Name: 2005 Particle Accelerator Conference
Location: Knoxville, TN, USA
Date: 2005-05-01
Comments: http://neutrons.ornl.gov/pac05/
Created at:
Updated at: Thu Jun 21 11:31:16 -0700 2007
Edit | Back | Add Paper| title: | X-Band Dipole Mode Deflecting Cavity for the UCLA Neptune Beamline |
| format: | conference procceeding |
| conference: | 2005 Particle Accelerator Conference |
| year: | 2005 |
| 5 authors: | | | | | |
| abstract: | We report progress on the design and construction of a nine-cell cavity operating in a TM110-like dipole mode for use as a temporal diagnostic of the 14 MeV, 300 pC electron bunches generated at the UCLA Neptune Laboratory linear accelerator, with an anticipated temporal resolution of 50 fs at a peak input power of 50 kW. The cavity is a center-fed standing-wave pi-mode structure, operating at 9.6 GHz, and incorporating a knife-edge and gasket assembly which minimizes the need for brazing or welding. Results of initial RF testing of the prototype cavity are discussed and compared with simulation results obtained using the commercial code HFSS. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Recent Results from and Future Plans for the VISA II SASE FEL |
| format: | conference procceeding |
| conference: | 2005 Particle Accelerator Conference |
| year: | 2005 |
| 19 authors: | | | | | | | | | | | | | | | | | | | |
| abstract: | The VISA II (Visible to Infrared SASE Amplifier) project, a consequent experiment to the succesful VISA enterprise, entails the use of a chirped electron beam to drive a high gain SASE FEL. The resulting ultra-short pulses will be characterized using an advanced FROG (Frequency Resolved Optical Gating) technique, as well as a double differential spectrum (angle/wavelength) diagnostic. Implementation of sextupole corrections to the longitudinal aberrations affecting the high energy-spread chirped beam during transport to the VISA undulator is studied. Start-end simulations, including radiation diagnostics, are discussed. Initial experimental results involving a highly chirped beam transported without sextupole corrections, the resulting high gain lasing, and computational analysis are briefly reported. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Production of High Harmonic X-ray Radiation from Non-linear Thomson Scattering at LLNL PLEIADES |
| format: | conference procceeding |
| conference: | 2005 Particle Accelerator Conference |
| year: | 2005 |
| 11 authors: | | | | | | | | | | | |
| abstract: | We describe an experiment for production of high harmonic x-ray radiation from Thomson backscattering of an ultra-short high power density laser by a relativistic electron beam at the PLEIADES facility at LLNL. In this scenario, electrons execute a ``figure-8'' motion under the influence of the high-intensity laser field, where the constant characterizing the field strength is expected to exceed unity: $a_{L}=eE_{L}/m_{e}c\omega_{L}\geq1$. With large $a_{L}$ this motion produces high harmonic x-ray radiation and significant broadening of the spectral peaks. This paper is intended to give a layout of the PLEIADES experiment, along with progress towards experimental goals. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | RF AND MAGNETIC MEASUREMENTS ON THE SPARC PHOTOINJECTOR AND SOLENOID AT UCLA |
| format: | conference procceeding |
| conference: | 2005 Particle Accelerator Conference |
| year: | 2005 |
| 8 authors: | | | | | | | | |
| abstract: | The rf photocathode gun and the solenoid for the SPARC project at INFN-LNF (Frascati) have been fabricated and undergone initial testing at UCLA. The advanced aspects of the design of these devices are detailed. Final diagnosis of the tuning of the RF gun performance, including operating mode frequency and field balance, is described. The emittance compensating solenoid magnet, which is designed to be tuned in longitudinal position by differential excitation of the coils, has been measured using Hall probe scans for field profiling, and pulsed wire methods to determine the field center. Comparisons between measurements and the predictions of design codes are made. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Ultra-High Density Electron Beams for Beam Radiation and Beam Plasma Interaction |
| format: | conference procceeding |
| conference: | 2005 Particle Accelerator Conference |
| year: | |
| 11 authors: | | | | | | | | | | | |
