Abstracts Brochure - CERN

TUPLS — Poster Session 27-Jun-06 16:00 - 18:00
allowing a wider range of design choices. We adopt the thin-element kick model for a degenerate F0D0 cell composed
of D and F combined function magnets. The dipole field components are parametrised in terms of the bending at the
reference momentum and the reverse bend angle. The split between positive and negative bending sets the shape
of the closed orbits. The cost function, based on stored magnetic energy, is explored in terms of the split. Two cost
minima are found, one corresponding to minimum peak magnet field in the F element, and another to minimum
radial aperture in the D element. Analytic formulae are given for the minimization conditions. The minimum field
lattice is similar to existing designs based on minimizing the path length variation, but the minimum aperture lattice
presents a new direction for future detailed design studies.
Linear-field Nonscaling FFAG with Equal Longitudinal and Transverse Reference Momenta
An unusual feature of linear-field nonscaling
FFAG designs is that the radio-frequency is S.R. Koscielniak (TRIUMF)
not necessarily synchronous with the reference
orbit and momentum chosen for the lattice design. This arises because optics design prefers the reference
geometry to be composed of straight lines and arcs of circles - either at the mean momentum, or at high momentum
to centre the orbit in the F element. The asynchronous acceleration proposed for rapid acceleration has strong
requirements to set the longitudinal reference at 1/4 and 3/4 of the momentum range to minimize phase slip. The
usual particle-tracking programs, such as MAD, though sophisticated in the transverse plane, are far cruder in their
longitudinal working and do not allow for a longitudinal reference momentum and RF phase independent of the
transverse values. In the context of a thin-element lattice model, we show how to make the transverse reference
momentum and optic design coincident with the longitudinal reference by adjusting the ratio of positive and negative
bending in the D and F elements, respectively, and retaining a lines and arcs composition for the reference orbit. This
prepares the way for MAD tracking.
Analytic Formulae for Linear-field Non-scaling FFAG Orbits
Non-scaling FFAG accelerators using constant-gradient
F and D magnets with their S.R. Koscielniak (TRIUMF) M.K. Craddock (UBC & TRIUMF)
fields decreasing outwards can compact ion
orbits for a wide range of momentum (e.g., 1:2) into a narrow radial range. Designs to accelerate protons, ions and
muons are currently being studied for proton drivers, cancer therapy facilities and neutrino factories. In this paper,
analytic formulae are reported for some basic orbit properties, helping to make clear their dependence on the various
design parameters and momentum. For the designs tested so far the numerical results are in excellent agreement
with those obtained using lattice codes.
Conceptual Design of FFAG Systems for High Intensity Accelerators
Intense proton accelerators are under discussion
as spallation neutron sources for the S.A. Martin (FZJ)
production of neutrons in condensed matter
physics, for the Accelerator driven Transmutation (ATW) of radioactive Waste, as well as for the production of
secondary beams like Anti Protons. The pulsed neutron source requires a proton beam with an average power of up
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TUPLS072
TUPLS073
TUPLS074