IPAC2013 - List of Authors (Woodley, M.)

Paper	Title	Page
MOPWO023	Upgrade and Systematic Measurement Campaign of the ATF2 Multi-OTR System	933
	A. Faus-Golfe, J. Alabau-Gonzalvo, C. Blanch Gutierrez, J. Resta-López IFIC, Valencia, Spain J. Cruz, E. Marín, D.J. McCormick, G.R. White, M. Woodley SLAC, Menlo Park, California, USA
	A multi-Optical Transition Radiation (mOTR) system made of four stations is being used routinely since September 2011 for transverse beam size measurement and emittance reconstruction in the extraction line of ATF2, providing diagnostic support during the ATF2 tuning operation. Furthermore it is also an excellent tool for fast transverse coupling correction. Due to the compactness of the current design the system has an influence in the increase of the transverse emittance due to wakefield effects when a simultaneous measurement is made. To avoid this effect a new target holder and a new optics has been designed and implemented. In this paper we describe the present status of the ATF2 mOTR system, showing recent performance results, and hardware design improvements.

TUPEA085	Optics Tuning and Compensation in LCLS-II	1313
	Y. Nosochkov, T.O. Raubenheimer, M. Woodley SLAC, Menlo Park, California, USA
	Funding: Work supported by the US Department of Energy contract DE-AC02-76SF00515. The LCLS-II is a future upgrade of the Linear Coherent Light Source (LCLS) at SLAC. It will include two new Free Electron Lasers (FELs) to generate soft and hard X-ray radiation. The 2.9 km LCLS-II lattice will include 1/3 of the SLC linac located just before the existing LCLS, the 1.2 km bypass line, the bend section, the beam separation and diagnostic regions, and the FEL undulators and dump. The LCLS operation showed that occasionally the beam phase space may be significantly mismatched due to various errors in the beamline. This requires correction to ensure good beam quality in the undulators. Similarly, the LCLS-II must have lattice correction system with a large tuning range to cancel such errors. Since the various LCLS-II regions are connected using matching sections, the latter naturally can be used for correction of the mismatched lattice functions. In addition, the large tuning capability is required to provide a wide range of focusing conditions at the FEL undulators. The compensation and tuning abilities of the LCLS-II lattice have been studied for incoming beam errors equivalent to 160% of beta beat and for a factor of 5 in the range of undulator quadrupole strengths.

TUPWO065	Anomalously Long Bunches from the SLAC North Damping Ring	2015
	G. Yocky, F.-J. Decker, N. Lipkowitz, U. Wienands, M. Woodley SLAC, Menlo Park, California, USA
	The SLC damping ring provides emittance reduced beam to the beginning of the FACET accelerator. In measurements conducted during the 2012 FACET run, we find the bunch-length to be ~20% longer than canonical. A study is performed with longitudinal simulation code to determine the impact on the various stages of compression for FACET experimental running.

TUPWO067	Start-to-end Particle Tracking of the FACET Accelerator	2018
	N. Lipkowitz, F.-J. Decker, G.R. White, M. Woodley, G. Yocky SLAC, Menlo Park, California, USA
	Funding: Work supported by Department of Energy contract DE-AC02-76SF00515. The Facility for Advanced aCcelerator Experimental Tests (FACET) consists of the first two-thirds of the SLAC two-mile linac followed by a final focus and experimental end station. To date, wakefield-dominated emittance growth and dispersion in the linac, as well as dispersive and chromatic effects in the final focus have precluded regular reliable operation that meets the design parameters for final spot size. In this work, a 6-D particle tracking code (Lucretia) is used to simulate the complete machine, with input parameters taken directly from saved machine configurations. Sensitivities of various tuning parameters to the final spot sizes are compared with measurements taken from the real machine, and a set of tuning protocols is determined to improve regular machine operation.

TUPWO068	Performance Improvements of the SLAC Linac for the FACET Beam	2021
	F.-J. Decker, N. Lipkowitz, E. Marín, Y. Nosochkov, J. Sheppard, M.K. Sullivan, Y. Sun, M.-H. Wang, G.R. White, U. Wienands, M. Woodley, G. Yocky SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S.Department of Energy, Contract DE-AC02-76SF00515. Two thirds of the SLAC Linac is used to generate a short, intense electron beam for the FACET experiments. The emittance growth along the Linac is a major concern to finally get small spot sizes for these experiments. There are two different approaches to get the required small emittances: a) lengthy iterative global tuning technique, and b) trying to identify locations of the main sources of the emittance growth and reducing their effect locally. How these approaches help to get good beam performances is discussed.

TUPWO069	Optimization of FACET Optics	2024
	M.-H. Wang, F.-J. Decker, N. Lipkowitz, Y. Nosochkov, G.R. White, U. Wienands, M. Woodley, G. Yocky SLAC, Menlo Park, California, USA
	Funding: supported by the US Department of Energy contract DE-AC02-76SF00515. The FACET accelerator facility is designed to provide short and intense e^- or e⁺ bunches with small spot size for plasma wakefield accelerator research and other experiments. It is based on the SLAC linac with a compressor chicane in sector-10, and a second compressor chicane and final focus in sector-20 (S20). Originally, the S20 chicane was designed to be compatible with an upgrade to include a second S20 chicane for simultaneous transport of e^- and e⁺ bunches. This placed additional optics constraints which lead to strong focusing in the S20 chicane. The latter increases the effects of errors causing emittance growth. Lately, it has been decided not to proceed with the upgrade option. Therefore, there is a potential for improving the optics by relaxing the constraints. In this study, we explore alternative optics designs where beta functions in the S20 chicane and final focus are reduced in order to minimize the error effects. The optics and non-linear aberrations are evaluated, and the chromatic correction is optimized for each design. Beam tracking simulations are performed using Elegant and Lucretia. The most optimal designs are identified based on these simulations.

