FEL2014 - List of Keywords (acceleration)

Paper	Title	Other Keywords	Page
THP063	Production of C-band Disk-loaded type CG Accelerating Structures	vacuum, operation, cavity, resonance	885
	N. Shigeoka, S. Miura, D. Suzuki MHI, Hiroshima, Japan T. Asaka, T. Inagaki, Y. Otake, T. Sakurai RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan H. Ego JASRI/SPring-8, Hyogo-ken, Japan
	In April 2013, MITSUBISHI HEAVY INDUSTRIES, LTD. contracted with RIKEN to produce six C-band disk-loaded type and constant gradient (CG) accelerating structures for removal of SCSS. These structures were newly designed by RIKEN for operation with an acceleration gradient of over 45 MeV/m and a repletion rate of 120 pps. The first structure was delivered in August 2013 to RIKEN and the other five was also delivered in March 2014. The accelerating structures were stacked from one hundred accelerating cells and formed by the vacuum brazing method. These cells using oxygen free copper were ultra-precisely machined. Unlike the C-band choke-mode type structures, which MHI manufactured in past for SACLA, the accelerating cells of the CG structure can be tuned after the brazing by pushing dimpling at the tuning hole of each cell. Demands of a VSWR < 1.1 and a phase error < 3 degree are fulfilled after the tuning by using the nodal shift method, which corrects cell frequency shifts due to the machining errors of cells and a cell’s deformation by the heat cycle of the brazing. The detailed results of the production and low-power RF tests will be presented in this presentation.
	Poster THP063 [0.623 MB]

FRB02	A Collinear Wakefield Accelerator for a High Repetition Rate Multi-beamline Soft X-ray FEL Facility	wakefield, electron, FEL, emittance	993
	A. Zholents, W. Gai, R.R. Lindberg, J.G. Power, Y.-E. Sun ANL, Argonne, Ilinois, USA C.-J. Jing, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA C. Li, C.-X. Tang TUB, Beijing, People's Republic of China D.Y. Shchegolkov, E.I. Simakov LANL, Los Alamos, New Mexico, USA
	Funding: Supported by U.S. Department of Energy under Contract No. DE-AC02-06CH11357 and by the U.S. Department of Energy Laboratory LDRD program at Los Alamos National Laboratory. A concept is presented for a multi beamline soft x-ray free-electron laser (FEL) facility where several FEL undulator lines are driven by an equal number of high repetition rate single-stage collinear wakefield accelerators (CWA). A practical design of the CWA, extending over 30 meters and embedded into a quadrupole wiggler, is considered. The wiggler’s structure of alternating focusing and defocusing quadrupoles is used to control single-bunch breakup instability. It is shown that practical restrictions on the maximum attainable quadrupole field limit the maximum attainable charge in the drive bunch whose sole purpose is to produce a high accelerating field in the CWA for the following main bunch. It is also pointed out that the distance between drive and main bunches varies along the accelerator, causing a measurable impact on the energy gain by the main bunch and on the energy spread of electrons in it. Means to mitigate these effects are proposed and results are presented for numerical simulations demonstrating the main bunch with plausible parameters for FEL application including a relatively small energy spread. Finally, results are presented for the expected FEL performance using an appropriately chosen undulator.
	Slides FRB02 [6.512 MB]

FRB04	Divergence Reduction and Emittance Conservation in a Laser Plasma Acceleration Stage	plasma, laser, emittance, extraction	999
	A.R. Maier, I. Dornmair CFEL, Hamburg, Germany K. Flöttmann DESY, Hamburg, Germany
	Plasma accelerators promise a compact source of highly relativistic electron beams. Driven by high-intensity lasers or high-energetic electron beams, the longitudinal and transverse electric fields inside the plasma cavitiy support the generation of GeV electron beams over m-scale distances, while measured emittances on the order of 0.1 mm.mrad have been reported from plasma-driven accelerators. However, it remains challenging to conserve this excellent emittance when coupling from the plasma into vacuum and a subsequent beam optics, especially when considering the large energy spread, typically accumulated during the off-crest acceleration inside the plasma. Recently, we presented an analytical solution [1] to describe an adiabatic matching from the plasma into vacuum. Further elaborating this concept [2], we will discuss the generation of low-divergence electron beams from a tailored plasma target in order to preserve the emittance generated within the plasma. We will apply our concept to an externally injected electron bunch, that is matched in and out of a tailored plasma target, generating a GeV-level electron beam with low divergence and good emittance. * K. Floettmann, Phys. Rev. ST - Accel. Beams 17, 054402 (2014) ** I. Dornmair, K. Floettmann, and A. R. Maier, submitted (2014)

