High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods
An improved single-cell photonic band-gap (PBG) structure with an inner row of elliptical rods (PBG-E) was tested with high power at a 60 Hz repetition rate at X-band (11.424 GHz), achieving a gradient of 128 MV/m at a breakdown probability of 3.6×10-3 per pulse per meter at a pulse length of 150 n...
| Main Authors: | , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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American Physical Society
2013
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| Online Access: | http://hdl.handle.net/1721.1/78265 https://orcid.org/0000-0001-9813-0177 |
| _version_ | 1811092894971330560 |
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| author | Munroe, Brian James Cook, Alan M. Shapiro, Michael Temkin, Richard J. Dolgashev, Valery A. Laurent, Lisa L. Lewandowski, James R. Yeremian, A. Dian Tantawi, Sami G. Marsh, Roark A. |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Munroe, Brian James Cook, Alan M. Shapiro, Michael Temkin, Richard J. Dolgashev, Valery A. Laurent, Lisa L. Lewandowski, James R. Yeremian, A. Dian Tantawi, Sami G. Marsh, Roark A. |
| author_sort | Munroe, Brian James |
| collection | MIT |
| description | An improved single-cell photonic band-gap (PBG) structure with an inner row of elliptical rods (PBG-E) was tested with high power at a 60 Hz repetition rate at X-band (11.424 GHz), achieving a gradient of 128 MV/m at a breakdown probability of 3.6×10-3 per pulse per meter at a pulse length of 150 ns. The tested standing-wave structure was a single high-gradient cell with an inner row of elliptical rods and an outer row of round rods; the elliptical rods reduce the peak surface magnetic field by 20% and reduce the temperature rise of the rods during the pulse by several tens of degrees, while maintaining good damping and suppression of high order modes. When compared with a single-cell standing-wave undamped disk-loaded waveguide structure with the same iris geometry under test at the same conditions, the PBG-E structure yielded the same breakdown rate within measurement error. The PBG-E structure showed a greatly reduced breakdown rate compared with earlier tests of a PBG structure with round rods, presumably due to the reduced magnetic fields at the elliptical rods vs the fields at the round rods, as well as use of an improved testing methodology. A post-testing autopsy of the PBG-E structure showed some damage on the surfaces exposed to the highest surface magnetic and electric fields. Despite these changes in surface appearance, no significant change in the breakdown rate was observed in testing. These results demonstrate that PBG structures, when designed with reduced surface magnetic fields and operated to avoid extremely high pulsed heating, can operate at breakdown probabilities comparable to undamped disk-loaded waveguide structures and are thus viable for high-gradient accelerator applications. |
| first_indexed | 2024-09-23T15:33:23Z |
| format | Article |
| id | mit-1721.1/78265 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:33:23Z |
| publishDate | 2013 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/782652022-10-02T02:52:40Z High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods Munroe, Brian James Cook, Alan M. Shapiro, Michael Temkin, Richard J. Dolgashev, Valery A. Laurent, Lisa L. Lewandowski, James R. Yeremian, A. Dian Tantawi, Sami G. Marsh, Roark A. Massachusetts Institute of Technology. Department of Physics Massachusetts Institute of Technology. Plasma Science and Fusion Center Munroe, Brian James Cook, Alan M. Shapiro, Michael Temkin, Richard J. An improved single-cell photonic band-gap (PBG) structure with an inner row of elliptical rods (PBG-E) was tested with high power at a 60 Hz repetition rate at X-band (11.424 GHz), achieving a gradient of 128 MV/m at a breakdown probability of 3.6×10-3 per pulse per meter at a pulse length of 150 ns. The tested standing-wave structure was a single high-gradient cell with an inner row of elliptical rods and an outer row of round rods; the elliptical rods reduce the peak surface magnetic field by 20% and reduce the temperature rise of the rods during the pulse by several tens of degrees, while maintaining good damping and suppression of high order modes. When compared with a single-cell standing-wave undamped disk-loaded waveguide structure with the same iris geometry under test at the same conditions, the PBG-E structure yielded the same breakdown rate within measurement error. The PBG-E structure showed a greatly reduced breakdown rate compared with earlier tests of a PBG structure with round rods, presumably due to the reduced magnetic fields at the elliptical rods vs the fields at the round rods, as well as use of an improved testing methodology. A post-testing autopsy of the PBG-E structure showed some damage on the surfaces exposed to the highest surface magnetic and electric fields. Despite these changes in surface appearance, no significant change in the breakdown rate was observed in testing. These results demonstrate that PBG structures, when designed with reduced surface magnetic fields and operated to avoid extremely high pulsed heating, can operate at breakdown probabilities comparable to undamped disk-loaded waveguide structures and are thus viable for high-gradient accelerator applications. United States. Dept. of Energy. High Energy Physics Division (Contract DEFG02-91ER40648) 2013-04-03T14:50:27Z 2013-04-03T14:50:27Z 2013-01 2012-08 Article http://purl.org/eprint/type/JournalArticle 1098-4402 http://hdl.handle.net/1721.1/78265 Munroe, Brian J. et al. “High Power Breakdown Testing of a Photonic Band-gap Accelerator Structure with Elliptical Rods.” Physical Review Special Topics - Accelerators and Beams 16.1 (2013). https://orcid.org/0000-0001-9813-0177 en_US http://dx.doi.org/10.1103/PhysRevSTAB.16.012005 Physical Review Special Topics - Accelerators and Beams Creative Commons Attribution 3.0 http://creativecommons.org/licenses/by/3.0/ application/pdf American Physical Society APS |
| spellingShingle | Munroe, Brian James Cook, Alan M. Shapiro, Michael Temkin, Richard J. Dolgashev, Valery A. Laurent, Lisa L. Lewandowski, James R. Yeremian, A. Dian Tantawi, Sami G. Marsh, Roark A. High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods |
| title | High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods |
| title_full | High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods |
| title_fullStr | High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods |
| title_full_unstemmed | High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods |
| title_short | High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods |
| title_sort | high power breakdown testing of a photonic band gap accelerator structure with elliptical rods |
| url | http://hdl.handle.net/1721.1/78265 https://orcid.org/0000-0001-9813-0177 |
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