2011 Particle Accelerator Conference - List of Authors (Walz, D.R.)

Paper

Title

Page

Status and Upgrades of the NLCTA for Studies of Advanced Beam Acceleration, Dynamics, and Manipulation

130

M.P. Dunning, C. Adolphsen, T.S. Chu, E.R. Colby, A. Gilevich, C. Hast, R.K. Jobe, C. Limborg-Deprey, D.J. McCormick, B.D. McKee, J. Nelson, T.O. Raubenheimer, K. Soong, G.V. Stupakov, Z.M. Szalata, D.R. Walz, F. Wang, S.P. Weathersby, M. Woodley, D. Xiang
SLAC, Menlo Park, California, USA

The Next Linear Collider Test Accelerator (NLCTA) is a low-energy electron accelerator (120 MeV) at SLAC that is used for ultra-high gradient X-band RF structure testing and advanced accelerator research. Here we give an overview of the current program at the facility, including the E-163 direct laser acceleration experiment, the echo-enabled harmonic generation (EEHG) FEL experiment, narrow-band THz generation, coherent optical transition radiation (COTR) studies, microbunching instability studies, and X-band structure testing. We also present the upgrades that are currently underway and some future programs utilizing these upgrades, including extension of the EEHG experiments to higher harmonics, and an emittance exchange experiment.

MOP015

An X-band Gun Test Area at SLAC

133

C. Limborg-Deprey, C. Adolphsen, T.S. Chu, M.P. Dunning, C. Hast, R.K. Jobe, E.N. Jongewaard, A.E. Vlieks, D.R. Walz, F. Wang
SLAC, Menlo Park, California, USA
S.G. Anderson, F.V. Hartemann, T.L. Houck, R.A. Marsh
LLNL, Livermore, California, USA

Funding: Work supported by the U.S. DOE Contract No. DE-AC03-76SF00515
The XTA (X-Band Test Area) is being assembled in the NLCTA tunnel of the SLAC National Laboratory to serve as a test facility for new RF guns. The first gun to be tested will be an upgraded version of the 5.6 cell, 200MV/m peak field X-band designed at SLAC in 2003 for the Compton Scattering experiment run in ASTA. This new version includes some features implemented in 2006 on the LCLS gun such as racetrack couplers, increased mode separation and elliptical irises. These upgrades were discussed in collaboration with LLNL since the same gun will be used as a driver for the LLNL Gamma-ray Source. Our beamline includes an X-band accelerating section which takes the electron beam up to 100 MeV and an electron beam measurement station. Other X-Band guns such as the UCLA Hybrid gun will be characterized at our facility.

TUP293

ESTB: A New Beam Test Facility at SLAC

1373

M.T.F. Pivi, H. Fieguth, C. Hast, R.H. Iverson, J. Jaros, R.K. Jobe, L. Keller, D.R. Walz, S.P. Weathersby, M. Woods
SLAC, Menlo Park, California, USA

End Station Test Beam (ESTB) is an end beam line at SLAC using a small fraction of the 13.6 GeV electron beam from the Linac Coherent Light Source (LCLS), restoring test beam capabilities in the large End Station A (ESA) experimental hall. In the past, 18 institutions participated in the ESA program at SLAC. The ESTB program will provide one of a kind test beams essential for developing accelerator instrumentation and accelerator R&D, performing particle and astroparticle physics detector research, linear collider machine and detector interface (MDI) R&D, developing of radiation-hard detectors and material damage studies with several distinctive features. At this stage, 4 new kicker magnets are added to divert 5 Hz of LCLS beam to the A-line, a new beam dump is installed and a new PPS system is built in ESA. In a second stage, a secondary hadron target will be installed, able to produce pions up to about 12 GeV/c at 1 particle/pulse. In summary, ESTB provides a new test facility for LHC detector upgrades, Super B Factory detector development, and Linear Collider accelerator and detector R&D with the first beam expected by June and users starting operations by July 2011.

