IPAC2016 - List of Authors (Hogan, M.J.)

Paper	Title	Page
MOPMW040	Electron Beam Excitation of a Surface Wave in mm-Wave Open Accelerating Structures	494
	M. Dal Forno, G.B. Bowden, C.I. Clarke, V.A. Dolgashev, M.J. Hogan, D.J. McCormick, A. Novokhatski, B.D. O'Shea, S.G. Tantawi, S.P. Weathersby SLAC, Menlo Park, California, USA B. Spataro INFN/LNF, Frascati (Roma), Italy
	Funding: Work supported by the US DOE under contract DE-AC02-76SF00515. As part of research on the physics of rf breakdowns we performed experiments with high gradient traveling-wave mm-wave accelerating structures. The accelerating structures are open, composed of two identical halves separated by an adjustable gap. The electromagnetic fields are excited by an ultra-relativistic electron beam. We observed that a confined travelling-wave mode exists in half of the accelerating structure. The experiments were conducted at FACET facility at SLAC National Accelerator Laboratory. Depending on the gap width, the accelerating structure had beam-synchronous frequencies that vary from 90 to 140 GHz. When we opened the gap by more than half wavelength the synchronous wave remains trapped. Its behavior is consistent with the so called "surface wave". We characterized this beam-wave interaction by several methods: measurement of the radiated rf energy with the pyro-detector, measurement of the spectrum with an interferometer, measurement of the beam deflection by using the beam position monitors and profile monitor.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW040
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MOPMW041	Measurements of RF Breakdowns in Beam Driven mm-Wave Accelerating Structures	497
	M. Dal Forno, G.B. Bowden, C.I. Clarke, V.A. Dolgashev, M.J. Hogan, D.J. McCormick, A. Novokhatski, S.G. Tantawi, S.P. Weathersby SLAC, Menlo Park, California, USA B. Spataro INFN/LNF, Frascati (Roma), Italy
	Funding: Work supported by the US DOE under contract DE-AC02-76SF00515 We studied the physics and properties of rf breakdowns in high gradient traveling-wave accelerating structures at 100 GHz. The structures are open, made of two halves with a gap in between. The rf fields were excited in the structure by an ultra-relativistic electron beam generated by the FACET facility at the SLAC National Accelerator Laboratory. We observed rf breakdowns generated in the presence of GV/m scale electric fields. We varied the rf fields excited by the FACET bunch by moving structure relative to the beam and by changing the gap between structure halves. Reliable breakdowns detectors allowed us to measure the rf breakdown rate at these different rf parameters. We measured radiated rf energy with a pyro-detector. When the beam was off-axis, we observed beam deflection in the beam position monitors and on the screen of a magnetic spectrometer. The measurements of the deflection allowed us to verify our calculation of the accelerating gradient.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW041
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TUOBB02	FACET-II Accelerator Research with Beams of Extreme Intensities	1067
	V. Yakimenko, Y. Cai, C.I. Clarke, S.Z. Green, C. Hast, M.J. Hogan, N. Lipkowitz, N. Phinney, G.R. White, G. Yocky SLAC, Menlo Park, California, USA
	In 2016, the second phase of SLAC's x-ray laser, the LCLS-II, will begin to use part of the tunnel occupied by FACET, and the world's only multi-GeV facility for advanced accelerator research will cease operation. FACET-II is a new test facility to provide DOE with the unique capability to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. FACET-II is an opportunity to build on the decades-long experience developed conducting advanced accelerator R&D at the FFTB and FACET and re-deploy HEP infrastructure in continued service of its mission. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The presentation will discuss FACET-II project status and plans for diverse experimental program.
	Slides TUOBB02 [17.664 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBB02
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TUPOW017	Twin Bunches at the FACET-II	1778
	Z. Zhang TUB, Beijing, People's Republic of China M.J. Hogan, Z. Huang, A. Marinelli SLAC, Menlo Park, California, USA
	Twin electron bunches, generated, accelerated and compressed in the same acceleration bucket, have attracted a lot of interest in the free-electron lasers and wakefield acceleration. The recent successful experiment at the LCLS used twin bunches to generate two-color two x-ray pulses with tunable time delay and energy separation. In this note, we apply the twin bunches to the plasma wakefield acceleration. Numerical simulations show that based on the beamline of the FACET-II, we can generate high-intensity two electron bunches with time delay from ∼ 100 fs to picoseconds, which will benefit the control of high-gradient witness bunch acceleration in a plasma.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW017
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THPPA01	Demonstration of the Hollow Channel Plasma Wakefield Accelerator	3202
SUPSS117	use link to see paper's listing under its alternate paper code
	S.J. Gessner, J.M. Allen, C.I. Clarke, J.-P. Delahaye, J.T. Frederico, S.Z. Green, C. Hast, M.J. Hogan, N. Lipkowitz, M.D. Litos, B.D. O'Shea, D.R. Walz, V. Yakimenko, G. Yocky SLAC, Menlo Park, California, USA E. Adli, C.A. Lindstrøm University of Oslo, Oslo, Norway W. An, C.E. Clayton, C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi UCLA, Los Angeles, California, USA S. Corde, A. Doche LOA, Palaiseau, France W. Lu TUB, Beijing, People's Republic of China
	Funding: Work supported by DOE contract DE-AC02-76SF00515. Over the past decade, there has been enormous progress in the field of beam and laser-driven plasma acceleration of electron beams. However, in order for plasma wakefield acceleration to be useful for a high-energy e⁺e^- collider, we need a technique for accelerating positrons in plasma as well. This is a unique challenge, because the plasma responds differently to electron and positron beams, with plasma electrons being pulled through the positron beam and creating a non-linear focusing force. Here, we demonstrate a technique called hollow channel acceleration that symmetrizes the wakefield response to beams of either charge. Using a transversely shaped laser pulse, we create an annular plasma with a fixed radius of 200 μm. We observe the acceleration of a positron bunch with energies up to 33.4 MeV in a 25 cm long channel, indicating an effective gradient greater than 100 MeV/m. This is the first demonstration of a technique that way be used for staged acceleration of positron beams in plasma.
	Slides THPPA01 [5.647 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPPA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Electron Beam Excitation of a Surface Wave in mm-Wave Open Accelerating Structures

