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12 papers
| title: | An Adjustable Permanent Magnet Quadrupole Final Focus System for Low Energy Experiments |
| format: | conference procceeding |
| conference: | 2003 Particle Accelerator Conference |
| year: | 2003 |
| 7 authors: | | | | | | | |
| abstract: | The final focus system for the Thomson X-ray scattering experiment termed PLEIADES (Picosecond Laser-Electron InterAction for Dynamic Evaluation of Structures) at LLNL demands ultra-high field gradient quadrupoles in order to focus initially small beams to 10-20 micron spot sizes. This scheme circumvents limitations due to chromatic aberrations and space-charge effects in this relatively low energy (<100 Mev) system. The final focus scheme is based on an ultra-high gradient (300T/m) quadrupole which employs the Halbach 16-piece, permanent magnet design. Use of this optimized goemetry, NdFeB material, and a small (4 mm) bore allows the desired field gradient, and few cm focal length, to be achieved. The adjustability of the focusing system is obtained by changing the relative longitudinal positions of sub-component focusing and defocusing magnets on precision movers. We present the results of RADIA 3D design simulations, and measurement of prototype magnets. We also discuss the results of beam dynamics simulations of the PLEIADES system using both envelope and tracking codes. |
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| title: | Design and Operation of Pegasus Thermionic Cathode |
| format: | conference procceeding |
| conference: | 2003 Particle Accelerator Conference |
| year: | 2003 |
| 6 authors: | | | | | | |
| abstract: | A new thermionic cathode has been developed and installed for use on The PEGASUS plane wave transformer injector. The novel design of the LaB6 cathode allows for thermionic emission as well as photoinjector operation. Test stand measurements as well as in situ operational experience are reported. |
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| title: | Status of the UCLA PEGASUS Laboratory |
| format: | conference procceeding |
| conference: | 2003 Particle Accelerator Conference |
| year: | 2003 |
| 6 authors: | | | | | | |
| abstract: | The PEGASUS laboratory is a versatile radiation facility dedicated to the advancement of novel concepts in beam physics. The installation of a new LaB$_6$ cathode will allow for both thermionic emission and photoinjection operation. The PEGASUS plane wave transformer injector has been conditioned to 20 MW of RF power. Recent operations show a 15 MeV dark current beam that will be used for beam radiation studies. An upgrade to the drive laser system has been explored and will be realized shortly. This paper will describe and report the status of the various subsystems of the PEGASUS laboratory and outline the experiments underway, such as innovative beam instrumentation, surface effects in optical transition radiation, Thomson scattering, and waveguide SASE FEL. |
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| title: | The UCLA Pegasus Plane-Wave Transformer Photoinjector |
| format: | conference procceeding |
| conference: | 2003 Particle Accelerator Conference |
| year: | 2003 |
| 6 authors: | | | | | | |
| abstract: | A photoinjector based on a multicell plane wave transformer accelerating structure has been commissioned at the UCLA Department of Physics' Pegasus Laboratory. Design and construction of the novel structure have been previously reported [J. Rosenzweig, et al. PAC Proceedings 1997], and recent operation with a thermionic cathode is being presented at this conference [P. Frigola, et al. these proceedings]. This paper describes the planned operation of the PWT gun as a photoinjector, including design and construction details of the drive laser. Progress to date and future plans are discussed. |
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| title: | The FEL Program at the PEGASUS Injector |
| format: | conference procceeding |
| conference: | 2003 Particle Accelerator Conference |
| year: | 2003 |
| 6 authors: | | | | | | |
| abstract: | The PEGASUS photo injector at UCLA can produce a photo electrons beam with a normalized emittance of 2 mm mrad at an energy of 12-15 MeV, capable of driving a Free-Electron Laser in the mid IR regime. The FEL program, associated with the PEGASUS injector and presented here, is based on a Self-Amplifying Spontaneous Emission (SASE) FEL. The studies focus on increasing the efficiency of an FEL by novel undulator design and compensation of diffraction effects, using waveguides of millimeter size. In this presentation we also discuss the possibility of the PEGASUS FEL as a THz user facility. |
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| title: | Status of the UCLA PEGASUS Injector Laboratory |
| format: | conference procceeding |
| conference: | 24th International Free Electron Laser Conference |
| year: | 2003 |
| 6 authors: | | | | | | |
| abstract: | The PEGASUS plane wave transformer injector has been conditioned to 20 MW of RF power. Initial operations show a 15 MeV dark current beam that will be used for beam radiation studies. The design of a new LaB_6 cathode will allow for both thermionic emission and photoinjection operation. Experiments currently planned include novel beam instrumentation, surface effects in optical transition radiation, and waveguide SASE FEL. |
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| title: | Commissioning of the UCLA PEGASUS Photoinjector Laboratory |
| format: | conference procceeding |
| conference: | 2001 Particle Accelerator Conference |
| year: | 2001 |
