Abstracts Brochure - CERN

MOPCH030
MOPCH031
MOPCH033
26-Jun-06 16:00 - 18:00 MOPCH — Poster Session
exotic undulator designs. We also present studies on solenoid field defects, beam based alignments, exotic electron
bunch production (blow-out of short laser pulses or intensity modulated laser pulses). The possible use of segmented
superconducting micro-undulators will be discussed too.
Production of Coherent X-rays with a Free Electron Laser Based on an Optical Wiggler
V. Petrillo, C. Maroli (Universita’ degli Studi di Milano) A. Bacci,
L. Serafini (INFN-Milano) A. Colzato (Università degli Studi di Milano)
M. Ferrario (INFN/LNF)
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The interaction between high-brightness
electron beams and counter-propagating
laser pulses produces X rays via Thomson
scattering. If the laser source is long enough,
the electrons bunch on the scale of the emit-
ted X-ray wavelength and a regime of collective effects establishes. In this case, the FEL instability develops and
the system behaves like a FEL based on an optical undulator. Coherent X-rays are irradiated, with a bandwidth
thinner than that of the incoherent emission. The emittance of the beam and gradients or irregularities in the laser
energy distribution are the principal factors that limit the growth of the X-ray signal. We analyse with a 3-D code the
transverse effects in the emission produced by a relativistic electron beam when it is under the action of an optical
laser pulse and the X-ray spectra obtained. The scalings typical of the optical wiggler, with very short gain lengths and
overall time durations of the process make possible considerable emission also in violation of the Pellegrini criterion
for static wigglers. A generalized form of this criterion is validated on the basis of the numerical evidence.
Progress on the Pi-mode X-band RF Cavity for SPARC
A. Mostacci, M.E. Esposito, L. Ficcadenti, L. Palumbo (Rome University
La Sapienza) D. Alesini, B. Spataro (INFN/LNF) A. Bacci
(INFN-Milano)
The Frascati photo-injector SPARC (Pulsed
Self Amplified Coherent Radiation Source)
will be equipped with an x-band RF cavity
for linearizing emittance to enhance bunch
compression and for reducing bunch longi-
tudinal energy spread. The nine cell standing wave cavity prototype made of separated cells has been already built
and measured*. In this paper we report on characterization of the first brazed prototype. Heat load studies have been
performed as well to design the cooling system for the final device.
*D. Alesini et al. Nucl. Instr. and Meth. A 554 (2005) 1.
The Overview of PAL-XFEL Design
T.-Y. Lee, Y.S. Bae, J. Choi, J.Y. Huang, H.-S. Kang, M. Kim, I.S. Ko,
D. H. Kuk, J.-S. Oh, Y.W. Parc, J.H. Park, S.J. Park (PAL)
PAL-XFEL is the 4th generation light source
that Pohang Accelerator Laboratory is going
to build. It will use linac based Self Amplified
Spontaneous Emission (SASE) scheme. For
the purpose the linear accelerator, which is now used for the injection to the PLS storage ring, will be upgraded and
expanded to 3.7 GeV. It will have three beamlines of soft X-ray and hard X-ray whose wavelength will reach up to 1
angstrom. In this paper, the overview of PAL-XFEL design will be presented.