-wave disc-loaded waveguide (DLWG) was also tested at MIT as a reference structure. The PBG structure achieved greater than 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.1 *10-1 /pulse/m. The DLWG structure achieved 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.2 *10-1 /pulse/m, the same as the PBG structure within experimental error. These tests were conducted at the MIT structure test stand, and represent the first long-pulse breakdown testing of accelerator structures above X-Band.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA061

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWA062

Design and High-Power Testing of a Hybrid Photonic Band-Gap (PBG) Accelerator Structure at 17 GHz

2646

J.X. Zhang, A.M. Cook, B.J. Munroe, M.A. Shapiro, R.J. Temkin, H. Xu
MIT/PSFC, Cambridge, Massachusetts, USA

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics under Award Number DE-SC0010075.
An overmoded hybrid Photonic Band Gap (HPBG) structure used as an accelerator cavity has been theoretically designed and high power tested at 17.1 GHz. The HPBG structure consists of a triangular lattice of dielectric (sapphire) and metallic (copper) rods. Due to the frequency selectivity, the hybrid PBG cavity can be operated in a TM02 mode. The maximum surface fields are on the triple point of the innermost row of the sapphire rods. The relatively high value of the surface fields resulted in a high breakdown rate (BDR) at a low gradient in the HPBG structure. Breakdown damage on the triple point edge and the metallization of copper onto the sapphire surface have been observed in the post-testing images. An improved HPBG design, that reduces the peak fields, has been developed. It will be built and tested in an effort to improve the HPBG performance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA062

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)