Paper | Title | Page |
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MOP001 | Charge Separation for Muon Collider Cooling | 103 |
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Most schemes for six dimensional muon ionization cooling work for only one sign. It is then necessary to have charge separation prior to that cooling. Schemes of charge separation using bent solenoids are described, and their simulated performances reported. It is found that for efficient separation, it should take place at somewhat higher momenta than commonly used for the cooling. | ||
MOP002 | Tapered Six-Dimensional Cooling Channel for a Muon Collider | 106 |
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A high-luminosity muon collider requires a reduction of the six-dimensional emittance of the captured muon beam by a factor of approximately 106. Most of this cooling takes place in a dispersive channel that simultaneously reduces all six phase space dimensions. We describe a tapered 6D cooling channel that should meet the requirements of a muon collider. The parameters of the channel are given and preliminary simulations are shown of the expected performance. | ||
MOP003 | Six-Dimensional Bunch Merging for Muon Collider Cooling | 109 |
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A muon collider requires single, intense, muon bunches with small emittances in all six dimensions. It is most efficient to initally phase-rotate the muons into many separate bunches, cool these bunches in six dimensions (6D), and, when cool enough, merge them into single bunches (one of each sign). Previous studies only merged in longitudinal phase space (2D). In this paper we describe merging in all six dimensions (6D). The scheme uses rf for longitudinal merging, and kickers and transports with differing lengths (trombones) for transverse merging. Preliminary simulations, including incorporation in 6D cooling, is described. | ||
MOP056 | A Compact and High Performance Muon Capture Channel for Muon Accelerators | 208 |
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Funding: Work is funded by U.S. Dept. of Energy grant numbers DE AC02-98CH10886. It is widely believed that a neutrino factory would deliver unparallel performance in studying neutrino mixing and would provide tremendous sensitivity to new physics in the neutrino sector. Here we will describe and simulate the front-end of the neutrino factory system, which plays critical role in determining the number of muons that can be accepted by the downstream accelerators. In this system, a proton bunch on a target creates secondaries that drift into a capture transport channel. A sequence of rf cavities forms the resulting muon beams into strings of bunches of differing energies, aligns the bunches to nearly equal central energies, and initiates ionization cooling. For this, the muon beams are transported through sections containing high-gradient cavities and strong focusing solenoids. In this paper we present results of optimization and variation studies toward obtaining the maximum number of muons for a neutrino factory by using a compact transport channel. Stratakis et al. Phys. Rev. ST Accel. Beams 14, 011001 (2011). |
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MOP059 | Simulations of the Tapered Guggenheim 6d Cooling Channel for the Muon Collider | 217 |
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Funding: Work is supported by the U.S. Department of Energy. Recent progress in six-dimensional (6D) cooling simulations for the Muon Collider based on the RFOFO ring layout is presented. In order to improve the performance of the cooling channel a tapering scheme is studied that implies changing the parameters such as cell length, magnetic field strength, RF frequency, and the amount of the absorbing material along the cooling channel. This approach allows us to keep the cooling rates high throughout the process. The results of the simulations carried out in G4beamline are presented. |
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TUP177 | Open Midplane Dipoles for a Muon Collider | 1160 |
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Funding: This work is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 and SBIR contract DOE Grant Numbers DE-FG02-07ER84855 and DE-FG02-08ER85037. For a muon collider with copious decay particles in the plane of the storage ring, open-midplane dipoles (OMD) may be preferable to tungsten-shielded cosine-theta dipoles of large aperture. The OMD should have its midplane completely free of material, so as to dodge the radiation from decaying muons. Analysis funded by a Phase I SBIR suggests that a field of 10-20 T should be feasible, with homogeneity of 1x10-4 and energy deposition low enough for conduction cooling to 4.2 K helium. If funded, a Phase II SBIR would refine the analysis and build and test a proof-of-principle magnet. |
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WEOCS3 |
HTS Magnets for Accelerator and Other Applications | |
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Funding: This work is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886. High Temperature Superconductors (HTS) are now becoming a crucial part of future medium and high field magnet applications in several areas including accelerators, energy storage, medical and user facilities. A second generation HTS quadrupole is being constructed for the Facilities for Rare Isotope Beams (FRIB). The muon collider requires high field solenoids in the range of 40-50 T - an R&D that is partly supported by SBIRs and partly programs at various laboratories. Superconducting Magnetic Energy Storage (SMES) R&D, recently funded by ARPA-E, requires large aperture HTS solenoid in the range of 25-30 T. A user facility at National High Magnetic Field Laboratory (NHMFL) has been funded to develop a 32 T solenoid. All of these programs require HTS in a quantity never obtained before for magnet applications and would play a key role in developing HTS for magnet applications. High field magnets pose special challenges in terms of quench protection, large stored energy and large stresses, etc. This presentation will review various ongoing activities, and examine the future prospects of HTS magnets in a number of applications, with a particular emphasis on high field applications. |
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Slides WEOCS3 [2.761 MB] | |
THOAS4 | Enhancement of RF Breakdown Threshold of Microwave Cavities by Magnetic Insulation | 2053 |
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Funding: This work is funded by US Dept. of Energy grant number DE AC02-98CH10886. Limitations on the maximum achievable accelerating gradient of microwave cavities can influence the performance, length, and cost of particle accelerators. Gradient limitations are widely believed to be initiated by electron emission from the cavity surfaces. Here, we show that field emission is effectively suppressed by applying a tangential magnetic field to the cavity walls, so higher gradients can be achieved. Numerical simulations indicate that the magnetic field prevents electrons leaving these surfaces and subsequently picking up energy from the electric field. Implementation of the proposed concept into prospective particle accelerator applications is studied by two specific examples - a multi TeV lepton-antilepton collider and a linear muon accelerator driver for an intense neutrino source. |
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Slides THOAS4 [1.441 MB] | |
THOBN2 | Muon Collider Final Cooling in 30-50 T Solenoids | 2061 |
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Muon ionization cooling to the required transverse emittance of 25 microns can be achieved with liquid hydrogen in high field solenoids, provided that the momenta are low enough. At low momenta, the longitudinal emittance rises because of the negative slope of energy loss versus energy. Assuming initial emittances that have been achieved in six dimensional cooling simulations, optimized designs are given using solenoid fields limited to 30, 40, and 50 T. The required final emittances are achieved for the two higher field cases. | ||
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Slides THOBN2 [0.319 MB] | |