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Emma, P.

Paper Title Page
MOPAS057 Database Applications to Integrate Beamline Optics Changes into Engineering Databases 563
  • A. Chan, P. Bellomo, G. R. Crane, P. Emma, E. Grunhaus, K. Luchini, I. A. MacGregor, D. S. Marsh, R. Pope, P. L. Prickett, E. Rago, K. Ratcliffe, T. Shab
    SLAC, Menlo Park, California
  Funding: This work was performed in support of the LCLS project at SLAC and funded by Department of Energy contract DE-AC02-76SF00515

Changes to beamline optics may effect many engineering processes downstream. In the past, we incorporated these changes manually into disparate engineering spreadsheets. At LCLS, database applications have been developed in order to compare and clearly display differences amongst various versions of beamline optics files. These applications also incorporate the changes into engineering databases, after they have been validated by the engineers. This allows the engineers to be notified, and modifications to be made if beamline optics changes require corresponding adjustments of engineering elements. This paper will describe how this streamlines the workflow, and also provides greater reliability in how beamline optics changes are integrated into engineering databases (such as cabling, power supplies, inventory). The paper includes a description of the related LCLS inventory system, which also serves as a repository for quality assurance documents. The underlying database schemas and applications will be outlined.

TUOCAB02 Measurements of Compression and Emittance Growth after the First LCLS Bunch Compressor Chicane 807
  • P. Emma, K. L.F. Bane, Y. T. Ding, J. C. Frisch, Z. Huang, H. Loos, G. V. Stupakov, J. Wu
    SLAC, Menlo Park, California
  • E. Prat
    DESY, Hamburg
  • F. Sannibale, K. G. Sonnad, M. S. Zolotorev
    LBNL, Berkeley, California
  Funding: U. S. Depertment of Energy contract #DE-AC02-76SF00515.

The Linac Coherent Light Source (LCLS) is a SASE x-ray free-electron laser project presently under construction at SLAC. The injector section from RF photocathode gun through the first bunch compressor chicane was installed during the Fall of 2006. The first bunch compressor chicane is located at 250 MeV and nominally compresses a 1-nC electron bunch from an rms length of about 1 mm to 0.2 mm. The degree of compression is highly adjustable using RF phasing and also chicane magnetic field variations. Transverse phase space and bunch length diagnostics are located immediately after the chicane. We present measurements and simulations of the longitudinal and transverse phase space after the chicane in various beam conditions, including extreme compression where coherent radiation effects are expected to be striking.

slides icon Slides  
TUPMS046 Integration of the Optical Replica Ultrashort Electron Bunch Diagnostics with the Current-Enhanced SASE in the LCLS 1293
  • Y. T. Ding, P. Emma, Z. Huang
    SLAC, Menlo Park, California
  In this paper, we present a feasibility study of integrating the optical replica (OR) ultrashort electron bunch diagnostics * with the current-enhanced SASE (ESASE) scheme ** in the LCLS. Both techniques involve using an external laser to energy-modulate the electron beam in a short wiggler and converting the energy modulation to a density modulation in a dispersive section. While ESASE proposes to use the high-current spikes to enhance the FEL signal, the OR method extracts the optical coherent radiation produced by a density modulated electron beam for frequency resolved optical gating (FROG) diagnostics. We discuss the optimization studies of combining the OR method with the ESASE after the second bunch compressor in the LCLS. Simulation results show that the OR method is capable of reproducing the expected double-horn current profile of a 200-fs bunch. The possibilities and limitations of reconstructing the longitudinal phase space profile are also explored.

* E. Saldin et al, Nucl. Instr. and Meth. A 539, 499 (2005).** A. Zholents, Phys. Rev. ST Accel. Beams 8, 040701 (2005); A. Zholents et al., in Proceedings of FEL2004, 582 (2004).