Paper

Title

Page

Upgrade and Systematic Measurement Campaign of the ATF2 Multi-OTR System

933

A. Faus-Golfe, J. Alabau-Gonzalvo, C. Blanch Gutierrez, J. Resta-López
IFIC, Valencia, Spain
J. Cruz, E. Marín, D.J. McCormick, G.R. White, M. Woodley
SLAC, Menlo Park, California, USA

A multi-Optical Transition Radiation (mOTR) system made of four stations is being used routinely since September 2011 for transverse beam size measurement and emittance reconstruction in the extraction line of ATF2, providing diagnostic support during the ATF2 tuning operation. Furthermore it is also an excellent tool for fast transverse coupling correction. Due to the compactness of the current design the system has an influence in the increase of the transverse emittance due to wakefield effects when a simultaneous measurement is made. To avoid this effect a new target holder and a new optics has been designed and implemented. In this paper we describe the present status of the ATF2 mOTR system, showing recent performance results, and hardware design improvements.

TUPEA085

Optics Tuning and Compensation in LCLS-II

1313

Y. Nosochkov, T.O. Raubenheimer, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Work supported by the US Department of Energy contract DE-AC02-76SF00515.
The LCLS-II is a future upgrade of the Linear Coherent Light Source (LCLS) at SLAC. It will include two new Free Electron Lasers (FELs) to generate soft and hard X-ray radiation. The 2.9 km LCLS-II lattice will include 1/3 of the SLC linac located just before the existing LCLS, the 1.2 km bypass line, the bend section, the beam separation and diagnostic regions, and the FEL undulators and dump. The LCLS operation showed that occasionally the beam phase space may be significantly mismatched due to various errors in the beamline. This requires correction to ensure good beam quality in the undulators. Similarly, the LCLS-II must have lattice correction system with a large tuning range to cancel such errors. Since the various LCLS-II regions are connected using matching sections, the latter naturally can be used for correction of the mismatched lattice functions. In addition, the large tuning capability is required to provide a wide range of focusing conditions at the FEL undulators. The compensation and tuning abilities of the LCLS-II lattice have been studied for incoming beam errors equivalent to 160% of beta beat and for a factor of 5 in the range of undulator quadrupole strengths.

TUPWO065

Anomalously Long Bunches from the SLAC North Damping Ring

2015

G. Yocky, F.-J. Decker, N. Lipkowitz, U. Wienands, M. Woodley
SLAC, Menlo Park, California, USA

The SLC damping ring provides emittance reduced beam to the beginning of the FACET accelerator. In measurements conducted during the 2012 FACET run, we find the bunch-length to be ~20% longer than canonical. A study is performed with longitudinal simulation code to determine the impact on the various stages of compression for FACET experimental running.

TUPWO067

Start-to-end Particle Tracking of the FACET Accelerator

2018

N. Lipkowitz, F.-J. Decker, G.R. White, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: Work supported by Department of Energy contract DE-AC02-76SF00515.
The Facility for Advanced aCcelerator Experimental Tests (FACET) consists of the first two-thirds of the SLAC two-mile linac followed by a final focus and experimental end station. To date, wakefield-dominated emittance growth and dispersion in the linac, as well as dispersive and chromatic effects in the final focus have precluded regular reliable operation that meets the design parameters for final spot size. In this work, a 6-D particle tracking code (Lucretia) is used to simulate the complete machine, with input parameters taken directly from saved machine configurations. Sensitivities of various tuning parameters to the final spot sizes are compared with measurements taken from the real machine, and a set of tuning protocols is determined to improve regular machine operation.

TUPWO068

Performance Improvements of the SLAC Linac for the FACET Beam

2021

F.-J. Decker, N. Lipkowitz, E. Marín, Y. Nosochkov, J. Sheppard, M.K. Sullivan, Y. Sun, M.-H. Wang, G.R. White, U. Wienands, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S.Department of Energy, Contract DE-AC02-76SF00515.
Two thirds of the SLAC Linac is used to generate a short, intense electron beam for the FACET experiments. The emittance growth along the Linac is a major concern to finally get small spot sizes for these experiments. There are two different approaches to get the required small emittances: a) lengthy iterative global tuning technique, and b) trying to identify locations of the main sources of the emittance growth and reducing their effect locally. How these approaches help to get good beam performances is discussed.

TUPWO069

Optimization of FACET Optics

2024

M.-H. Wang, F.-J. Decker, N. Lipkowitz, Y. Nosochkov, G.R. White, U. Wienands, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: supported by the US Department of Energy contract DE-AC02-76SF00515.
The FACET accelerator facility is designed to provide short and intense e^- or e⁺ bunches with small spot size for plasma wakefield accelerator research and other experiments. It is based on the SLAC linac with a compressor chicane in sector-10, and a second compressor chicane and final focus in sector-20 (S20). Originally, the S20 chicane was designed to be compatible with an upgrade to include a second S20 chicane for simultaneous transport of e^- and e⁺ bunches. This placed additional optics constraints which lead to strong focusing in the S20 chicane. The latter increases the effects of errors causing emittance growth. Lately, it has been decided not to proceed with the upgrade option. Therefore, there is a potential for improving the optics by relaxing the constraints. In this study, we explore alternative optics designs where beta functions in the S20 chicane and final focus are reduced in order to minimize the error effects. The optics and non-linear aberrations are evaluated, and the chromatic correction is optimized for each design. Beam tracking simulations are performed using Elegant and Lucretia. The most optimal designs are identified based on these simulations.