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| MO6RFP080 | Intense Stopping Muon Beams | 560 |
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The study of rare processes using a beam of muons that stop in a target provides access to new physics at and beyond the reach of energy frontier colliders. The flux of stopping muons is limited by the pion production process and by stochastic processes in the material used to slow down the decay muons. Innovative muon beam collection and cooling techniques are applied to the design of stopping muon beams in order to provide better beams for such experiments. Such intense stopping beams will also support the development of applications such as muon spin resonance and muon-catalyzed fusion. |
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| TU5PFP017 | RF Cavities Loaded with Dielectric for Muon Facilities | 846 |
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Funding: Supported in part by FRA DOE contract number DE-AC02-07CH11359 RF cavities below 800 MHz are large, so alternative cavities at low frequencies are needed. Novel dielectric loaded RF cavities will allow smaller diameter cavities to be designed; changing the frequency of a cavity design would be as simple as changing the dielectric cylinder insert material or inner radius of the dielectric in the cavity. This paper discusses RF cavities loaded with dielectric material that could be used in various ways for muon facilities. The examples given are for 400 and 800 MHz cavities. Our initial motivation was to use dielectric to reduce the radial size of gas-filled cavities in helical cooling channels, but dielectric-loading has potential use in vacuum cavities for suppression of dark current emission. We also studied cavities that can be used for the phase rotation channel in the front end of a muon collider or neutrino factory. |
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| TU5PFP018 | Tunable RF Cavities Using Orthogonally Biased Ferrite | 849 |
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Funding: Supported by STTR Grant DE-FG02-07ER86320 and FRA DOE contract number DE-AC02-07CH11359 Originally conceived as a solution for FFAG applications, a new compact RF cavity design that tunes rapidly over various frequency ranges can be used to upgrade existing machines. The design being developed uses orthogonally biased garnet cores for fast frequency tuning and liquid dielectric to adjust the frequency range and to control the core temperature. We describe measurements of candidate ferrite and dielectric materials. The first use of the new cavity concept will be for improvements to the 8 GeV Fermilab Booster synchrotron. |
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| TU6PFP062 | Preparations for Muon Experiments at Fermilab | 1427 |
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Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The use of existing Fermilab facilities to provide beams for two muon experiments –- the Muon to Electron Conversion Experiment (Mu2e) and the Muon g-2 Experiment –- is under consideration. Plans are being pursued to be able to perform these experiments following the completion of the Tevatron Collider Run II with no impact to the on-going Main Injector neutrino program by using spare Booster cycles to provide 8.9 GeV/c protons on target. Utilizing the beam lines and storage rings used today for antiproton accumulation, beams can be prepared for these experiments with minimal disruption, reconfiguration or expansion of the Fermilab accelerator infrastructure. The proposed operational scenarios and required alterations to the complex are described. |
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| TU6RFP033 | AC Dipole System for Inter-Bunch Beam Extinction in the Mu2e Beam Line | 1611 |
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Funding: Supported under DOE contract DE-AC02-07CH11359. The Mu2e experiment has been proposed at Fermilab to measure the rate for muons to convert to electrons in the field of an atomic nucleus with unprecedented precision. This experiment uses an 8 GeV primary proton beam consisting of short (~100 nsec) bunches, separated by 1.7 μs. It is vital that out-of-bunch beam be suppressed at the level of 10-9 or less. Part of the solution to this problem involves a pair of matched dipoles operating resonantly at half the bunch rate. There will be a collimation channel between them such that beam will only be transmitted when the fields are null. The magnets will be separated by 180 degrees of phase advance such that their effects cancel for all transmitted beam. Magnet optimization considerations will be discussed, as will optical design of the beam line. Simulations of the cleaning efficiency will also be presented. |
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| WE6PFP064 | Achromatic Interaction Point Design | 2649 |
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Designers of high-luminosity energy-frontier muon colliders must provide strong beam focusing in the interaction regions. However, the construction of a strong, aberration-free beam focus is difficult and space consuming, and long straight sections generate an off-site radiation problem due to muon decay neutrinos that interact as they leave the surface of the earth. Without some way to mitigate the neutrino radiation problem, the maximum c.m. energy of a muon collider will be limited to about 3.5 TeV. A new concept for achromatic low beta design is being developed, in which the interaction region telescope and optical correction elements, are installed in the bending arcs. The concept, formulated analytically, combines space economy, a preventative approach to compensation for aberrations, and a reduction of neutrino flux concentration. An analytical theory for the aberration-free, low beta, spatially compact insertion is being developed. |