| 5 authors: | | | | | |
| abstract: | The PEGASUS Photoinjector has been commissioned at UCLA. The Plane Wave Transformer Photoinjector provides a high-brightness 17 MeV beam that will be used for numerous beam-radiation studies. Some of these will include SASE FEL, transition radiation from non-standard surfaces, and monochromatic x-ray production via PXR and Thompson scattering. |
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| title: | Proposal for a IR Waveguide SASE FEL at the PEGASUS Injector |
| format: | conference procceeding |
| conference: | 2001 Particle Accelerator Conference |
| year: | 2001 |
| 3 authors: | | | |
| abstract: | Free Electron Lasers up to the visible regime are dominated by diffraction effects, resulting in a radiation size much larger than the electron beam. Thus the effective field amplitude at the location of the electron beam, driving the FEL process, is reduced. By using a waveguide, the radiation field is confined within a smaller aperture and an enhancement of the FEL performance can be expected. The PEGASUS injector at UCLA will be capable to provide the brilliance needed for an IR SASE FEL. The experiment PERSEUS (Power Enhanced Radiation Source Experiment Using Structures) is proposed to study the physics of a waveguide SASE FEL in a quasi 1D environment, where diffraction effects are strongly reduced as it is the case only for future FELs operating in the VUV and X-ray regime. The expected FEL performance is given by this presentation. |
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| title: | The PEGASUS free electron laser laboratory |
| format: | conference procceeding |
| conference: | 22nd International Free Electron Laser Conference |
| year: | 2001 |
| 4 authors: | | | | |
| abstract: | The PEGASUS (Photoelectron Generated Amplified Spontaneous Radiation Source) free electron laser laboratory is currently being commissioned at UCLA. |
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| title: | Proposal for a IR waveguide SASE FEL at the PEGASUS injector |
| format: | conference procceeding |
| conference: | 22nd International Free Electron Laser Conference |
| year: | 2001 |
| 3 authors: | | | |
| abstract: | Free Electron Lasers up to the visible regime are dominated by diffraction effects, resulting in a radiation size much larger than the electron beam. Thus the effective field amplitude at the location of the electron beam, driving the FEL process, is reduced. By using a waveguide, the radiation field is confined within a smaller aperture and an enhancement of the FEL performance can be expected. The PEGASUS injector at UCLA will be capable to provide the brilliance needed for an IR SASE FEL. The experiment Power Enhanced Radiation Source Experiment Using Structures (PERSEUS) is proposed to study the physics of a waveguide SASE FEL in a quasi I D environment, where diffraction effects are strongly reduced as it is the case only for future FELs operating in the VUV and X-ray regime. The expected FEL performance is given by this presentation. |
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| title: | Initial operation of S-band plane wave transformer photoinjector |
| format: | conference procceeding |
| conference: | APS April Meeting |
| year: | 2000 |
| 4 authors: | | | | |
| abstract: | An integrated S-Band RF photoinjector based on the plane wave transformer (PWT) is being built and operated in the Particle Beam Physics Laboratory at UCLA. This novel structure integrates a photocathode directly into a PWT Linac making the structure simple and compact. Due to the strong coupling between each adjacent cell, this structure is relatively easy to fabricate and operate. This photoinjector can provide high brightness beams at energies of 15 to 20MeV, with emittance less than 1mm-mrad at charge of 1 nC. These short-pulse beams can be used in various applications: space charge dominated beam physics studies, plasma lenses, plasma accelerators, free-electron laser microbunching techniques, and SASE-FEL physics studies. It will also provide commercial opportunities in chemistry, biology and medicine. The initial operation of the PWT photoinjector with high RF power is described. A comparation of experimental result and theoretical design is also discussed. |
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| title: | The development of S-band plane wave transformer photoinjector |
| format: | conference procceeding |
| conference: | 1999 Particle Accelerator Conference |
| year: | 1999 |
| 11 authors: | | | | | | | | | | | |
| abstract: | An integrated S-band RF photoinjector based on the plane wave transformer (PWT) is being built in the Particle Beam Physics Laboratory at UCLA in collaboration with DULY Research. This novel structure integrates a photocathode directly into a PWT linac making the structure simple and compact. Due to the strong coupling between each adjacent cell, this structure is relatively easy to fabricate and operate. This photoinjector can provide high brightness beams at energies of 15 to 20 MeV, with emittance less than 1 mm-mrad at charge of 1 nC. These short-pulse beams can be used in various applications: space charge dominated beam physics studies, plasma lenses, plasma accelerators, free-electron laser microbunching techniques, and SASEFEL physics studies. It will also provide commercial opportunities in chemistry, biology and medicine. The present status of the PWT photoinjector including fabrication and cold test to characterise the structure is described. RF system and photocathode drive laser system are also discussed. |
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