Abstracts Brochure - CERN

WEPLS — Poster Session 28-Jun-06 16:00 - 18:00
R&D Status of the High-intense Monochromatic Low-energy Muon Source: PRISM
PRISM is a project of a future intense lowenergy
muon source, which combines monochromaticity
and high purity. Its aimed intensity
is about 10 11 -10 12 muons per second.
The muon beams will have a low kinetic energy
of 20MeV so that it would be optimized
A. Sato, M. Aoki, Y. Arimoto, I. Itahashi, Y. Kuno, K. Kuriyama,
T. Oki, T. Takayanagi, M. Yoshida (Osaka University) M. Aiba, C.
Ohmori, T. Yokoi, K. Yoshimura (KEK) Y. Iwashita (Kyoto ICR) S.
Machida (CCLRC/RAL/ASTeC) Y. Mori (KURRI)
for the stopped muon experiments such as searching the muon lepton flavor violating processes. PRISM consists of
a pion capture section, a pion/muon transfer section and a phase rotation ssection. An FFAG is used as the phase
rotator to achieve the monochromatic muon beams. This paper will describe design status of these sections as well
as construction status of PRISM-FFAG.
Equivalent Velocity Spectroscopy Based on Femtosecond Electron Beam Accelerator
A new femtosecond pulse radiolysis system,
which is called as "Equivalent Velocity Spec- S. Takemoto, T. Kondoh, J. Yang, Y. Yoshida (ISIR)
troscopy (EVS)" based on a photocathode rf
linear accelerator and a femtosecond laser, is developed in ISIR for the study of primly process and ultrafast electron-induced
reactions for the nanofabrication. In order to achieve a high time resolution on femtosecond scale, a
femtosecond electron beam bunch produced by a photocathode accelerator and a synchronized femtosecond laser
were used. The electron bunch and laser pulse were injected with an angle determined by the refractive index of the
sample. The electron bunch was also rotated with a same angle, resulting in the time resolution degradation due to
the velocity difference between light and the electron in the sample is thus avoided. A jitter compensation technique
with a femtosecond streak camera was used to reduce the time jitter between the electron bunch and laser pulse.
Moreover, in EVS, a technique of double laser pulse injection was used to improve the signal to noise ratio due to the
fluctuation of the laser intensity during the measurement.
Femtosecond Single-bunch Electron Linear Accelerator Based on a Photocathode RF Gun
A femtosecond single-bunch electron linear
accelerator based on a photocathode rf gun J. Yang, T. Kondoh, Y. Yoshida (ISIR)
was developed in Osaka University for the
study of radiation-induced ultrafast physical and chemical reactions. A 32 MeV single electron bunch with a bunch
length of 98 fs in rms was generated successfully in the linear accelerator with a magnet bunch compressor. The
dependences of the bunch length and the transverse emittance on the bunch charge were investigated experimentally
and theoretically. The higher-order effects in the magnetic field were studied and compensated successfully by using
a nonlinear energy-phase correlation in the bunch produced in the linear accelerator. By using the femtosecond
electron bunch, an equivalent velocity spectroscopy with a synchronized femtosecond laser, as a new method with
femtosecond time-resolution, was developed for study of the ultrafast reactions or phenomena on the femtosecond
time scale.
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