Abstracts Brochure - CERN

WEPLS017
WEPLS018
WEPLS019
28-Jun-06 16:00 - 18:00 WEPLS — Poster Session
regions between the HCC segments may provide a cost effective solution to the high repetition rate needed for an
intense neutrino factory or high average luminosity muon collider. In the gaseous hydrogen absorber case, the
pressurized RF cavities can be operated at low temperature to improve their efficiency for higher repetition rates.
Numerical simulations are used to optimize and compare the liquid and gaseous HCC techniques.
International Scoping Study (ISS) of a Future Accelerator Neutrino Complex
The ISS, launched at NuFact05 to evaluate the
M.S. Zisman (LBNL)
physics case for a facility, along with options
for the accelerator complex and detectors, is
laying the foundations for a subsequent conceptual-design study. It is hosted by RAL and organized by the international
community, with participants from Europe, Japan, and the U.S. Here we cover work of the Accelerator Group.
For the 4 MW proton driver, we consider linacs, synchrotrons, and FFAG rings. For targets, issues of both liquidmetal
and solid materials are examined. For beam conditioning (phase rotation, bunching, and ionization cooling),
we evaluate schemes with and without cooling, the latter based on scaling FFAG rings. For acceleration, we examine
scaling FFAGs and hybrid systems comprising linacs, dogbone RLAs, and non-scaling FFAGs. For the decay ring we
consider racetrack and triangular shapes, the latter capable of simultaneously illuminating two different detectors at
different baselines. Comparisons are made between various technical approaches to identify optimum design choices
for the facility.
Optics for Parametric-resonance Ionization Cooling of Muon Beams
The realization of a muon collider requires a
R.P. Johnson (Muons, Inc) Y.S. Derbenev (Jefferson Lab)
reduction of the 6D normalized emittance of
an initially generated muon beam by a factor
of more than 10 6 . Analytical and simulation studies of 6D muon beam ionization cooling in a helical channel filled
with pressurized gas or liquid hydrogen absorber indicate that a factor of 10 6 is possible. Further reduction of
the normalized 4D transverse emittance by an additional two orders of magnitude is envisioned using Parametricresonance
Ionization Cooling (PIC). To realize the phase shrinkage effect in the parametric resonance method, one
needs to design a focusing channel free of chromatic and spherical aberrations. We report results of our study of a
concept of an aberration-free wiggler transport line with an alternating dispersion function. Resonant beam focusing
at thin beryllium wedge absorber plates positioned near zero dispersion points then provides the predicted PIC effect.
Optics and RF Parameters for Absorber-based Reverse Emittance Exchange of Muon
Beams
The normalized longitudinal emittance of a
R.P. Johnson (Muons, Inc) Y.S. Derbenev (Jefferson Lab)
muon beam after six-dimensional ionization
cooling appears very small compared to the
value that could be utilized or maintained after acceleration to muon collider energy. This circumstance offers the
possibility for further reduction of the transverse emittance by introducing absorber-based reverse emittance exchange
(REMEX) between longitudinal and transverse degrees of freedom before acceleration to high energy. REMEX follows
Parametric-resonance Ionization Cooling and is accomplished in two stages. In the first stage the beam is stretched
to fill the RF bucket at the initial cooling energy. In the second stage the beam is accelerated to about 2.5 GeV, where
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