11 papers
| title: | Virtual dielectric waveguide mode description of a high-gain free-electron laser. II. Modeling and numerical simulations |
| format: | journal article |
| year: | June 20, 2008 |
| 3 authors: | | | |
| abstract: | A high-gain free-electron laser is modeled using an expansion of the radiation field in terms of guided Laguerre-Gaussian modes of a virtual dielectric waveguide E. Hemsing, A. Gover, and J. Rosenzweig, preceding paper, Phys Rev. A 77, 063830 2008 . The radiation profile evolution, power gain, and detuning efficiency characteristics are investigated for seeding with fundamental Gaussian and higher-order Laguerre- Gaussian input modes on a Gaussian e-beam in the collective regime. The full wave evolution solution at different seed radiation injection conditions results in determination of the optimal waist size and waist position of the seed radiation beam for maximum power coupling efficiency. Results for guided mode evolution and power gain are shown to be consistent with simulations performed with the code GENESIS 1.3. The amplification and spontaneous generation of FEL radiation with orbital angular momentum is also considered. |
| keywords: | pbpl   pra   |
| Download | View | Details | edit | delete | |
| title: | Dielectric Wakefield Accelerator Experiments at the Saber Facility |
| format: | conference procceeding |
| conference: | PAC07 |
| year: | 2007 |
| 17 authors: | | | | | | | | | | | | | | | | | |
| abstract: | Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC Final Focus Test Beam (FFTB), are foreseen to be produced at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of multi-GV/m in plasmas. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 um and 200 um ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in fused silica (with full data analysis still ongoing) [1]. With the construction and commissioning of the SABER facility at SLAC, new experiments would be made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and proof of acceleration in tubes >10 cm in length. This collaboration will investigate breakdown thresholds and accelerating fields in new materials including CVD diamond. Here we describe the experimental plans, beam parameters, simulations, and progress to date as well as future prospects for machines based of DWA structures. |
| keywords: | pbpl_pub   |
| Download | View | Details | edit | delete | |
| title: | Status of the Fermi@Elettra Photoinjector |
| format: | conference procceeding |
| conference: | EPAC 2008 |
| year: | 2008 |
| 21 authors: | | | | | | | | | | | | | | | | | | | | | |
| abstract: | The new FERMI@Elettra photoinjector is presently undergoing high-power testing and characterization at MAXlab in Lund, Sweden. This effort is a collaboration between Sincrotrone Trieste, MAX-lab and UCLA. The 1.6-cell RF gun cavity and the focusing solenoid were successfully designed and built by the Particle Beam Physics Laboratory at UCLA, delivered to Sincrotrone Trieste at the beginning of 2008, and installed in the linac tunnel at MAX-lab. Use of the MAX-lab facility will allow the FERMI project to progress significantly with the photoinjector while waiting for the completion of the new linac building extension at Sincrotrone Trieste. We report here on the high-power conditioning of the RF cavity and the first beam tests. |
| keywords: | pbpl_pub   |
| Download | View | Details | edit | delete | |
| title: | A Novel Fabrication Technique for the Production of RF Photoinjectors |
| format: | conference procceeding |
| conference: | EPAC 2008 |
| year: | 2008 |
| 9 authors: | | | | | | | | | |
| abstract: | Recent developments in Solid Freeform Fabrication (SFF) technology may make it possible to design and produce near netshape copper structures for the next generation of very high duty factor, high gradient radio frequency (RF) photoinjectors. RF and thermal management optimized geometries could be fully realized without the usual constraints and compromises of conventional machining techniques. A photoinjector design incorporating SFF and results from an initial material feasibility study will be reported. |
| keywords: | pbpl_pub   |
| Download | View | Details | edit | delete | |
| title: | Design and Fabrication of an X-Band traveling wave deflection mode cavity for longitudinal characterization of ultra-short electron beam pulses |
| format: | conference procceeding |
| conference: | EPAC 2008 |
| year: | 2008 |
| 9 authors: | | | | | | | | | |
| abstract: | An X-band Traveling wave Deflector mode cavity (XTD) has been developed at Radiabeam Technologies to perform longitudinal characterization of the subpicosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. An XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, fabrication procedure, and commissioning plans are presented. An experimental program at ATF to utilize the deflector for compressed beam characterization is discussed, including proposed measurements of the phase space filamentation due to non-linear processes in a chicane compressor. |
