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W.A. Barletta

First Name: W.

Middle Name: A.

Last Name: Barletta

Full Name: W.A. Barletta

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16 papers
title: Progress on Plasma Lens Experiments at the Final Focus Test Beam
format: conference proceeding
conference: PAC 1995
year: 1995
34 authors: P. Kwok | Chen, P. | D. B. Cline | W. Barletta | Berridge, S. | Bugg, W. | Bula, C. | S. Chattopadhyay | Craddock, W. | Hsu, I. | R. Iverson | T. Katsouleas | Lai, P. | Leemans, W. | Liou, R. | McDonald, K. T. | D. Meyerhofer | Nakajima, K. | Nakanishi, H. | Ng, C. K. | Nishida, Y. | Norem, J. | A. Ogata | J.B. Rosenzweig | Ross, M. | Sessler, A. M. | Shintake, T. | Spencer, J. | Su, J. J. | Weidemann, A. W. | Westenskow, G. | D. Whittum | Williams, R. | J. Wurtele
abstract: The proposal to perform a series of plasma lens experiments at the Final Focus Test Beam at SLAC has been described earlier. We report on our progress towards validation of concepts involved in the experiments, including the laser ionized plasma production test, development of the supersonic gas jet as the plasma source, and study on focused beam size measurement techniques. Most importantly, the effects of background events due to plasma lenses in future linear collider detectors, such as that in the NLC, are studied in details and are shown to be within detector tolerances.
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title: Plasma Lens Experiments at the Final Focus Test Beam
format: conference proceeding
conference: PAC 1993
year: 1995
33 authors: R. Lieu | W. Barletta | S. Chattopadhyay | P. Chen | D. B. Cline | W. Craddock | W. Gabella | I. Hsu | R. Iverson | T. Katsouleas | P. Kwok | P. Lai | W. Leemans | R. Liou | D. Meyerhofer | K. Nakajima | H. Nakanishi | C. K. Ng | Y. Nishida | J. Norem | A. Ogata | S. Rajagopalan | T. Shintake | J.B. Rosenzweig | M. Ross | A. Sessler | J. Spencer | J. J. Su | N. Walker | G. Westenskow | D. Whittum | R. Williams | J. Wurtele
abstract: We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam induced tunneling ionization of a working gas - the latter which has never been observed before. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.
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title: The UCLA infrared free-electron laser
format: conference proceeding
conference: SPIE Conference on Intense Laser Beams
year: 1992
17 authors: J. W. Dodd | S. C. Hartman | S. Park | C. Pellegrini | J.B. Rosenzweig | J. A. Smolin | W. A. Barletta | D.B. Cline | R. K. Copper | J. Kolonko | J. G. Davis | G. Hairapetian | C. J. Joshi | N. C. Luhmann | S. N. Ivanchenkov | A. S. Khlebnikov | A. A. Varfolomeev
abstract: A compact 20 MeV linac with an RF laser-driven electron gun will drive a high-gain (10 cm gain length), 10.6 mu m wavelength FEL amplifier, operating in the SASE mode. FEL physics in the high-gain regime will be studied, including start-up from noise, optical guiding, sidebands, saturation, and superradiance, with emphasis on the effects important for future short wavelength operation of FELs. The hybrid undulator, designed and built at the Kurchatov Institute of Atomic Energy in the USSR has forty periods, each 1.5 cm long, the magnetic material is a hybrid combination of SmCo_5 blocks and Nd-Fe-B blocks, with vanadium-permendur yokes. The gap distance between pole-tips is fixed at 5 mm. On axis the peak value of the completed undulator's magnetic field was measured to be 7.3 kGauss (+/- 0.25%). Measurements during the conditioning phase of the RF gun for the electron beam's peak dark-current show 6 mA without the longitudinal magnetic focusing field in the gun and 34 mA with the focusing field active. The peak current from photoemission is calculated to be 200 A.
