PAC07 - List of Keywords (brightness)

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brightness

Paper	Title	Other Keywords	Page
MOPAS044	The Laser System for the ERL Electron Source at Cornell University	laser, electron, gun, polarization	530
	D. G. Ouzounov I. V. Bazarov, B. M. Dunham, C. K. Sinclair Cornell University, Department of Physics, Ithaca, New York F. W. Wise, S. Zhou Cornell University, Ithaca, New York
	Funding: Work Supported by the National Science Foundation under contract PHY 0131508 Cornell University is developing a high brightness, high average current electron source for the injector of an ERL based synchrotron radiation source. The source is a DC electron gun with a negative electron affinity photoemission cathode. The photocathode is illuminated by a 1300 MHz CW train of optical pulses to produce a 100 mA average current beam. The optical pulse train is generated by frequency doubling the output of a diode-pumped, mode-locked Yb-fiber oscillator-amplifier system. The 50 MHz fundamental frequency oscillator is locked on its 26th harmonic to produce the 1300 MHz train. The oscillator output is amplified in three stages and doubled to give 26 W in the green. The doubled beam is diffraction limited (M2 = 1.08) with a pulse width of 2.5 ps. This pulse is split and differentially delayed in a series of birefringent crystals to produce a flat top temporal profile with fast rise and fall times. The final pulse shape is measured by cross-correlation. The pulses are spatially shaped by a commercial aspheric lens system. A full power system operating at 50 MHz is in routine use for electron beam measurements. Detailed laser performance information will be presented.

TUPMN005	Optimizing Beam Brightness at the Canadian Light Source	emittance, coupling, undulator, dipole	920
	L. O. Dallin D. Bodnarchuk, T. Summers CLS, Saskatoon, Saskatchewan
	The Canadian Light Source (CLS) storage ring has been operating routinely since commissioning was completed in the spring of 2004. Since that time the storage ring parameters have been adjusted in efforts to increase the brightness of the source. This includes changes to the operating point, reducing the transverse coupling and optimizing the dispersion at the source points. Depending on the photon energy brightness from undulators is increased by reducing the beam size or reducing the emittance. This is achieved with higher tunes which both decrease the emittance and beta-functions. Dispersion at the undulators can be optimized to minimize the effective beam emittance or beam size. Vertical coupling can be adjusted to less than 0.1% by both reducing the vertical dispersion and transverse coupling from the horizontal motion.

TUPMN028	The New Photoinjector for the Fermi Project	gun, emittance, vacuum, cathode	974
	G. D'Auria D. Bacescu, L. Badano, F. Cianciosi, P. Craievich, M. B. Danailov, G. Penco, L. Rumiz, M. Trovo, A. Turchet ELETTRA, Basovizza, Trieste H. Badakov, A. Fukasawa, B. D. O'Shea, J. B. Rosenzweig UCLA, Los Angeles, California
	FERMI@ELETTRA is a single-pass FEL user facility covering the spectral range 100 10 nm. It will be located near the Italian third generation Synchrotron Light Source facility ELETTRA and will make use of the existing 1.0 GeV normal conducting Linac. To obtain the high beam brightness required by the project, the present Linac electron source will be substituted with a photocathode RF gun now under development in the framework of a collaboration between Sincrotrone Trieste (ST) and Particle Beam Physics Laboratory (PBPL) at UCLA. The new gun will use an improved design of the 1.6 cell accelerating structure already developed at PBPL, scaled to 2998 MHz. We expect that the new gun design will allow a beam brightness increase by a factor 3-4 over the older version of the device. Some technical choices of the new design, including the enhancement of the mode separation, removal of the RF tuners, full cell symmetrization to limit the dipole and quadrupole RF field as well as an improved solenoid yoke design for multipole field corrections, will be discussed.

TUPMN039	Status of the SPARC-X Project	emittance, radiation, linac, undulator	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.

TUPMN073	First Operation of a Thermionic Cathode RF Gun at NSRRC	gun, cathode, electron, linac	1088
	A. P. Lee S.-S. Chang, J.-Y. Hwang, W. K. Lau, C. C. Liang, G.-H. Luo, T.-T. Yang NSRRC, Hsinchu
	An injector system that based on rf gun technology is being constructed at NSRRC. This will be a 100 MeV beam injector that consists of an rf linac with a thermionic cathode rf gun as electron source. The superior performance and special configuration of the thermionic rf gun system made it an attractive option as a reliable pre-injector booster synchrotron. In cooperation with an alpha-magnet as low energy bunch compressor, ultra-fast electron beam pulses as short as 100 fs can be generated from the thermionic cathode rf gun for generation of intense coherent short wavelength radiations, production of femto-second electron and wavelength tunable ultra-fast X-ray pulses. First operation of the thermionic rf gun will be presented.

