Abstracts Brochure - CERN

TUPLS — Poster Session 27-Jun-06 16:00 - 18:00
amplitudes) are also given. We show that the system is not correct in the second and last but one equations for the
case of half cell termination and non zero second order coupling constants. Due to the relevance of this formulation
and of the case treated, we pay a particular attention to find the missing terms in the above mentioned equation. We
suggest a correction term, having in addition a deep meaning from electromagnetic point of view. By means of this
term we may justify the analytical solution given by the authors. Some numerical examples are also given showing
that a discrepancy appears comparing the new equations with the results of the non-correct formulation.
Optimization Design of a Side Coupled Linac (SCL) for Protontherapy: a New Feeding
Solution
It is proposed to use an SCL, starting at
30MeV, up to 230MeV. The linac consists of
25 modules (two tanks each). Twelve, 3GHz
power generators, feed two modules in parallel,
with the last power generator feeding the
last module. The SCL is designed, assuming
V.G. Vaccaro, A. D’Elia (Naples University Federico II and INFN)
T. Clauser, A.C. Rainò (Bari University, Science Faculty) C. De Martinis,
D. Giove, M. Mauri (INFN/LASA) S. Lanzone (CERN) M.R.
Masullo (INFN-Napoli) V. Variale (INFN-Bari)
a mean accelerating field in the cavities of 16,5MV/m. The longitudinal and transverse beam dynamics has been
studied, assuming that the input parameters (emittance, energy spread and mean current) are those of commercial
30MeV cyclotrons. The characteristics of the ejected beam were analysed: the transmittance value is largely sufficient
to deliver a correct dose for therapy; the beam line activation is kept largely below allowed levels; the output energy
spread is sufficiently small. The first prototype module is under construction and a second one is under design.
Contacts with e2v have been established for defining an agreement, which proposes to use magnetrons as feeders for
the acceleration tests. Attention was therefore paid to phase locking constraints between feeders. Theoretical studies
suggest that transmittance stays constant if de-phasing is kept into values that seem attainable with magnetrons.
A Rationale to Design Side Coupled Linac (SCL): a Faster and More Reliable Tool
A module of an SCL is formed by a cascade
of two or more tanks, connected by a Bridge
Couplers (BC) with an RF feeder, which realizes
a well defined accelerating field con-
V.G. Vaccaro, A. D’Elia (Naples University Federico II and INFN)
M.R. Masullo (INFN-Napoli)
figuration in all the coupled cavities. Even resorting to geometrical scaling for the design of the adjacent tanks in
the module it is not possible to reproduce the same e-m parameters. In addition to this the BC’s for each tanks
have a different geometrical design because of phasing constraints. The standard procedure may leads a very slow
convergence of the design to the optimum and it is not in general clear if the optimum is reached. In this paper a
rationale for designing a module of an SCL will be described and it will be presented its application to PALME first
module (30-3???MeV). From a lumped circuit model one may get useful relations between e-m global response of the
system and single cell parameters. Therefore it provides a certain number of tools which are used for the designing
steps in connection with the standard electromagnetic CAD’s, the results of which were used as "measurements".
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TUPLS048
TUPLS049