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title: The UCLA compact infrared free-electron laser
format: conference proceeding
conference: FEL 1991 13th
year: 1992
16 authors: J. W. Dodd | S. C. Hartman | S. Park | C. Pellegrini | J.B. Rosenzweig | D.B. Cline | G. Hairapetian | J. Kolonko | Smolin, J. A. | P.G. Davis | C. J. Joshi | N. Luhmann | S. N. Ivanchenkov | A. S. Khlebnikov | A. A. Varfolomeev | W. Barletta
abstract: The authors present the status of a compact infrared free-electron laser, driven by a 20 MeV, S-band linac with a photoinjector. The 60 cm long hybrid undulator has a 1.5 cm period and a field on axis of 7.3 kG. The FEL will operate at 10.6 mu m as a high-gain amplifier, to study the high-gain FEL regime including the effects of self amplified spontaneous emission, optical guiding and saturation. The linac is the prototype of the plane-wave transformer. TDA simulation of the FEL shows a gain length of 10 cm, and a saturation power of 50 MW. (18 References).
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title: Photocathode driven linac at UCLA for FEL and plasma wakefield acceleration experiments
format: conference proceeding
conference: PAC 1991
year: 1991
17 authors: S. Hartman | F. Aghamir | W. Barletta | D. B. Cline | J. Dodd | T. Katsouleas | J. Kolonko | S. Park | C. Pellegrini | J.B. Rosenzweig | Smolin, J. A. | Terrien, C. | J. Davis | G. Hairapetian | C. Joshi | N. Luhmann | D. McDermott
abstract: The UCLA compact 20-MeV/c electron linear accelerators is designed to produce a single electron bunch with a peak current of 200 A, an RMS energy spread of 0.2% or less, and a short 1.2-ps RMS pulse duration. The linac is also designed to minimize emittance growth down the beamline so as to obtain emittances on the order of 8 pi mm-mrad in the experimental region. The linac will feed two beamlines, the first will run straight into the undulator for FEL experiments while the second will be used for diagnostics, longitudinal bunch compression and other electron beam experiments. A description is given of the considerations that went into the design of the accelerating structures and the transport to the experimental areas. (8 References).
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title: Vacuum Design for a Superconducting Mini-collider
format: preprint
year: 1991
2 authors: W. Barletta | S. Monteiro
abstract: The phi factory (Superconducting Mini-Collider or SMAC) proposed for construction at UCLA is a single storage rign with circulating currents of 2A each of electrons and positrons. The small circumference exacerbates the difficulties of handling the gas load due to photo-desorption from the chamber walls. We analyze the vacuum system for the phi factory to specify design choices.
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title: Design of the Vacuum System for the High Energy Ring of an Asymmetric B-Factory Based on PEP
format: preprint
year: 1991
4 authors: W. Barletta | M. Calderon | R. Wong | T. Jenkins
abstract: The multi-ampere currents required for high luminosity operation of an asymmetric B factory leads to extremely stressing requirements on a vacuum system suitable for maintaining long beam-gas lifetimes and acceptable background levels in the dtector. We present the design for a Cu alloy vacuum chamber and its associated pumping system for the 9GeV electron storage ring of the proposed B factory based on PEP. The excellent thermal and photo-desorption properties of Cu allows handling the high photon flux in a conventional, single chamber design with distributed ion pumps. The x-ray opacity of the Cu is sufficiently high that no additional lead shielding is necessary to protect the dipoles from the intense synchrotron radtiation generated by the beam. The design allows chamber commissioning in <500 hr of operation.