494

M. Dal Forno, G.B. Bowden, C.I. Clarke, V.A. Dolgashev, M.J. Hogan, D.J. McCormick, A. Novokhatski, B.D. O'Shea, S.G. Tantawi, S.P. Weathersby
SLAC, Menlo Park, California, USA
B. Spataro
INFN/LNF, Frascati (Roma), Italy

Funding: Work supported by the US DOE under contract DE-AC02-76SF00515.
As part of research on the physics of rf breakdowns we performed experiments with high gradient traveling-wave mm-wave accelerating structures. The accelerating structures are open, composed of two identical halves separated by an adjustable gap. The electromagnetic fields are excited by an ultra-relativistic electron beam. We observed that a confined travelling-wave mode exists in half of the accelerating structure. The experiments were conducted at FACET facility at SLAC National Accelerator Laboratory. Depending on the gap width, the accelerating structure had beam-synchronous frequencies that vary from 90 to 140 GHz. When we opened the gap by more than half wavelength the synchronous wave remains trapped. Its behavior is consistent with the so called "surface wave". We characterized this beam-wave interaction by several methods: measurement of the radiated rf energy with the pyro-detector, measurement of the spectrum with an interferometer, measurement of the beam deflection by using the beam position monitors and profile monitor.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW040

Export •

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

MOPMW041

Measurements of RF Breakdowns in Beam Driven mm-Wave Accelerating Structures

497

M. Dal Forno, G.B. Bowden, C.I. Clarke, V.A. Dolgashev, M.J. Hogan, D.J. McCormick, A. Novokhatski, S.G. Tantawi, S.P. Weathersby
SLAC, Menlo Park, California, USA
B. Spataro
INFN/LNF, Frascati (Roma), Italy