TUOBN4

Plasma Wakefield Experiments at FACET

715

M.J. Hogan, R.J. England, J.T. Frederico, C. Hast, S.Z. Li, M.D. Litos, D.R. Walz
SLAC, Menlo Park, California, USA
W. An, C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, W.B. Mori, S. Tochitsky
UCLA, Los Angeles, California, USA
P. Muggli, S.F. Pinkerton, Y. Shi
USC, Los Angeles, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to ~20μm long and focused to ~10μm wide. The intense fields of the FACET bunches will be used to field ionize neutral lithium or cesium vapor produced in a heat pipe oven. Previous experiments at SLAC demonstrated 50GeV/m gradients in an 85cm field ionized lithium plasma where the interaction distance was limited by head erosion. Simulations indicate the lower ionization potential of cesium will decrease the rate of head erosion and increase single stage performance. The initial experimental program will compare the performance of lithium and cesium plasma sources with single and double bunches. Later experiments will investigate improved performance with a pre-ionized cesium plasma. The status of the experiments and expected performance are reviewed.

Slides TUOBN4 [13.080 MB]

TUODS3

Experimental Demonstration of the Echo-enabled Harmonic Generation Technique for Seeded FELs

D. Xiang, E.R. Colby, M.P. Dunning, A. Gilevich, C. Hast, R.K. Jobe, D.J. McCormick, J. Nelson, T.O. Raubenheimer, K. Soong, G.V. Stupakov, Z.M. Szalata, D.R. Walz, S.P. Weathersby, M. Woodley
SLAC, Menlo Park, California, USA

Funding: This work was supported by the US DOE under Contract No. DE-AC02-76SF00515.
Recently the scheme of echo-enabled harmonic generation (EEHG*) was proposed for short wavelength seeded FELs. This scheme allows far higher harmonic numbers to be accessed and makes the generation of coherent soft x-ray directly from a UV seed laser in a single stage possible**. In this paper we present the experimental demonstration*** of this echo harmonic technique at the Next Linear Collider Test Accelerator (NLCTA) at SLAC, where the coherent radiation at the harmonic frequency of the seed laser is generated using the 120 MeV electron beam. The experiment confirms the physics behind this technique and paves the way for applying it for seeded x-ray FELs.
* G. Stupakov, Phys. Rev. Lett, ZeHn2, 074801 (2009).
** D. Xiang and G. Stupakov, Phys. Rev. ST Accel. Beams 12, 030702 (2009).
*** D. Xiang, at al, Phys. Rev. Lett, ZeHn5, 114801 (2010).

Slides TUODS3 [3.936 MB]

THOBN4

Experiment to Demonstrate Acceleration in Optical Photonic Bandgap Structures

2067

R.J. England, E.R. Colby, R. Laouar, C. McGuinness, D. Mendez, C.-K. Ng, J.S.T. Ng, R.J. Noble, K. Soong, J.E. Spencer, D.R. Walz, Z. Wu, D. Xu
SLAC, Menlo Park, California, USA
E.A. Peralta
Stanford University, Stanford, California, USA

Funding: This work was funded by Department of Energy Grants DE-AC02-76SF00515, DE-FG06-97ER41276.
Optical scale dielectric structures offer a promising medium for high-gradient, compact, low-cost acceleration of charged particles. An experimental program is underway at the SLAC E163 facility to demonstrate acceleration in photonic bandgap structures driven by short laser pulses. We present initial experimental results, discuss structure and experimental design, and present first estimates of achievable gradient.

Slides THOBN4 [5.925 MB]

THP183

Measurement of Femtosecond LCLS Bunches Using the SLAC A-line Spectrometer*

2459

Z. Huang, A. Baker, M. Boyes, J. Craft, F.-J. Decker, Y.T. Ding, P. Emma, J.C. Frisch, R.H. Iverson, J.J. Lipari, H. Loos, D.R. Walz
SLAC, Menlo Park, California, USA
C. Behrens
DESY, Hamburg, Germany

We describe a novel technique and the preliminary experimental results to measure the ultrashort bunch length produced by the LCLS low-charge, highly compressed electron bunch. The technique involves adjusting the LCLS second bunch compressor followed by running the bunch on an rf zero-crossing phase of the final 550-m of linac. As a result, the time coordinate of the bunch is directly mapped onto the energy coordinate at the end of the linac. A high-resolution energy spectrometer located at an existing transport line (A-line) is then commissioned to image the energy profile of the bunch in order to retrieve its temporal information. We present measurements of the single-digit femtosecond LCLS bunch length using the A-line as a spectrometer and compare the results with the transverse cavity measurement as well as numerical simulations.

