Fermilab, Batavia, Illinois, USA
A preliminary design of the 125-GeV Higgs Factory (HF) Muon Collider (MC) has identified an enormous background loads on the HF detector. This is related to the twelve times higher muon decay probability at HF compared to that previously studied for the 1.5-TeV MC. As a result of MARS15 optimization studies, it is shown that with a carefully designed protection system in the interaction region, in the machine-detector interface and inside the detector one can reduce the background rates to a manageable level similar to that achieved for the optimized 1.5-TeV case. The main characteristics of the HF detector background are presented for the configuration found.
Fermilab, Batavia, Illinois, USA
Recent discovery of a Higgs boson boosted interest in a low-energy medium-luminosity Muon Collider as a Higgs Factory (HF). A preliminary design of the HF storage ring (SR) is based on cos-theta Nb3Sn superconducting (SC) magnets with the coil inner diameter ranging from 50 cm in the interaction region to 16 cm in the arc. The coil cross-sections were chosen based on the operation margin, field quality and quench protection considerations to provide an adequate space for the beam pipe, helium channel and inner absorber (liner). With the 62.5-GeV muon energy and 2×1012 muons per bunch, the electrons from muon decays deposit about 300 kW in the SC magnets, or unprecedented 1 kW/m dynamic heat load, which corresponds to a multi-MW room temperature equivalent. Based on the detailed MARS15 model built and intense simulations, a sophisticated protection system was designed for the entire SR to bring the peak power density in the SC coils safely below the quench limit and reduce the dynamic heat load to the cold mass by a factor of 100. The system consists of tight tungsten masks in the magnet interconnect regions and elliptical tungsten liners optimized for each magnet.
Muons, Inc, Illinois, USA
Fermilab, Batavia, Illinois, USA
A helical cooling channel (HCC) consisting of a pressurized gas absorber imbedded in a magnetic channel that provides solenoid, helical dipole and helical quadrupole fields has been shown to provide six-dimensional phase space reduction for muon beams. Such a channel can be implemented by a helical solenoid (HS) composed of short solenoid coils arranged in a helical pattern. The magnetic channel will provide the desired Bphi, Bz, and dBphi/dr along the reference path. The channel must allow enough space for RF cavities which replace energy lost in the absorber material present for the cooling process. The study will describe how to achieve the desired field while allowing sufficient space for the cavities. The limits to this design imposed by the achievable current density in the coils will be discussed.
University of Glasgow, Glasgow, United Kingdom
INFN-Napoli, Napoli, Italy
The International Muon Ionization Cooling Experiment is progressing towards a full demonstration of the feasibility of ionization cooling technology decisive for neutrino physics and muon colliders. Step IV should provide the first precise measurements of emittances and first evidence of cooling. The components required for Step IV, including spectrometer solenoids, muon trackers and absorber-FC (focus coil) modules have been assembled with data collection expected in 2015. The physics programme of this Step will be described in detail, with LiH and a few other promising absorber materials of different shapes.
Abstract presented by the chair of the speaker bureau of the MICE collaboration, that would next select a MICE member to prepare and present the poster
IIT, Chicago, Illinois, USA
Sheffield University, Sheffield, United Kingdom
The International Muon Ionization Cooling Experiment will provide the demonstration ionization cooling. The experiment is being built in a series of Steps. Step IV, which consists of a tracking spectrometer upstream and downstream of an absorber/focus-coil (AFC) module will be completed in early in 2015. In this configuration, the emittance of the muon beam upstream and downstream of the absorber will be measured precisely allowing the emittance reduction and the factors that determine the ionization cooling effect to be studied in detail. The AFC module is a 22 liter volume of liquid hydrogen placed inside a superconducting focusing coil. The properties of lithium hydride, and possibly other absorber materials, will also be studied. All the components of Step IV have been manufactured and integration of the experiment in the MICE Hall at the Rutherford Appleton Laboratory is underway. A full study of ionization cooling will be carried out with Step V, which will include a short 201 MHz linac module in which beam transport is achieved with a superconducting “coupling coil”. The status of the preparation of the components of Step V of the experiment will be described briefly.
Fermilab, Batavia, Illinois, USA
A directed R&D program is presently underway in the U.S. to evaluate the designs and technologies required to provide muon-based high energy physics (HEP) accelerator capabilities. Such capabilities have the potential to provide unique physics reach for the HEP community. An overview of the status of the designs for the neutrino factory and muon collider applications is provided. Recent progress in the technology R&D program is summarized.