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title: Saturnus: the UCLA infrared free-electron laser project
format: conference proceeding
conference: PAC 1991
year: 1991
17 authors: J. W. Dodd | S. C. Hartman | S. Park | C. Pellegrini | J.B. Rosenzweig | Smolin, J. A. | G. Hairapetian | J. Kolonko | W. Barletta | D.B. Cline | J. G. Davis | C. J. Joshi | N. Luhmann | S. N. Ivanchenkov | A. S. Khlebnikov | Lachin, Y. Y. | A. A. Varfolomeev
abstract: A compact 20-MeV linac with an RF laser-driven electron gun will be used to drive a high-gain (10-cm gain length), 10.6- mu m wavelength FEL (free-electron laser) amplifier, operating in the SASE mode. Saturnus will mainly be used to study FEL physics in the high-gain regime, including start-up from noise, optical guiding, sidebands, saturation, and superradiance, with emphasis on the effects important for future short-wavelength operation of FELs. The primary magnetic flux is provided by C-shaped iron yokes, where between the poles thin blocks of neodymium-iron-boron magnets are placed to provide additional magnetic flux along the undulator axis. (9 References).
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title: Preliminary conceptual design for a 510 MeV electron/positron injector for a UCLA phi factory
format: conference proceeding
conference: PAC 1991
year: 1991
4 authors: G. Dahlbacka | Hartline, R. | W. Barletta | C. Pellegrini
abstract: UCLA (University of California at Los Angeles) is proposing a compact superconducting high-luminosity (10(32-33)/ cm(-2)/ s(-1)) e+ e- collider for a phi factory. To achieve the required e+ e- currents, full energy injection from a linac with intermediate storage in a positron accumulator ring (PAR) is used. The elements of the linac are outlined with cost and future flexibility in mind. The preliminary conceptual design starts with a high current gun similar in design to those developed at SLAC and at ANL (for the APS). Four 4-section linac modules follow, each driven by a 60-MW klystron with a 1- mu s macropulse and an average current of 8.6 A. The first 4-section module is used to create positrons in a tungsten target at 186 MeV. The remaining three modules are used to accelerate the e+ e- beam to 558 MeV (no load limit) for injection into the PAR. (0 References).
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title: A high luminosity superconducting mini collider for phi meson production and particle beam physics
format: conference proceeding
conference: PAC 1991
year: 1991
14 authors: C. Pellegrini | D. Robin | D. B. Cline | J. Kolonko | S. Anderson | W. Barletta | Chargin, A. | M. Cornacchia | Dalbacka, G. | K. Halbach | Lueng, E. | Kimball, F. | Madura, D. | Patterson, L.
abstract: A 510-MeV electron-positron collider has been proposed at the University of California at Los Angeles to study particle beam physics and phi-meson physics at luminosities larger than 1032 cm/sup -2/s/sup -1/. The collider consists of a single compact superconducting storage ring (SMC), with a bending field of 4 T and a current larger than 1 A. A discussion is presented of the main characteristics of this system and its major technical components: superconducting dipoles and the RF vacuum and injection systems. (6 References).
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title: Modeling Photo-desorption in High Current Storage Rings
format: preprint
year: 1991
1 author: W. Barletta
abstract: A phenomenological model of photo-desorption that includes effects of dose dependence and diffuse photon reflection allows one to compute the leveling of gas loads high current storage rings that typify heavy flavor factories. The model also permits one to estimate chamber commissioning times.
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title: Saturnus: the UCLA compact infrared free-electron laser project
format: conference proceeding
conference: Intense Microwave and Particle Beams II
year: 1991
16 authors: J. W. Dodd | F. Aghamir | W. Barletta | D. B. Cline | S. C. Hartman | T. C. Katsouleas | J. Kolonko | S. Park | C. Pellegrini | P. G. Davis | C. J. Joshi | N. C. Luhmann | D. B. McDermott | S. N. Ivanchenkov | YuYu Lachin | A. A. Varfolomeev
abstract: Saturnus is an infrared FEL operating in the 10 mu m wavelength region, driven by a compact 20 MeV linac with a photoinjector, under construction at UCLA. The 1.5 cm period, 0.6 T peak field undulator is being built at the Kurchatov IAE. The FEL is designed to operate primarily in the self amplified spontaneous emission mode. The authors plan to study the start-up from noise, optical guiding, saturation, sidebands and superradiance, with emphasis on the effects important for future short wavelength operation of FEL's. The photoinjector follows closely the Brookhaven design. Electrons are injected into an accelerating section based on the plane-wave-transformer design developed by Swenson at SAIC. Simulation of the linac and FEL show a gain length of 10 cm, and a saturation power of 50 MW. (13 References).
