Abstracts Brochure - CERN

TUPLS113
TUPLS114
TUPLS115
27-Jun-06 16:00 - 18:00 TUPLS — Poster Session
Designs of Septum Magnet of 3 GeV RCS at J-PARC
M. Yoshimoto, J. Kamiya, M. Kinsho, T. Takayanagi, O. Takeda, M.
Watanabe (JAEA/J-PARC)
254
GeV RCS (Rapid Cycling Synchrotron) at
J-PARC (Japan Proton Accelerator Research
Complex) consists in many kinds of septum
magnets. There are two septum magnets to
inject the beam into the ring, three septum magnets to extract the beam for the users, and two septum magnets to
dump the beam which can not be exchanged its charge at the first foil. In order to reduce the magnetic leakage field
from the septum magnets at the beam orbit in the ring, the silicon steel sheets are set at the outside of the septum
magnets for the magnetic shields. However sufficient spaces to set the thick magnetic shields are not securable at the
divergent duct areas. Therefore the vacuum chambers are made by the magnetic stainless steel and the leakage fields
in the chambers can be reduced. As results of the 3D field calculations by TOSCA, the magnetic leakage field can be
suppressed to a few Gauss or less.
An Improvement of Matching Circuit of RF Kicker Electrodes
Beam extraction system at accelerator of The
T. Kurita, S. Fukumoto, S.H. Hatori (WERC) S. Ninomiya (KEK) Wakasa Wan Energy Research Center employs
RF knockout technology. Narrow band
RF noise is applied to the transverse kicker electrodes to increase betatron amplitude of the beam. Recently some
improvements of the beam extraction system are introduced: To improve the shape of the spill, a feedback control
of noise amplitude is introduced. The feedback control system works as an attenuator, therefore it is necessary to
enhance the noise amplitude of the kicker electrodes to obtain agreeable effect on the spill shape. In order to obtain a
higher voltage, we revamp the matching circuit at the electrodes. By introducing the resonating characteristic at the
matching circuit, we obtained 3 times more amplitude at the electrodes. General shape of the spill is improved by
this work, and extraction efficiency at a real operating condition is also improved.
Transverse Phase Space Painting for the BSNS Injection
The BSNS accelerators consist of an 80MeV
J. Qiu, J. Tang, S. Wang (IHEP Beijing) J. Wei (BNL)
proton Linac and a 1.6GeV rapid cycling
synchrotron (RCS). The ring accumulates
1.88*10 13 protons via multi-turn charge-exchange injection in the phase BSNS-I. The injected beam is painted into
the large transverse phase space to alleviate space-charge effects. The uniformity of beam emittance is important
in reducing the tune shift/spread due to space charge effect. The paper introduces two parameters to evaluate the
uniformity of a distribution. To satisfy BSNS’s low-loss design criteria, extensive comparison has been made to select
injection scenarios using the simulation code ORBIT. This includes painting schemes, the effect of lattice tune, the
injection peak current, and also the impact of chopping injection.