Paper	Title	Page
MOP014	Status and Upgrades of the NLCTA for Studies of Advanced Beam Acceleration, Dynamics, and Manipulation	130
	M.P. Dunning, C. Adolphsen, T.S. Chu, E.R. Colby, A. Gilevich, C. Hast, R.K. Jobe, C. Limborg-Deprey, D.J. McCormick, B.D. McKee, J. Nelson, T.O. Raubenheimer, K. Soong, G.V. Stupakov, Z.M. Szalata, D.R. Walz, F. Wang, S.P. Weathersby, M. Woodley, D. Xiang SLAC, Menlo Park, California, USA
	The Next Linear Collider Test Accelerator (NLCTA) is a low-energy electron accelerator (120 MeV) at SLAC that is used for ultra-high gradient X-band RF structure testing and advanced accelerator research. Here we give an overview of the current program at the facility, including the E-163 direct laser acceleration experiment, the echo-enabled harmonic generation (EEHG) FEL experiment, narrow-band THz generation, coherent optical transition radiation (COTR) studies, microbunching instability studies, and X-band structure testing. We also present the upgrades that are currently underway and some future programs utilizing these upgrades, including extension of the EEHG experiments to higher harmonics, and an emittance exchange experiment.

MOP015	An X-band Gun Test Area at SLAC	133
	C. Limborg-Deprey, C. Adolphsen, T.S. Chu, M.P. Dunning, C. Hast, R.K. Jobe, E.N. Jongewaard, A.E. Vlieks, D.R. Walz, F. Wang SLAC, Menlo Park, California, USA S.G. Anderson, F.V. Hartemann, T.L. Houck, R.A. Marsh LLNL, Livermore, California, USA
	Funding: Work supported by the U.S. DOE Contract No. DE-AC03-76SF00515 The XTA (X-Band Test Area) is being assembled in the NLCTA tunnel of the SLAC National Laboratory to serve as a test facility for new RF guns. The first gun to be tested will be an upgraded version of the 5.6 cell, 200MV/m peak field X-band designed at SLAC in 2003 for the Compton Scattering experiment run in ASTA. This new version includes some features implemented in 2006 on the LCLS gun such as racetrack couplers, increased mode separation and elliptical irises. These upgrades were discussed in collaboration with LLNL since the same gun will be used as a driver for the LLNL Gamma-ray Source. Our beamline includes an X-band accelerating section which takes the electron beam up to 100 MeV and an electron beam measurement station. Other X-Band guns such as the UCLA Hybrid gun will be characterized at our facility.

TUP293	ESTB: A New Beam Test Facility at SLAC	1373
	M.T.F. Pivi, H. Fieguth, C. Hast, R.H. Iverson, J. Jaros, R.K. Jobe, L. Keller, D.R. Walz, S.P. Weathersby, M. Woods SLAC, Menlo Park, California, USA
	End Station Test Beam (ESTB) is an end beam line at SLAC using a small fraction of the 13.6 GeV electron beam from the Linac Coherent Light Source (LCLS), restoring test beam capabilities in the large End Station A (ESA) experimental hall. In the past, 18 institutions participated in the ESA program at SLAC. The ESTB program will provide one of a kind test beams essential for developing accelerator instrumentation and accelerator R&D, performing particle and astroparticle physics detector research, linear collider machine and detector interface (MDI) R&D, developing of radiation-hard detectors and material damage studies with several distinctive features. At this stage, 4 new kicker magnets are added to divert 5 Hz of LCLS beam to the A-line, a new beam dump is installed and a new PPS system is built in ESA. In a second stage, a secondary hadron target will be installed, able to produce pions up to about 12 GeV/c at 1 particle/pulse. In summary, ESTB provides a new test facility for LHC detector upgrades, Super B Factory detector development, and Linear Collider accelerator and detector R&D with the first beam expected by June and users starting operations by July 2011.

