| Paper |
Title |
Page |
| TUBAU04 |
Generation of Sub-fsec, High Brightness Electron Beams for Single Spike SASE FEL Operation
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214 |
| |
- J. B. Rosenzweig, M. P. Dunning, L. Faillace, A. Fukasawa, E. Hemsing, G. Marcus, A. Marinelli, P. Musumeci, B. D. O'Shea, C. Pellegrini, S. Reiche
UCLA, Los Angeles, California
- M. Boscolo, M. Ferrario, L. Palumbo, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati (Roma)
- L. Giannessi, C. Ronsivalle
ENEA C. R. Frascati, Frascati (Roma)
- V. Petrillo
Istituto Nazionale di Fisica Nucleare, Milano
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We present here the theory and computational modeling of beams in a new regime, where <1 pC beams are strongly velocity bunched at low energy, and then compressed at several GeV to less than a fsec. This regime of operation produces beams with thermally dominated transverse emittance, and mitigates many problems associated with the nC-level operation. These problems include CSR induced instability and intra-undulator wakes. The resulting beams have extremely high brightness, enabling very high gain, efficiency, and single spike operation. We present the scaling laws governing this regime, and the detailed example of the proposed SPARX FEL design.
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| TUPPH018 |
Longitudinal Diagnostic for Single-Spike SASE FEL Operation
|
274 |
| |
- G. Marcus, G. Andonian, A. Fukasawa, S. Reiche, J. B. Rosenzweig
UCLA, Los Angeles, California
- M. Ferrario, L. Palumbo
INFN/LNF, Frascati (Roma)
- L. Giannessi
ENEA C. R. Frascati, Frascati (Roma)
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The possibility of ultra-short beam, very low charge, short wavelength FELs at SPARC has been recently investigated. This paper explores the development of a longitudinal diagnostic that will provide the capability to characterize the short wavelength radiation based on the Frequency Resolved Optical Gating (FROG) technique. The paper includes studies of pulses simulated for the SPARC case using GENESIS and reconstructed using the FROG algorithm as well as proposed experimental layouts for the device.
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| TUPPH021 |
An Ultra-high Repetition Rate S-band RF Gun
|
282 |
| |
- L. Faillace, A. Fukasawa, B. D. O'Shea, J. B. Rosenzweig
UCLA, Los Angeles, California
- P. Frigola
RadiaBeam, Marina del Rey
- L. Palumbo, B. Spataro
INFN/LNF, Frascati (Roma)
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We present here a preliminary design, including RF modeling, cooling, and thermal stress and frequency detuning, of an S-band RF gun capable of running near 500 Hz, for application to FEL and inverse Compton scattering sources. The RF design philosophy incorporates many elements in common with the LCLS gun, but the approach to managing cooling and mechanical stress diverges significantly. We examine the new proprietary approach of RadiaBeam Technologies for fabricating copper structures with intricate internal cooling geometries. We find that this approach may enable very high repetition rate, well in excess of the nominal project this design is directed for, the SPARX FEL.
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| TUPPH040 |
A Hybrid Standing Wave-Traveling Wave Photoinjector
|
334 |
| |
- A. Fukasawa, H. Badakov, B. D. O'Shea, J. B. Rosenzweig
UCLA, Los Angeles, California
- D. Alesini, L. Ficcadenti, B. Spataro
INFN/LNF, Frascati (Roma)
- L. Palumbo
Rome University La Sapienza, Roma
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We present here the RF aspects and beam dynamics study of a hybrid photoinjector, where the cathode section is standing wave, and the section downstream of the third (coupling) cell is traveling wave. This device has strong RF advantages: there is a single feed, mitigating expense, and there is a nearly complete suppression of reflected power during the SW section fill. This, critically, allows one to scale these devices to higher field and frequency, which should dramatically improve beam brightness. Further, the beam dynamics are fundamentally changed, as the TW section acts as a velocity buncher. Thus one may produce low emittance, >kA beams at 20-30 MeV from such a device. We discuss here results of detailed beam dynamics simulations, RF design and initial cold-testing, and preparations for high power testing.
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