Paper

Title

Other Keywords

Page

THP063

Production of C-band Disk-loaded type CG Accelerating Structures

vacuum, operation, cavity, resonance

885

N. Shigeoka, S. Miura, D. Suzuki
MHI, Hiroshima, Japan
T. Asaka, T. Inagaki, Y. Otake, T. Sakurai
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
H. Ego
JASRI/SPring-8, Hyogo-ken, Japan

In April 2013, MITSUBISHI HEAVY INDUSTRIES, LTD. contracted with RIKEN to produce six C-band disk-loaded type and constant gradient (CG) accelerating structures for removal of SCSS. These structures were newly designed by RIKEN for operation with an acceleration gradient of over 45 MeV/m and a repletion rate of 120 pps. The first structure was delivered in August 2013 to RIKEN and the other five was also delivered in March 2014. The accelerating structures were stacked from one hundred accelerating cells and formed by the vacuum brazing method. These cells using oxygen free copper were ultra-precisely machined. Unlike the C-band choke-mode type structures, which MHI manufactured in past for SACLA, the accelerating cells of the CG structure can be tuned after the brazing by pushing dimpling at the tuning hole of each cell. Demands of a VSWR < 1.1 and a phase error < 3 degree are fulfilled after the tuning by using the nodal shift method, which corrects cell frequency shifts due to the machining errors of cells and a cell’s deformation by the heat cycle of the brazing. The detailed results of the production and low-power RF tests will be presented in this presentation.

Poster THP063 [0.623 MB]

FRB02

A Collinear Wakefield Accelerator for a High Repetition Rate Multi-beamline Soft X-ray FEL Facility

wakefield, electron, FEL, emittance

993

A. Zholents, W. Gai, R.R. Lindberg, J.G. Power, Y.-E. Sun
ANL, Argonne, Ilinois, USA
C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
C. Li, C.-X. Tang
TUB, Beijing, People's Republic of China
D.Y. Shchegolkov, E.I. Simakov
LANL, Los Alamos, New Mexico, USA

Funding: Supported by U.S. Department of Energy under Contract No. DE-AC02-06CH11357 and by the U.S. Department of Energy Laboratory LDRD program at Los Alamos National Laboratory.
A concept is presented for a multi beamline soft x-ray free-electron laser (FEL) facility where several FEL undulator lines are driven by an equal number of high repetition rate single-stage collinear wakefield accelerators (CWA). A practical design of the CWA, extending over 30 meters and embedded into a quadrupole wiggler, is considered. The wiggler’s structure of alternating focusing and defocusing quadrupoles is used to control single-bunch breakup instability. It is shown that practical restrictions on the maximum attainable quadrupole field limit the maximum attainable charge in the drive bunch whose sole purpose is to produce a high accelerating field in the CWA for the following main bunch. It is also pointed out that the distance between drive and main bunches varies along the accelerator, causing a measurable impact on the energy gain by the main bunch and on the energy spread of electrons in it. Means to mitigate these effects are proposed and results are presented for numerical simulations demonstrating the main bunch with plausible parameters for FEL application including a relatively small energy spread. Finally, results are presented for the expected FEL performance using an appropriately chosen undulator.

Slides FRB02 [6.512 MB]

FRB04

Divergence Reduction and Emittance Conservation in a Laser Plasma Acceleration Stage

plasma, laser, emittance, extraction

999

A.R. Maier, I. Dornmair
CFEL, Hamburg, Germany
K. Flöttmann
DESY, Hamburg, Germany

Plasma accelerators promise a compact source of highly relativistic electron beams. Driven by high-intensity lasers or high-energetic electron beams, the longitudinal and transverse electric fields inside the plasma cavitiy support the generation of GeV electron beams over m-scale distances, while measured emittances on the order of 0.1 mm.mrad have been reported from plasma-driven accelerators. However, it remains challenging to conserve this excellent emittance when coupling from the plasma into vacuum and a subsequent beam optics, especially when considering the large energy spread, typically accumulated during the off-crest acceleration inside the plasma. Recently, we presented an analytical solution [1] to describe an adiabatic matching from the plasma into vacuum. Further elaborating this concept [2], we will discuss the generation of low-divergence electron beams from a tailored plasma target in order to preserve the emittance generated within the plasma. We will apply our concept to an externally injected electron bunch, that is matched in and out of a tailored plasma target, generating a GeV-level electron beam with low divergence and good emittance.
* K. Floettmann, Phys. Rev. ST - Accel. Beams 17, 054402 (2014)
** I. Dornmair, K. Floettmann, and A. R. Maier, submitted (2014)