| abstract: | Current and future applications of high brightness electron beams, which include advanced accelerators such as the plasma wake-field accelerator (PWFA) and beam radiation interactions such as inverse-Compton scattering (ICS), require both transverse and longitudinal beam sizes on the order of tens of microns. Ultra-high density beams may be produced at moderate energy (50 MeV) by compression and subsequent strong focusing of low emittance, photoinjector sources. We describe the implementation of this method used at the PLEIADES ICS x-ray source in which the photoinjector-generated beam has been compressed to 300 fsec duration using the velocity bunching technique and focused to 20 um rms size using an extremely high gradient, permanent magnet quadrupole (PMQ) focusing system. |
| keywords: | pbpl |
| Download | View | Details | edit | delete | |
| title: | Feasibility Study of a Laser Beat-Wave Seeded THz FEL at the Neptune Laboratory |
| format: | journal article |
| year: | 2005 |
| 6 authors: | | | | | | |
| abstract: | |
| keywords: | pbpl |
| Details | edit | delete | |
| title: | HIgh Energy, High Brightness X-Rays Produced by Compton Back Scattering at the Livermore PLEIADES facility |
| format: | journal article |
| year: | |
| 11 authors: | | | | | | | | | | | |
| abstract: | PLEIADES (Picosecond Laser Electron Interaction for the Dynamic Evaluation of Structures) produces tunable 30-140 keV x-rays with 0.3-5 ps pulse lengths and up to 10^7 photons/pulse by colliding a high brightness electron beam with a high power laser. The electron beam is created by an rf photo-injector system, accelerated by a 120 MeV linac, and focused to 20 μm with novel permanent magnet quadrupoles. To produce Compton back scattered x-rays, the electron bunch is overlapped with a Ti:Sapphire laser that delivers 500 mJ, 100 fs, pulses to the interaction point. K-edge radiography at 115 keV on Uranium has verified the angle correlated energy spectrum inherent in Compton scattering and high-energy tunability of the Livermore source. Current upgrades to the facility will allow laser pumping of targets synchronized to the x-ray source enabling dynamic diffraction and time-resolved studies of high Z materials. Near future plans include extending the radiation energies to >400 keV, allowing for nuclear fluorescence studies of materials. |
| keywords: | pbpl |
| Download | View | Details | edit | delete | |
| title: | Production of Terahertz Seed Radiation for FEL/IFEL Microbunchers for Second Generation Plasma Beatwave Experiments at Neptune |
| format: | journal article |
| year: | 2005 |
| 5 authors: | | | | | |
| abstract: | To achieve phase locked injection of short electron bunches in a plasma beatwave accelerator, the Neptune Laboratory will utilize microbunching in an FEL or IFEL system. These systems require terahertz (THz) seed radiation on the order of 10 kW for the FEL and 10 MW for the IFEL bunchers. We report results of experiments on THz generation using nonlinear frequency mixing of CO2 laser lines in GaAs. A two-wavelength laser beam was split and sent onto a 2.5 cm long GaAs crystal cut for noncollinear phase matching. Low power measurements achieved ~1 W of 340 μm radiation using 200 ns CO2 pump pulses with wavelengths 10.3μm and 10.6μm. We also demonstrated tunability of difference frequency radiation, producing 240μm by mixing two different CO2 laser lines. By going to shorter laser pulses and higher intensities, we were able to increase the conversion efficiency while decreasing the surface damage threshold. Using 200ps pulses we produced ~2 MW of 340 μm radiation. Future studies in this area will focus on developing large diameter Quasi-Phase matched structures for production of high power THz radiation using collinear two frequency radiation. |
| keywords: | pbpl |
| Download | View | Details | edit | delete | |
| title: | The UCLA/FNPL Time Resolved Underdense Plasma Lens Experiment |
| format: | journal article |
| year: | 2005 |
| 11 authors: | | | | | | | | | | | |
| abstract: | A gaussian underdense plasma lens with peak density 5 × 1012cm-3and a full width half maximum (FWHM) length of 2.2 cm has been used to focus a relativistic electron beam. This plasma lens has a focusing strength equivalent to a quadrupole magnet with a 150 T/m field gradient. The lens focused a 15 MeV, 16 nC electron beam with initial dimensions σr= 500 μm and σz= 5 mm onto an optical transition radiation (OTR) screen 2 cm downstream of the lens. The average transverse area of the plasma focused electron beam was typically demagnified by a factor of 22. The light from the OTR screen was imaged into a streak camera in order to directly measure the correlation between z and σrwithin the beam. |
| keywords: | pbpl |
| Download | View | Details | edit | delete | |
| title: | Experimental Characterization of 4-D Transverse Phase-Space of a Compressed Beam |
| format: | journal article |
| year: | 2005 |
| 8 authors: | | | | | | | | |
| abstract: | |
| keywords: | pbpl |
| Details | edit | delete | |