| keywords: | pbpl_pub   |
| Download | View | Details | edit | delete | |
| title: | Recent results and future perspectives of the SPARC project |
| format: | conference procceeding |
| conference: | EPAC 2008 |
| year: | 2008 |
| 77 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | The SPARC project foresees the realization of a high brightness photo-injector to produce a 150-200 MeV electron beam to drive 500 nm FEL experiments in various configurations, a Thomson backscattering source and a plasma accelerator experiment (these last two ones jointly with the project PLASMONX). The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. As a first stage of the commissioning, a complete characterization of the photoinjector has been accomplished with a detailed study of the emittance compensation process downstream the gun-solenoid system: this lead to the first direct experimental demonstration of emittance oscillations in a drift. The second stage of the commissioning, that is currently underway, foresees a detailed analysis of the beam matching with the linac in order to confirm the theoretically prediction of emittance compensation based on the “invariant envelope” matching and the demonstration of the “velocity bunching” technique in the linac. SASE and SEEDING experiments are foreseen by the end of the current year. In this paper we report the experimental results obtained so far and the scientific program for the near future. |
| keywords: | pbpl_pub   |
| Download | View | Details | edit | delete | |
| title: | The UCLA Helical Permanent-Magnet Inverse Free Electron Laser |
| format: | conference procceeding |
| conference: | PAC07 |
| year: | 2007 |
| 7 authors: | | | | | | | |
| abstract: | The Inverse Free Electron Laser (IFEL) is capable, in principle, of reaching accelerating gradients of up to 1 GV/m making it a prospective accelerator scheme for linear colliders. The Neptune IFEL at UCLA utilizes a 15 MeV Photoinjector-generated electron beam of 0.5 nC and a CO2 laser with peak energy of up to 100 J, and will be able to accelerate electrons to 100 MeV over an 80 cm long, novel helical permanent-magnet undulator. Past IFELs have been limited in their average accelerating gradient due to the Gouy phase shift caused by tight focusing of the drive laser. Here, laser guiding is implemented via an innovative Open Iris-Loaded Waveguide Structure (OILS) scheme which ensures that the laser mode size and wave front are conserved through the undulator. The results of the first phase of the experiment are discussed in this paper, including the design and construction of a short micro-bunching undulator, testing of the OILS waveguide, as well as the results of corresponding simulations. |
| keywords: | pbpl_pub   |
| Download | View | Details | edit | delete | |
| title: | High Average Current Betatrons for Industrial and Security Applications |
| format: | conference procceeding |
| conference: | PAC07 |
| year: | 2007 |
| 8 authors: | | | | | | | | |
| abstract: | The fixed-field alternating-gradient (FFAG) betatron has emerged as a viable alternative to RF linacs as a source of high-energy radiation for industrial and security applications. For industrial applications, high average currents at modest relativistic electron beam energies, typically in the 5 to 10 MeV range, are desired for medical product sterilization, food irradiation and materials processing. For security applications, high power x-rays in the 3 to 20 MeV range are needed for rapid screening of cargo containers and vehicles. In a FFAG betatron, high-power output is possible due to high duty factor and fast acceleration cycle: electrons are injected and accelerated in a quasi-CW mode while being confined and focused in the fixed-field alternating- gradient lattice. The beam is accelerated via magnetic induction from a betatron core made with modern low- loss magnetic materials. Here we present the design and status of a prototype FFAG betatron, called the Radiatron, as well as future prospects for these machines. |
| keywords: | pbpl_pub   |
| 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 | |
| title: | Single spike operation in SPARC SASE-FEL |
| format: | conference procceeding |
| conference: | EPAC 2008 |
| year: | |
| 16 authors: | | | | | | | | | | | | | | | | |
| abstract: | The single spike operation regime has been analyzed in the case of the SPARC injector and freeelectron-laser. Four different beams at 50 pC are studied, with different production condition and performance. |
| keywords: | pbpl_pub   |
| Download | View | Details | edit | delete | |
| title: | Quasi-crystalline beam (QCB) formation in strongly accelerating intense electron distributions |
| format: | talk |
| year: | |
| 1 author: | |
| abstract: | QUASI-CRYSTALLINE BEAM (QCB) FORMATION IN STRONGLY ACCELERATING INTENSE ELECTRON DISTRIBUTIONS Prof. J. Rosenzweig Frascati, LNF, June 12, 2008 |
| keywords: | pbpl_talk   |
| Download | View | Details | edit | delete | |