TUPMS049 Initial Commissioning Experience with the LCLS Injector 1302
  • P. Emma, R. Akre, J. Castro, Y. T. Ding, D. Dowell, J. C. Frisch, A. Gilevich, G. R. Hays, P. Hering, Z. Huang, R. H. Iverson, P. Krejcik, C. Limborg-Deprey, H. Loos, A. Miahnahri, C. H. Rivetta, M. E. Saleski, J. F. Schmerge, D. C. Schultz, J. L. Turner, J. J. Welch, W. E. White, J. Wu
    SLAC, Menlo Park, California
  • L. Froehlich, T. Limberg, E. Prat
    DESY, Hamburg
  Funding: U. S. Department of Energy contract #DE-AC02-76SF00515.

The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) project presently under construction at SLAC. The injector section, from drive-laser and RF photocathode gun through the first bunch compressor chicane, was installed during the Fall of 2006. Initial system commissioning with an electron beam takes place in the Spring and Summer of 2007. The second phase of construction, including the second bunch compressor and the FEL undulator, will begin later, in the Fall of 2007. We report here on experience gained during the first phase of machine commissioning, including RF photocathode gun, linac booster section, energy spectrometers, S-band and X-band RF systems, the first bunch compressor stage, and the various beam diagnostics.

TUPMS058 The LCLS Injector Drive Laser 1317
  • W. E. White, J. Castro, P. Emma, A. Gilevich, C. Limborg-Deprey, H. Loos, A. Miahnahri
    SLAC, Menlo Park, California
  Requirements for the LCLS injector drive laser present significant challenges to the design of the system. While progress has been demonstrated in spatial shape, temporal shape, UV generation and rep-rate, a laser that meets all of the LCLS specifications simultaneously has yet to be demonstrated. These challenges are compounded by the stability and reliability requirements. The drive laser and transport system has been installed and tested. We will report on the current operational state of the laser and plans for future improvements.  
WEPMS036 LCLS LLRF Upgrades to the SLAC Linac 2421
  • R. Akre, D. Dowell, P. Emma, J. C. Frisch, B. Hong, K. D. Kotturi, P. Krejcik, J. Wu
    SLAC, Menlo Park, California
  • J. M. Byrd
    LBNL, Berkeley, California
  Funding: DOE

The Linac Coherent Light Source at SLAC will be the brightest X-ray laser in the world when it comes on line. In order to achieve the brightness a 100fS length electron bunch is passed through an undulator. To creat the 100fS bunch, a 10pS electron bunch, created from a photo cathode in an RF gun, is run off crest on the RF to set up a position to energy correlation. The bunch is then compressed chicanes. The stability of the RF system is critical in setting up the position to energy correlation. Specifications derived from simulations require the RF system to be stable to below 100fS in several critical injector stations and the last kilometer of linac. The SLAC linac RF system is being upgraded to meet these requirements.

