Abstracts Brochure - CERN

THPCH — Poster Session 29-Jun-06 16:00 - 18:00
High-quality Proton Beam Obtained by Combination of Phase Rotation and the Irradiation
of the Intense Short-pulse Laser
Ion production from laser-induced plasma
has been paid attention because of its high acceleration
gradient (>100GeV/m) compared
with conventional RF accelerator. Its energy
spectrum is Maxwell-Boltzmann distribution
with high-energy cut-off, which limited its
application. The phase rotation scheme,
which rotates laser produced ions by an RF
electric field synchronous to the pulse laser
S. Nakamura, Y. Iwashita, A. Noda, T. Shirai, H. Souda, H. Tongu
(Kyoto ICR) S. Bulanov, T. Esirkepov, Y. Hayashi, M. Kado, T.
Kimura, M. Mori, A. Nagashima, M. Nishiuchi, K. Ogura, S. Orimo,
A. Pirozhkov, A. Sagisaka, A. Yogo (JAEA) H. Daido (New Affiliation
Request Pending) A. Fukumi (Okayama University, Faculty
of Science) Z. Li (NIRS) A. Ogata, Y. Wada (HU/AdSM) T. Tajima
(JAEA/FEL) T. Takeuchi (AEC)
in the longitudinal phase space, was applied to proton beam up to 0.9MeV emitted from Ti foil with 3mm thickness
irradiated by focused laser-pulse with peak intensity of 9 ´ 1017W/cm2. Multi-peaks with ∼6% width (FWHM) were
created and intensity multiplication up to 5 was attained around 0.6MeV region. The proton production process by
the intense short-pulse laser has been optimized with use of time of flight measurement of proton beam detected by a
plastic scintillation counter, which is specially shielded from the heavy background of electrons and X-rays induced
by the intense laser. We have succeeded in on-line measurement of such a proton signal by the detector for the first
time, which played an essential role for the investigation of phase rotation scheme.
SNS Transverse and Longitudinal Laser Profile Monitors Design, Implementation and Results
SNS is using a Nd:YAG laser to measure
transverse profiles at nine-stations in the 186- S. Assadi (ORNL)
1000 MeV Super-Conducting LINAC (SCL)
and a Ti:Sapphire mode-locked laser to measure longitudinal profiles in the 2.5 MeV Medium Energy Beam Transport
(MEBT). The laser beam is scanned across the H − beam to photo-neutralize narrow slices. The liberated electrons
are directly collected to measure the transverse or longitudinal beam profiles. We have successfully measured the
transverse and longitudinal profiles at all stations. The SCL laser system uses an optical transport line that is installed
alongside the 300 meter super-conducting LINAC to deliver laser light at nine locations. Movement of the laser
light in the optical transport system can lead to problems with the profile measurement. We are using telescopes to
minimize the oscillations and active feedback system on mirrors to correct the drifts and movements. In this paper
we present our implementation and beam profiles measured during SCL commissioning. We also discuss future
improvements, drift/vibration cancellation system, as well as plan to automate subsystems for both the transverse
and the longitudinal profiles.
A Phased-locked SESAM Laser Oscillator for the ELSA Photoinjector
A new laser oscillator has been developed for
the ELSA photoinjector. It is a fibered-diode- V. Le Flanchec, P. Balleyguier (CEA)
pumped mode-locked Nd:YVO4 laser, with
a completely passive cooling design. Mode-locking is achieved by a saturable absorber mirror. Such a passive laser
oscillator must be synchronized with the ELSA electron bunches. A phased-locked loop has been developed for
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