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| WE6PFP089 | Muon Capture, Phase Rotation, and Precooling in Pressurized RF Cavities | 2712 |
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Funding: Supported in part by USDOE STTR Grant DE-FG02-05ER86252 and FRA DOE contract number DE-AC02-07CH11359 Gas-filled RF cavities can provide high-gradient accelerating fields for muons, and can be used for simultaneous acceleration and cooling of muons. In this paper we explore using these cavities in the front-end of the capture and cooling systems for neutrino factories and muon colliders. We consider using gas-filled RF cavities for the initial front end cooling systems. We also consider using them for simultaneous phase-energy rotation and cooling in a front-end system. We also consider using lower-density RF cavities, where the gas density is primarily for RF breakdown suppression, with less cooling effect. Pressurized RF cavities enable higher gradient rf within magnetic fields than is possible with evacuated cavities, enabling more options in the front-end. The status of designs of the capture, phase rotation, and precooling systems of muon beams in pressurized cavities is described. |
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| WE6PFP090 | MANX, A 6-D Muon Beam Cooling Experiment for RAL | 2715 |
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Funding: Supported in part by USDOE STTR Grant DE-FG02-06ER86282 and by FRA under DOE Contract DE-AC02-07CH11359 MANX is a six-dimensional muon ionization cooling demonstration experiment based on the concept of a helical cooling channel in which a beam of muons loses energy in a continuous helium or hydrogen absorber while passing through a special superconducting magnet called a helical solenoid. The goals of the experiment include tests of the theory of the helical cooling channel and the helical solenoid implementation of it, verification of the simulation programs, and a demonstration of effective six-dimensional cooling of a muon beam. We report the status of the experiment and in particular, the proposal to have MANX follow MICE at the Rutherford-Appleton Laboratory (RAL) as an extension of the MICE experimental program. We describe the economies of such an approach which allow the MICE beam line and much of the MICE apparatus and expertise to be reused. |
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| WE6PFP093 | Reverse Emittance Exchange for Muon Colliders | 2721 |
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Funding: Supported in part by USDOE STTR Grant DE-FG02-05ER86253 Muon collider luminosity depends on the number of muons in the storage ring and on the transverse size of the beams in collision. Six-dimensional cooling schemes now being developed will reduce the longitudinal emittance of a muon beam so that smaller high frequency RF cavities can be used for later stages of cooling and for acceleration. However, the bunch length at collision energy is then shorter than needed to match the interaction region beta function. New ideas to shrink transverse beam dimensions by lengthening each bunch (reverse emittance exchange and bunch coalescing) will help achieve high luminosity in muon colliders with fewer muons. Analytic expressions for the reverse emittance exchange mechanism are derived, including a new resonant method of beam focusing. Correction schemes for the aberrations were explored, and a lattice to implement them was proposed. To mitigate space charge detuning and wake field effects, a scheme was invented to coalesce smaller intensity bunches after they are cooled and accelerated to high energy into intense bunches suitable for a muon collider. |
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| WE6PFP094 | Quasi-Isochronous Muon Capture | 2724 |
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Intense muon beams have many potential applications. However, muons originate from a tertiary process that produces a diffuse swarm. To make useful beams, the swarm must be rapidly collected and cooled before the muons decay. A promising new concept for the collection and cooling of muon beams to increase their intensity and reduce their emittances is investigated: the use of a nearly isochronous helical cooling channel (HCC) to facilitate capture of the muons into a few RF bunches. Such a distribution could be cooled quickly and then coalesced efficiently into a single bunch to optimize the luminosity of a muon collider. An analytical description of the method is presented followed by simulation and optimization studies. Practical design constraints and integration into a collider, neutrino factory or intense beam scenario are discussed and plans for further studies are addressed. |
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| WE6PFP095 | Integrating the MANX 6-D Muon Cooling Experiment with the MICE Spectrometers | 2727 |
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Funding: Supported in part by USDOE STTR Grant DE-FG02-06ER86282 The MANX experiment is to demonstrate the reduction of 6D muon phase space emittance using a continuous liquid absorber to provide ionization cooling in a helical solenoid magnetic channel. The experiment involves the construction of a short two-period long helical cooling channel (HCC) to reduce the muon invariant emittance by a factor of two. The HCC would replace the current cooling section of the MICE experiment now being setup at the Rutherford Appleton Laboratory. The MANX experiment would use the existing MICE spectrometers and muon beam line. This paper shall consider the various approaches to integrate MANX into the RAL hall using the MICE spectrometers. This study shall discuss the matching schemes used to minimize losses and prevent emittance growth between the MICE spectrometers and the MANX HCC. Also the placement of additional detection planes in the matching region and the HCC to improve the resolution will be examined. |