TUPMN039 Status of the SPARC-X Project 1001
  • C. Vaccarezza, D. Alesini, M. Bellaveglia, S. Bertolucci, R. Boni, M. Boscolo, M. Castellano, A. Clozza, L. Cultrera, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, L. Ficcadenti, D. Filippetto, V. Fusco, A. Gallo, G. Gatti, A. Ghigo, C. Ligi, M. Migliorati, A. Mostacci, E. Pace, L. Palumbo, L. Pellegrino, M. A. Preger, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stella, F. Tazzioli, M. Vescovi, C. Vicario
    INFN/LNF, Frascati (Roma)
  • F. Alessandria, A. Bacci, R. Bonifacio, I. Boscolo, F. Broggi, F. Castelli, S. Cialdi, C. De Martinis, A. F. Flacco, D. Giove, C. Maroli, V. Petrillo, A. R. Rossi, L. Serafini
    INFN-Milano, Milano
  • M. Bougeard, P. Breger, B. Carre, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Monchicourt, P. Salieres, O. Tcherbakoff
    CEA, Gif-sur-Yvette
  • L. Catani, E. Chiadroni, A. Cianchi, E. Gabrielli, C. Schaerf
    INFN-Roma II, Roma
  • F. Ciocci, G. Dattoli, A. Dipace, A. Doria, F. Flora, G. P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, P. L. Ottaviani, S. Pagnutti, G. Parisi, L. Picardi, M. Quattromini, A. Renieri, G. Ronci, C. Ronsivalle, M. Rosetti, E. Sabia, M. Sassi, A. Torre, A. Zucchini
    ENEA C. R. Frascati, Frascati (Roma)
  • M.-E. Couprie
    SOLEIL, Gif-sur-Yvette
  • P. Emma
    SLAC, Menlo Park, California
  • M. Mattioli, D. Pelliccia
    Universita di Roma I La Sapienza, Roma
  • P. Musumeci, M. Petrarca
    INFN-Roma, Roma
  • C. Pellegrini, S. Reiche, J. B. Rosenzweig
    UCLA, Los Angeles, California
  • A. Perrone
    INFN-Lecce, Lecce
  SPARC-X is a two branch project consisting in the SPARC test facility dedicated to the development and test of critical subsystems such as high brightness photoinjector and a modular expandable undulator for SASE-FEL experiments at 500 nm with seeding, and the SPARX facility aiming at generation of high brightness coherent radiation in the 3-13 nm range, based on the achieved expertise. The projects are supported by MIUR (Research Department of Italian Government) and Regione Lazio. SPARC has completed the commissioning phase of the photoinjector in November 2006. The achieved experimental results are here summarized together with the status of the second phase commissioning plans. The SPARX project is based on the generation of ultrahigh peak brightness electron beams at the energy of 1 and 2 GeV generating radiation in the 3-13 nm range. The construction is at the moment planned in two steps starting with a 1 GeV Linac. The project layout including both RF-compression and magnetic chicane techniques has been studied and compared, together with the feasibility of a mixed s-band and x-band linac option.  
FRPMS071 Relative Bunch Length Monitor for the Linac Coherent Light Source (LCLS) using Coherent Edge Radiation 4189
  • H. Loos, T. Borden, P. Emma, J. C. Frisch, J. Wu
    SLAC, Menlo Park, California
  Funding: This work was supported by U. S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC03-76SF00515

The ultra-short bunches of the electron beam for LCLS are generated in two 4-dipole bunch compressors located at energies of 250 MeV and 4.3 GeV. Although an absolute measurement of the bunch length can be done by using a transverse deflecting cavity in an interceptive mode, a non-interceptive single shot method is needed as a relative measurement of the bunch length used in the continuous feedback for beam energy and peak current. We report on the design and implementation of two monitors measuring the integrated power of coherent edge radiation from the last dipole in each chicane. The first monitor is installed in early 2007 and we compare its performance with the transverse cavity measurement and other techniques.

FRPMS073 Picosecond Bunch Length and Energy-z Correlation Measurements at SLAC's A-Line and End Station A 4201
  • S. Molloy, P. Emma, J. C. Frisch, R. H. Iverson, D. J. McCormick, M. Woods
    SLAC, Menlo Park, California
  • V. Blackmore
    OXFORDphysics, Oxford, Oxon
  • M. C. Ross
    Fermilab, Batavia, Illinois
  • S. Walston
    LLNL, Livermore, California
  Funding: US DOE Contract #DE-AC02-76FS00515

We report on measurements of picosecond bunch lengths and the energy-z correlation of the bunch with a high energy electron test beam to the A-line and End Station A (ESA) facilities at SLAC. The bunch length and the energy-z correlation of the bunch are measured at the end of the linac using a synchrotron light monitor diagnostic at a high dispersion point in the A-line and a transverse RF deflecting cavity at the end of the linac. Measurements of the bunch length in ESA were made using high frequency diodes (up to 100 GHz) and pyroelectric detectors at a ceramic gap in the beamline. Modelling of the beam's longitudinal phase space through the linac and A-line to ESA is done using the 2-dimensional tracking program LiTrack, and LiTrack simulation results are compared with data. High frequency diode and pyroelectric detectors are planned to be used as part of a bunch length feedback system for the LCLS FEL at SLAC. The LCLS also plans precise bunch length and energy-z correlation measurements using transverse RF deflecting cavities.