Funding: Work supported by the US DOE under contract DE-AC02-76SF00515
We studied the physics and properties of rf breakdowns in high gradient traveling-wave accelerating structures at 100 GHz. The structures are open, made of two halves with a gap in between. The rf fields were excited in the structure by an ultra-relativistic electron beam generated by the FACET facility at the SLAC National Accelerator Laboratory. We observed rf breakdowns generated in the presence of GV/m scale electric fields. We varied the rf fields excited by the FACET bunch by moving structure relative to the beam and by changing the gap between structure halves. Reliable breakdowns detectors allowed us to measure the rf breakdown rate at these different rf parameters. We measured radiated rf energy with a pyro-detector. When the beam was off-axis, we observed beam deflection in the beam position monitors and on the screen of a magnetic spectrometer. The measurements of the deflection allowed us to verify our calculation of the accelerating gradient.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW041

Export •

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

TUOBB02

FACET-II Accelerator Research with Beams of Extreme Intensities

1067

V. Yakimenko, Y. Cai, C.I. Clarke, S.Z. Green, C. Hast, M.J. Hogan, N. Lipkowitz, N. Phinney, G.R. White, G. Yocky
SLAC, Menlo Park, California, USA

In 2016, the second phase of SLAC's x-ray laser, the LCLS-II, will begin to use part of the tunnel occupied by FACET, and the world's only multi-GeV facility for advanced accelerator research will cease operation. FACET-II is a new test facility to provide DOE with the unique capability to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. FACET-II is an opportunity to build on the decades-long experience developed conducting advanced accelerator R&D at the FFTB and FACET and re-deploy HEP infrastructure in continued service of its mission. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The presentation will discuss FACET-II project status and plans for diverse experimental program.

Slides TUOBB02 [17.664 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBB02

Export •

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

TUPOW017

Twin Bunches at the FACET-II

1778

Z. Zhang
TUB, Beijing, People's Republic of China
M.J. Hogan, Z. Huang, A. Marinelli
SLAC, Menlo Park, California, USA

Twin electron bunches, generated, accelerated and compressed in the same acceleration bucket, have attracted a lot of interest in the free-electron lasers and wakefield acceleration. The recent successful experiment at the LCLS used twin bunches to generate two-color two x-ray pulses with tunable time delay and energy separation. In this note, we apply the twin bunches to the plasma wakefield acceleration. Numerical simulations show that based on the beamline of the FACET-II, we can generate high-intensity two electron bunches with time delay from ∼ 100 fs to picoseconds, which will benefit the control of high-gradient witness bunch acceleration in a plasma.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW017

Export •

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

THPPA01

Demonstration of the Hollow Channel Plasma Wakefield Accelerator

3202

SUPSS117

use link to see paper's listing under its alternate paper code

S.J. Gessner, J.M. Allen, C.I. Clarke, J.-P. Delahaye, J.T. Frederico, S.Z. Green, C. Hast, M.J. Hogan, N. Lipkowitz, M.D. Litos, B.D. O'Shea, D.R. Walz, V. Yakimenko, G. Yocky
SLAC, Menlo Park, California, USA
E. Adli, C.A. Lindstrøm
University of Oslo, Oslo, Norway
W. An, C.E. Clayton, C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA
S. Corde, A. Doche
LOA, Palaiseau, France
W. Lu
TUB, Beijing, People's Republic of China

Funding: Work supported by DOE contract DE-AC02-76SF00515.
Over the past decade, there has been enormous progress in the field of beam and laser-driven plasma acceleration of electron beams. However, in order for plasma wakefield acceleration to be useful for a high-energy e⁺e^- collider, we need a technique for accelerating positrons in plasma as well. This is a unique challenge, because the plasma responds differently to electron and positron beams, with plasma electrons being pulled through the positron beam and creating a non-linear focusing force. Here, we demonstrate a technique called hollow channel acceleration that symmetrizes the wakefield response to beams of either charge. Using a transversely shaped laser pulse, we create an annular plasma with a fixed radius of 200 μm. We observe the acceleration of a positron bunch with energies up to 33.4 MeV in a 25 cm long channel, indicating an effective gradient greater than 100 MeV/m. This is the first demonstration of a technique that way be used for staged acceleration of positron beams in plasma.

Slides THPPA01 [5.647 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPPA01

Export •

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