| Paper |
Title |
Page |
| MOPPH051 |
Beam Stability Studies in the LCLS Linac
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94 |
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- J. L. Turner, R. Akre, A. Brachmann, F.-J. Decker, Y. T. Ding, D. Dowell, P. Emma, J. C. Frisch, A. Gilevich, G. R. Hays, P. Hering, Z. Huang, R. H. Iverson, C. Limborg-Deprey, H. Loos, A. Miahnahri, S. Molloy, H.-D. Nuhn, J. J. Welch, W. E. White, J. Wu
SLAC, Menlo Park, California
- D. F. Ratner
Stanford University, Stanford, Califormia
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The beam stability specifications for the Linac Coherent Light Source (LCLS) Free-Electron Laser (FEL) at Stanford Linear Accelerator Center (SLAC) are critical for X-Ray power, pointing, and timing stability. Studies of the transverse, longitudinal, and intensity stability of the electron beam are presented. Some sources are identified, correlated, and quantified.
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| MOPPH052 |
Commissioning Experience with the Linac Coherent Light Source Feedback Systems
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98 |
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- J. Wu, R. Akre, A. Brachmann, F.-J. Decker, Y. T. Ding, D. Dowell, P. Emma, D. Fairley, J. C. Frisch, A. Gilevich, G. R. Hays, P. Hering, Z. Huang, R. H. Iverson, C. Limborg-Deprey, H. Loos, A. Miahnahri, S. Molloy, H.-D. Nuhn, J. L. Turner, J. J. Welch, W. E. White
SLAC, Menlo Park, California
- D. F. Ratner
Stanford University, Stanford, Califormia
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The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) project under construction at SLAC. The machine commissioning includes the injector, the first and second bunch compressor stages, the linac up to 14 GeV, and the various beam diagnostics. To ensure the vitality of FEL lasing, it is critical to generate and preserve the high quality of the electron beam during acceleration and compression. The final beam quality can be very sensitive to system jitter. To minimize jitter, various transverse and longitudinal feedback systems are required. Here, we report the commissioning experience with these systems during the two phases of commissioning in 2007 - 2008.
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| TUPPH027 |
Measurements of Coherent Synchrotron Radiation and its Impact on the LCLS Electron Beam
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298 |
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- Z. Huang, K. L.F. Bane, F.-J. Decker, Y. T. Ding, D. Dowell, P. Emma, J. C. Frisch, R. H. Iverson, C. Limborg-Deprey, H. Loos, H.-D. Nuhn, G. V. Stupakov, J. L. Turner, J. J. Welch, J. Wu
SLAC, Menlo Park, California
- D. F. Ratner
Stanford University, Stanford, Califormia
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The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) project presently under construction at SLAC. Two separate magnetic dipole chicanes are used in the SLAC linac to compress the electron bunch length in stages, in order to reach the high peak current required for an x-ray FEL. In the bunch compressors, coherent synchrotron radiation (CSR) can be emitted–induced either by a short electron bunch, or by any longitudinal density modulation that may be on the bunch. We present measurements, simulations, and analysis of- the CSR-induced energy loss,
- the related transverse emittance growth, and
- the microbunching-induced CSR directly observed at optical wavelengths.
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| TUPPH033 |
LCLS Compressor Dipole Field Quality and Beam Measurements
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313 |
| |
- J. J. Welch, S. DeBarger, P. Emma, N. Li, J. Wu
SLAC, Menlo Park, California
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FELs typically use special arrangements of dipole magnets called chicanes to create an energy dependent path length needed for bunch compression. Ideally a chicane takes a beam with a linear correlation of energy and longitudinal position, and forms a compressed bunch with the same energy spread. To a very high degree the chicane should not generate residual dispersion which can convert energy spread into emittance and degrade the FEL. Linear dispersion is correctable but it is impractical to correct non-linear dispersion or non-linear focussing effects. Thus there are stringent demands on dipole field quality. The first LCLS chicane was initially found to generate substantial emittance growth. We made beam-based measurements of the net integrated magnetic field and determined that the dipole field quality was not adequate. Subsequently we modified two of the four dipoles to improve their good-field region. When reinstalled we found the chicane generated very little emittance growth. Beam-based measurement of the integrated field confirmed the improved dipole field quality.
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| THBAU01 |
Observation of Coherent Optical Transition Radiation in the LCLS Linac
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485 |
| |
- H. Loos, R. Akre, A. Brachmann, F.-J. Decker, Y. T. Ding, D. Dowell, P. Emma, J. C. Frisch, A. Gilevich, G. R. Hays, P. Hering, Z. Huang, R. H. Iverson, C. Limborg-Deprey, A. Miahnahri, S. Molloy, H.-D. Nuhn, J. L. Turner, J. J. Welch, W. E. White, J. Wu
SLAC, Menlo Park, California
- D. F. Ratner
Stanford University, Stanford, Califormia
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The beam diagnostics in the linac for the Linac Coherent Light Source (LCLS) X-ray FEL project at SLAC includes optical transition radiation (OTR) screens for measurements of transverse and longitudinal beam properties. We report on observations of coherent light emission from the OTR screens (COTR) at visible, near-IR and UV wavelengths from the uncompressed and compressed electron beam at various stages in the accelerator.
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Slides
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| FRAAU04 |
Commissioning of the LCLS Linac and Bunch Compressors
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548 |
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- P. Emma, R. Akre, A. Brachmann, F.-J. Decker, Y. T. Ding, D. Dowell, J. C. Frisch, A. Gilevich, G. R. Hays, P. Hering, Z. Huang, R. H. Iverson, C. Limborg-Deprey, H. Loos, A. Miahnahri, S. Molloy, H.-D. Nuhn, J. L. Turner, J. J. Welch, W. E. White, J. Wu
SLAC, Menlo Park, California
- D. F. Ratner
Stanford University, Stanford, Califormia
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The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) project under construction at SLAC*. The injector section, from drive-laser and RF photocathode gun through the first bunch compressor chicane, was commissioned in the spring and summer of 2007. The second phase of commissioning, including the second bunch compressor chicane and various main linac modifications, was completed in January through August of 2008. We report here on experience gained during this second phase of machine commissioning, including the injector, the first and second bunch compressor stages, the linac up to 14 GeV, and the various beam diagnostics and measurements. The final commissioning phase, including the undulator and the long transport line from the linac, is set to begin in December 2008, with first light in July 2009.
* J. Arthur et al. SLAC-R-593, April 2002.
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