TUOBN4	Plasma Wakefield Experiments at FACET	715
	M.J. Hogan, R.J. England, J.T. Frederico, C. Hast, S.Z. Li, M.D. Litos, D.R. Walz SLAC, Menlo Park, California, USA W. An, C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, W.B. Mori, S. Tochitsky UCLA, Los Angeles, California, USA P. Muggli, S.F. Pinkerton, Y. Shi USC, Los Angeles, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to ~20μm long and focused to ~10μm wide. The intense fields of the FACET bunches will be used to field ionize neutral lithium or cesium vapor produced in a heat pipe oven. Previous experiments at SLAC demonstrated 50GeV/m gradients in an 85cm field ionized lithium plasma where the interaction distance was limited by head erosion. Simulations indicate the lower ionization potential of cesium will decrease the rate of head erosion and increase single stage performance. The initial experimental program will compare the performance of lithium and cesium plasma sources with single and double bunches. Later experiments will investigate improved performance with a pre-ionized cesium plasma. The status of the experiments and expected performance are reviewed.
	Slides TUOBN4 [13.080 MB]

TUODS3	Experimental Demonstration of the Echo-enabled Harmonic Generation Technique for Seeded FELs
	D. Xiang, E.R. Colby, M.P. Dunning, A. Gilevich, C. Hast, R.K. Jobe, D.J. McCormick, J. Nelson, T.O. Raubenheimer, K. Soong, G.V. Stupakov, Z.M. Szalata, D.R. Walz, S.P. Weathersby, M. Woodley SLAC, Menlo Park, California, USA
	Funding: This work was supported by the US DOE under Contract No. DE-AC02-76SF00515. Recently the scheme of echo-enabled harmonic generation (EEHG) was proposed for short wavelength seeded FELs. This scheme allows far higher harmonic numbers to be accessed and makes the generation of coherent soft x-ray directly from a UV seed laser in a single stage possible. In this paper we present the experimental demonstration** of this echo harmonic technique at the Next Linear Collider Test Accelerator (NLCTA) at SLAC, where the coherent radiation at the harmonic frequency of the seed laser is generated using the 120 MeV electron beam. The experiment confirms the physics behind this technique and paves the way for applying it for seeded x-ray FELs. * G. Stupakov, Phys. Rev. Lett, ZeHn2, 074801 (2009). D. Xiang and G. Stupakov, Phys. Rev. ST Accel. Beams 12, 030702 (2009). * D. Xiang, at al, Phys. Rev. Lett, ZeHn5, 114801 (2010).
	Slides TUODS3 [3.936 MB]

THOBN4	Experiment to Demonstrate Acceleration in Optical Photonic Bandgap Structures	2067
	R.J. England, E.R. Colby, R. Laouar, C. McGuinness, D. Mendez, C.-K. Ng, J.S.T. Ng, R.J. Noble, K. Soong, J.E. Spencer, D.R. Walz, Z. Wu, D. Xu SLAC, Menlo Park, California, USA E.A. Peralta Stanford University, Stanford, California, USA
	Funding: This work was funded by Department of Energy Grants DE-AC02-76SF00515, DE-FG06-97ER41276. Optical scale dielectric structures offer a promising medium for high-gradient, compact, low-cost acceleration of charged particles. An experimental program is underway at the SLAC E163 facility to demonstrate acceleration in photonic bandgap structures driven by short laser pulses. We present initial experimental results, discuss structure and experimental design, and present first estimates of achievable gradient.
	Slides THOBN4 [5.925 MB]

THP183	Measurement of Femtosecond LCLS Bunches Using the SLAC A-line Spectrometer*	2459
	Z. Huang, A. Baker, M. Boyes, J. Craft, F.-J. Decker, Y.T. Ding, P. Emma, J.C. Frisch, R.H. Iverson, J.J. Lipari, H. Loos, D.R. Walz SLAC, Menlo Park, California, USA C. Behrens DESY, Hamburg, Germany
	We describe a novel technique and the preliminary experimental results to measure the ultrashort bunch length produced by the LCLS low-charge, highly compressed electron bunch. The technique involves adjusting the LCLS second bunch compressor followed by running the bunch on an rf zero-crossing phase of the final 550-m of linac. As a result, the time coordinate of the bunch is directly mapped onto the energy coordinate at the end of the linac. A high-resolution energy spectrometer located at an existing transport line (A-line) is then commissioned to image the energy profile of the bunch in order to retrieve its temporal information. We present measurements of the single-digit femtosecond LCLS bunch length using the A-line as a spectrometer and compare the results with the transverse cavity measurement as well as numerical simulations.