First Name: B.
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Last Name: O'shea
Full Name: B. O'shea
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4 papers
| title: | Beam Dynamics in a Hybrid Standing Wave-Traveling Wave Photoinjector |
| format: | conference procceeding |
| conference: | |
| year: | 2006 |
| 11 authors: | | | | | | | | | | | |
| abstract: | We discuss the dynamics of of a photoinjector beam in a hybrid traveling wave-standing wave photoinjector. With the field profile deduced from electromagnetic simulations, it is seen that the acceleration program induces strong velocity bunching. The beam dynamics in this scenario are explored using UCLA PARMELA. With a solenoid field overlaid on the TW section one may control emittance oscillations during bunching and acceleration. It is seen that the S-band device currently under development at UCLA may produce a 1 nC, 21 MeV, 100 micron rms pulse length beam, with emittance of 3 mm-mrad. Applications of this beam for creating coherent radiation are discussed. |
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| title: | RF Design of the UCLA/INFN Hybrid SW/TW Photoinjector |
| format: | conference procceeding |
| conference: | |
| year: | 2006 |
| 9 authors: | | | | | | | | | |
| abstract: | With increasing demand for high brightness, low emittance beams for use with freeelectron lasers, Compton scattering systems and wake-field accelerator experiments, stringent requirements have been placed on the design and operation of the 1.6 cell photoinjector. The proposed hybrid photoinjector combines the BNL/UCLA/SLAC style 1.5/1.6 cell standing wave gun with a traveling wave accelerator. Our goal is an injector that meets today’s requirements and is scalable in design to meet tomorrow’s demands: emittances in the region of 1 mm-mrad for higher brightness as well as higher currents. The hybrid photoinjector also offers higher energy operation, enhanced cost effectiveness and better scalability than current designs such as integrated PWT photoinjectors and split gun/accelerating sections. The use of both SW and TW systems allows for higher gradients (Eo = 70 MV/m) in the SW gun for effective capture at lower emittances, while the lower energy acceleration in the TW sections (Eo = 13.5 MV/m) allows generation of higher energy beams which are less sensitive to space charge effects. We note the current results of simulation of beam dynamics, en,x = 3 mm-mrad, an energy spread of 1.5% with beam energies of 21 MeV at currents as high as 1.2 kA. Further we explore the possibilities of scalability to higher frequencies, analysis of coupling design, present cold test preparations and simulated RF analysis of the structure. |
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| title: | Commissioning of the UCLA Neptune X-band Deflecting Cavity and Applications to Current Profile Measurement of Ramped Electron Bunches |
| format: | conference procceeding |
| conference: | PAC07 |
| year: | 2007 |
| 5 authors: | | | | | |
| abstract: | A 9-cell standing-wave deflecting cavity has recently been constructed and installed at the UCLA Neptune Lab- oratory for use as a temporal diagnostic for the 13 MeV, 300 to 700 pC electron bunches generated by the Neptune photoinjector beamline. The cavity is a center-fed Glid- Cop structure operating in at TM110-like deflecting mode at 9.59616 GHz with a π phase advance per cell. At the maximum deflecting voltage of 530 kV, the theoretical res- olution limit of the device is 50 fs, although with current beam parameters and a RMS spot size of 460 μm the ef- fective resolution is approximately 400 fs. We discuss the operation and testing of the cavity as well as its intended application of measuring the temporal current profile of ramped electron bunches generated using the Neptune dog- leg compressor, and we present the first measurements of the electron beam current profile obtained using the deflect- ing cavity. |
| keywords: | pbpl_pub |
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| title: | The Design of a Hybrid Photoinjector for High Brightness Beam Applications |
| format: | journal article |
| year: | 2006 |
| 10 authors: | | | | | | | | | | |
| abstract: | In this paper, we illustrate the electromagnetic and beam dynamics design procedure of a new class of photoinjector, a hybrid standing/traveling wave structure. In this device a standing wave RF gun section is integrated with a downstream traveling wave structure through a coupling cell that feeds simultaneously the two sections. We discuss the advantages in RF and beam performance of the hybrid photoinjector compared to conventional systems. The electromagnetic design has been performed using the 3D electromagnetic code HFSS. Results of beam dynamics simulations in different operating conditions are also discussed. |
| keywords: | pbpl |
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