TUPMS003	Status of the Top-off Upgrade of the ALS	injection, radiation, booster, storage-ring	1197
	C. Steier B. J. Bailey, K. M. Baptiste, W. Barry, A. Biocca, W. E. Byrne, M. J. Chin, R. J. Donahue, R. M. Duarte, M. P. Fahmie, J. Gath, S. R. Jacobson, J. Julian, J.-Y. Jung, S. Kwiatkowski, S. Marks, R. S. Mueller, H. Nishimura, J. W. ONeill, S. Prestemon, D. Robin, S. L. Rossi, F. Sannibale, T. Scarvie, D. Schlueter, D. Shuman, G. D. Stover, CA. Timossi, T. Warwick, J. M. Weber, E. C. Williams LBNL, Berkeley, California
	Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, U. S. Department of Energy under Contract No. DE-AC02-05CH11231. The Advanced Light Source is currently being upgraded for top-off operation. This major facility upgrade will provide an improvement in brightness from soft x-ray undulators of about one order of magnitude and keep the ALS competitive with the newest intermediate energy light sources. Major components of the upgrade include making the booster synchrotron capable of full energy operation, radiation safety studies, improvements to interlocks and collimation systems, diagnostics upgrades as well as emittance improvements in the main storage ring. The project status will be discussed as well as results of major parts of the commissioning.

TUPMS029	Gamma-Ray Compton Light Source Development at LLNL	laser, electron, scattering, gun	1245
	F. V. Hartemann S. G. Anderson, C. P.J. Barty, D. J. Gibson, C. Hagmann, M. Johnson, I. Jovanovic, D. P. McNabb, M. J. Messerly, J. A. Pruet, M. Shverdin, C. Siders, A. M. Tremaine LLNL, Livermore, California
	Funding: This work was performed under the auspices of the U. S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. A new class of tunable, monochromatic gamma-ray sources capable of operating at high peak and average brightness is currently being developed at LLNL for nuclear photo-science and applications. These novel systems are based on Compton scattering of laser photons by a high brightness relativistic electron beam produced by an rf photoinjector. Key technologies, basic scaling laws, and recent experimental results will be presented, along with an overview of future research and development directions.

TUPMS091	A Theoretical Photocathode Emittance Model Including Temperature and Field Effects	emittance, electron, laser, photon	1377
	K. Jensen D. W. Feldman, P. G. O'Shea UMD, College Park, Maryland N. A. Moody LANL, Los Alamos, New Mexico J. J. Petillo SAIC, Burlington, Massachusetts
	Funding: We gratefully acknowledge funding by the Joint Technology Office and the Office of Naval Research. A recently developed model* of the emittance and brightness of a photocathode based on the evaluation of the moments of the electron emission distribution function admits an analytical solution for the zero-field and zero-temperature asymptotic model. Here, the model has been extended to account for the critical modifications of temperature and field dependence, which are tied to material issues with the cathode. Temperature impacts the nature of scattering within the photoemitter material and therefore affects quantum efficiency significantly. Field changes the emission probability at the surface barrier, and is particularly important for low work function coatings, as occur for the cesiated surfaces characteristic of our controlled porosity dispenser photocathodes. Extensions of the theoretical models shall be given, followed by an analysis of their comparison with numerical simulations of the intrinsic emittance and brightness of a photocathode. The methodology is designed to facilitate the development of photoemission models into comprehensive particle-in-cell (PIC) codes to address issues otherwise not readily treated, e.g., variation in surface coverage and topology. * K. L. Jensen, P. G. O'Shea, D. W. Feldman, and N. A. Moody, Applied Physics Letters 89, 224103 (2006).

FROAAB01	Towards a 100% Polarization in the RHIC Optically Pumped Polarized Ion Source	polarization, proton, electron, emittance	3771
	A. Zelenski J. G. Alessi, A. Kponou, J. Ritter, V. Zubets BNL, Upton, Long Island, New York
	The main depolarization factors in the multi-step spin-transfer polarization technique and basic limitations on maximum polarization in the different OPPIS (Optically-Pumped Polarized H^- Ion Source) schemes will be discussed. Detailed studies of polarization losses in the RHIC OPPIS and the source parameters optimization resulted in the OPPIS polarization increase to 86?1.5 %. This contributed to AGS and RHIC polarization increase to 65-70%.
	Slides

FRPMN069	Longitudinal Coupled-Bunch Instabilities in the CERN PS	impedance, emittance, dipole, feedback	4180
	H. Damerau S. Hancock, C. Rossi, E. N. Shaposhnikova, J. Tuckmantel, J.-L. Vallet CERN, Geneva M. Mehler GSI, Darmstadt
	Funding: Work supported by EU Design Study DIRACsecondary-Beams (contract 515873). Longitudinal coupled bunch instabilities in the CERN PS represent a major limitation to the high brightness beam delivered for the LHC. To identify possible impedance sources for these instabilities, machine development studies have been carried out. The growth rates of coupled bunch modes have been measured, and modes have been identified using mountain range data. Growth rate estimations from coupled bunch mode theory are compared to these results. It is shown that the longitudinal impedance of the broad resonance curve of the main 10 MHz RF system can be identified as the most probable source. Possible methods to improve the beam stability are analyzed together with the performance of a damping system.