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title: Saturnus: the UCLA high-gain infrared FEL project
format: conference proceeding
conference: FEL 1990 12th
year: 1991
17 authors: F. Aghamir | W. Barletta | D.B. Cline | J. W. Dodd | S. C. Hartman | T.C. Katsouleas | J. Kolonko | S. Park | C. Pellegrini | Terrien, C. | J. G. Davis | C. J. Joshi | N. Luhmann | D. B. McDermott | S. N. Ivanchenkov | Lachin, Y. Y. | A. A. Varfolomeev
abstract: The authors present the status of Saturnus: an infrared FEL operating in the 10 mu m wavelength region, driven by a compact 20 MeV linac with a photoinjector, under construction at UCLA. The 1.5 cm period, 0.5 T peak-field undulator is being built at the Kurchatov IAE. The FEL is being designed to operate primarily in the self-amplified spontaneous emission mode. They plan to study the startup from noise, optical guiding, saturation, sidebands and superradiance, with emphasis on the effects important for future short-wavelength operation of FELs. The photoinjector follows closely the Brookhaven design. Electrons are injected into an accelerating section based on the plane-wave transformer design developed by Swenson at SAIC. Simulation of the linac and FEL show a gain length of 10 cm, and saturation power of 50 MW. (10 References).
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title: A full energy positron source for the UCLA phi factory
format: conference proceeding
conference: Workshop on Testing CPT and Studying CP Violation at a Phi Factory
year: 1991
2 authors: W. Barletta | C. Pellegrini
abstract: The authors describe a full energy injection system suitable for rapid filling of a compact phi factory with high luminosity. Several novel approaches are suggested to minimize power on the positron target and to allow single bunch injection of electrons. (4 References).
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title: The UCLA IR-FEL
format: conference proceeding
conference: IEEE International Conference on Plasma Science 1990
year: 1990
11 authors: F. Aghamir | W. Barletta | D. B. Cline | J. Dodd | S. Hartman | C. Joshi | J. Kolonko | N. Luhmann | D. McDermott | C. Pellegrini | C. Terrien
abstract: A high-brightness RF gun operating at 2.856 GHz is being used as the injector for an IR-FEL (free-electron laser) experiment. The RF gun consists of a disk loaded, 1.5 cell cavity and a photocathode in the end wall of the cavity. A strong electric field within the half cell near the photocathode quickly accelerates the electrons, thus preventing emittance blow-up. The photocathode is to be driven by a Nd:YAG laser system producing a 10-ps pulse. The power for the RF gun will be supplied by a 25-MW klystron. The RF power is coupled to the cavity via an S-band waveguide attached to the sidewall of the gun. The TE_10 mode excited in the waveguide strongly couples to the pi-mode with the RF gun while the zero mode is suppressed. (0 References).
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title: A linear collider phi factory and beam dynamics test machine
format: conference proceeding
conference: Workshop on CP Violation in Particle Physics and Astrophysics
year: 1990
8 authors: W.A. Barletta | R. C. Berg | A. Boden | C. Buchanan | D.B. Cline | A. Fridman | C. H. Ho | C. Pellegrini
abstract: The authors present the design of a high luminosity linear collider phi factory. This machine can be used to search for violation of CPT invariance and the study of CP violation (epsilon). It can also serve as a test collider to study the feasibility of L > 10(34) cm(-2) sec(-1) BB factory and the beam dynamics of large disruption systems. The machine will be asymmetric in beam energy, thus giving the phi's a boost.
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