Abstracts Brochure - CERN

WEPCH — Poster Session 28-Jun-06 16:00 - 18:00
Simulation of Ions Acceleration and Extraction in Cyclotron C400
The Belgian company IBA, together with scientists
of the JINR in Dubna is designing a
superconducting isochronous cyclotron for
therapy by Carbon beams. The new cy-
Y. Jongen, W.J.G.M. Kleeven (IBA) G.A. Karamysheva, S.A. Kostromin,
N.A. Morozov (JINR)
clotron C400 has to deliver carbon ions with energy 400 MeV/amu and protons with energy close to 250 MeV.
The cyclotron has a compact type superconducting magnet, with a pole radius of 187 cm. The axial focusing is
provided by four sectors, with a spiral angle increasing to a maximum value close to 70 o at maximum energy. With
this design, an axial betatron frequency is maintained during most of the acceleration. The beam acceleration is
provided by two spiral dees located in opposite valleys. The dee voltage increases from 100 kV at the center to 200
kV at extraction. The paper presents the analysis of the beam acceleration in the proposed new cyclotron. During
the acceleration, several resonance lines are crossed, but the paper demonstrates that this resonance crossing is done
without damaging the beam properties. Extraction of the Carbon ions is done by an electrostatic deflector, followed
by magnetic correctors. Protons are extracted at lower energy by stripping 2H + 1 ions.
New Vortices in Axisymmetric Beams in Periodic Magnetic Field
We analyzed localized vortices in non-neutral
inhomogeneous by density and velocity Y. Golub (MRTI RAS)
electron beams propagating in vacuum along
the both homogeneous and periodic external magnetic fields. The periodic magnetic field has a spatial period as
in undulator. These vortices distinguish from vortices, which used in */** because of periodic external magnetic
field. Also new types of vortex are obtained by new solution method of nonlinear equations**. The new method is
development of a method described in **.That method distinguish from standard Larichev-Reznik or Reznik method,
which used in *. It has been found new expression for electric field potential of vortex in a wave frame. New vortices
are new solitons in the periodic external magnetic field.
*Golub Yu.Ya. et al. In: Nonlinear world: IV Intern. Workshop on Nonlin. and Turbul. Proc. in Phys., (ed. by
V.G. Bar’yakhtar et al.) World Scientific Publishing Co. Pte. Ltd., Singapore, 1990, vol. 2, p. 857.**Golub Yu.Ya.
Proceedings of EPAC 2002, Paris, France, p.1253.
Non Steady Acceleration in High Current Racetrack Microtron
Racetrack microtron configuration makes it
possible an external injection of the pre V.G. Kurakin (LPI)
bunched electron beam, thus allowing particle
lossless acceleration. This prevents also an intensity auto modulation - the annoying phenomenon that limits
the accelerated current. The next natural limit of accelerator intensity namely the resonator input power limitation
might be overcome for short beam pulses. For non steady regime, stored resonator energy might be used as it often is
used for rf linear accelerator applications. The equations of self consistent beam - cavity interaction are derived in the
paper, higher order cavity modes of the radiation field being taken into account. The results of computer simulation
of intensive beam acceleration in racetrack microtron for non steady case are presented in the form of various plots
and histograms. The possible applications of the racetrack intensive short beam current pulses are discussed.
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