IIT, Chicago, Illinois
Illinois Institute of Technology, Chicago, Illinois
Fermilab, Batavia
Muons, Inc, Batavia
Funding: Supported in part by USDOE Contract DE-FG02-6ER86281
The study of Muon beam optics is crucial for future Neutrino Factory and Muon Collider facilities. At present, the GEANT4-based simulation tools for Muon beam tracking such as G4beamline and G4MICE are based on single particle tracking without collective effects taken into account. However, it is known that collective effects such as space charge and wakefields for muons (in matters or vacuum) are not ignorable. As the first step, space charge computation has been implemented into muon tracking. The basic algorithm is particle to particle interactions through retarded electro-magnetic fields. The momentum impulse by collective effects is imposed on every particle at each collective step, and the G4beamline main code is used for tracking. Comparisons to LANL Parmela are illustrated and analyzed. Optimizations of the algorithm are also underway to gain less computing time and more accuracy. Moreover, the idea of enhancing ionization cooling efficiency by utilizing the collective effect due to polarized charges in matter appears to be possible, and the preliminary estimation has been done.
SLAC, Menlo Park, California
Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515.
Gravitational instability of a star distribution in a galaxy is a well-known phenomenon in astrophysics. This problem can be analyzed using the standard tools developed in accelerator physics for analyzing the onset of beam instability and loss of Landau damping. An attempt is made here for a nonrotating galaxy. Predictions for the maximum stable galaxy size are in remarkable agreement with observations.
CERN, Geneva
EPFL, Lausanne
The CERN PS crosses transition energy at about 6 GeV by using a second order gamma jump performed with special quadrupoles. However, for high-intensity beams, and in particular the single bunch beam for the neutron Time-of-Flight facility, a controlled longitudinal emittance blow-up is still needed to prevent a fast single-bunch vertical instability from developing near transition. A series of studies have been done in the PS in 2008 to measure the beam behaviour near transition energy for different settings of the gamma transition jump. The purpose of this paper is to compare those measurements with simulations results from the HEADTAIL code, which should allow to understand better the different mechanisms involved and maybe improve the transition crossing.