| Paper | Title | Page |
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| TUPMN028 | The New Photoinjector for the Fermi Project | 974 |
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| 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. | ||
| TUPMS028 | Commissioning of a High-Brightness Photoinjector for Compton Scattering X-Ray Sources | 1242 |
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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 No. W-7405-Eng-48. Compton scattering of intense laser pulses with ultra-relativistic electron beams has proven to be an attractive source of high-brightness x-rays with keV to MeV energies. This type of x-ray source requires the electron beam brightness to be comparable with that used in x-ray free-electron lasers and laser and plasma based advanced accelerators. We describe the development and commissioning of a 1.6 cell RF photoinjector for use in Compton scattering experiments at LLNL. Injector development issues such as RF cavity design, beam dynamics simulations, emittance diagnostic development, results of sputtered magnesium photo-cathode experiments, and UV laser pulse shaping are discussed. Initial operation of the photoinjector is described and transverse phase space measurements are presented. |
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| TUPMS035 | The FINDER Photoinjector | 1260 |
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| The FINDER project at LLNL is an inverse-Compton scattering demonstration, aimed at creating MeV-class, narrow band photons for interrogation of nuclear materials. The requirements experiment requires a state-of-the-art photoinjector. Such a device is under development by a UCLA/LLNL collaboration. We report on a number of design innovations, such as photocathode gun RF symmetrization and large mode separation, which sets this device apart from previous generations of the BNL/SLAC/UCLA 1.6 cell gun. Measurements characterizing the RF photocathode gun and emittance compensation solenoid are presented. | ||
| WEPMS035 | Measurement of the UCLA/URLS/INFN Hybrid Gun | 2418 |
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Funding: This work performed under the auspices of the U. S. Department of Energy under contract numbers DE-FG-98ER45693 and DE-FG03-92ER40693. The hybrid photoinjector is a high current, low emittance photoinjector/accelerator and is under design and collaboration at Roma University La Sapienza, INFN - Laboratori Nazionali di Frascati and the UCLA Particle Beam Physics Lab. The hybrid standing wave-traveling wave photoinjector uses a coupling cell to divide power between a high-field 1.6 cell standing wave photoinjector, for electron emission and collection, and a low power traveling wave accelerator, for acceleration to desired energies at low emittances. Simulation results show promising beam properties of less than 4 mm-mrad emittance, energy spreads of 1.5%, and currents as high as 1.2 kA at energies of 21 MeV. We report on the progress of RF design and results of cold test RF measurements at the UCLA Pegasus Laboratory, including methods for measurements and difficulties arising in the transition from simulation to physical measurements. |
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| THPAS052 | Charge and Wavelength Scaling of the UCLA/URLS/INFN Hybrid Photoinjector | 3609 |
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| Short-bunched beam is required for the improving the emission of the free electron laser and wakefield accelerations, as well as low emittance beam. To achieve both of short length and low emittance, we are developing SW/TW Hybrid gun. Two standing wave cells make a photocathode RF gun and the gun is connected directory to the input coupler of the traveling wave structure, and the total length is about 3 m. The low emittance beam produced in the RF gun is bunching in the traveling wave structure in the scheme of, so called, "velocity bunching". PARMELA simulation shows that 1 nC bunch can be achieve 3.0 mm.mrad for the normalized rms emittance and 0.14 mm for the rms bunch length, simultaneously. We also calculates the cases of 1 pC bunch in S-band and 250 pC bunch in X-band to get shorter bunch length and lower emittance. 1 pC bunch is scaled to 1/1000 in its volume (one-tenth for each dimension). It can result in 0.0047 mm short while the emittance is 0.091 mm.mrad. In X-band case, where the structures are scaled down one-fourth in the length and four times in the field strength, the bunch length and the emittance are 0.027 mm and 1.1 mm.mrad, respectively. |