Fermilab, Batavia, Illinois, USA
Fermilab, Batavia, Illinois, USA
Muons, Inc, Illinois, USA
Fermilab, Batavia, Illinois, USA
JLab, Newport News, Virginia, USA
Muon colliders could provide the most sensitive measurement of the Higgs mass and return the US back to the Energy Frontier. Central to the capabilities of such muon colliders are the cooling channels that provide the extraordinary reduction in emittance required for the precise Higgs mass measurement and increased luminosity for enhanced discovery potential of an Energy Frontier Machine. We present the status of the design and simulation of a complete muon cooling channel that is based on the Helical Cooling Channel (HCC), which operates via continuous emittance exchange to enable the most efficient design.
MuPlus, Inc., Newport News, Virginia, USA
Fermilab, Batavia, Illinois, USA
Muons, Inc, Illinois, USA
JLab, Newport News, Virginia, USA
Muon colliders could provide the most sensitive measurement of the Higgs mass and return the US back to the Energy Frontier. Central to the capabilities of muon colliders are the cooling channels that provide the extraordinary reduction in emittance required for the precise Higgs mass measurement and increased luminosity for enhanced discovery potential of an Energy Frontier Machine. The Helical Cooling Channel (HCC) is able to achieve such emittance reduction and matching sections within the HCC have been successfully designed in the past with lossless transmission and no emittance growth. However, matching into the HCC from a straight solenoid poses a challenge, since a large emittance beam must cross transition. We elucidate on the challenge and present evaluations of two solutions, along with concepts to integrate the operations of a Charge Separator and match into the HCC.
BNL, Upton, Long Island, New York, USA
BNL, Upton, Long Island, New York, USA
We describe a complete 6D rectilinear cooling scheme for use in a Muon Collider. This scheme uses separate 6D cooling channels for the two signs of particle charge. In each, a channel first reduces the emittance of a train of 21 muon bunches until it becomes possible to merge them into a single bunch, one of each sign. The single bunches are then sent through a second rectilinear channel for further cooling towards the requirements of a Muon Collider. We adopt this approach for a new cooling lattice design for the Muon Collider, and for the first time present a end-to-end simulation. We review key parameters such as the required focusing fields, absorber lengths, cavity frequencies and rf gradients.
*D. Stratakis et al., Phys. Rev. ST AB 16, 091001 (2013).
BNL, Upton, Long Island, New York, USA
Fermilab, Batavia, Illinois, USA
Reduction of the 6-dimensional phase-space of a muon beam by 6 orders of magnitude is a key requirement for a Muon Collider. Recently, a 12-stage rectilinear ionization cooling channel has been proposed to achieve that goal. In this paper, we establish the mathematical framework to predict and evaluate the cooling performance of the proposed channel. We predict the system effectiveness, by deriving key lattice parameters such as the lattice quality factor which describes the rate of cooling versus the surviving particles and the longitudinal and effective partition numbers for each stage. Main theoretical findings, such as the equilibrium emittances and effective cooling length, are compared against findings from numerical simulations.
BNL, Upton, Long Island, New York, USA
Fermilab, Batavia, Illinois, USA
Illinois Institute of Technology, Chicago, Illinois, USA
In Muon Accelerators muons are produced by impacting high energy protons onto a target to produce pions. The pions decay to muons which are then accelerated. Through this process a significant background of protons and electrons are generated, which may result in heat deposition on superconducting materials and activation of the machine. In this paper we propose a two-step particle selection scheme: a chicane to remove the high momentum particles from the beam and a Beryllium block absorber that reduces momentum of all particles in the beam, resulting in the loss of low momentum protons. We review the design and numerically examine its impact on the performance of the muon front-end.
SLAC, Menlo Park, California, USA
Fermilab, Batavia, Illinois, USA
JLab, Newport News, Virginia, USA
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
Illinois Institute of Technology, Chicago, Illinois, USA
BNL, Upton, Long Island, New York, USA
LBNL, Berkeley, California, USA
Muon-based facilities offer unique potential to provide capabilities at both the Intensity Frontier with Neutrino Factories and the Energy Frontier with Muon Colliders. They rely on a novel technology with challenging parameters, for which the feasibility is currently being evaluated by the Muon Accelerator Program (MAP). A realistic scenario for a complementary series of staged facilities with increasing complexity and significant physics potential at each stage has been developed. It takes advantage of and leverages the capabilities already planned for Fermilab, especially the strategy for long-term improvement of the accelerator complex being initiated with the Proton Improvement Plan (PIP-II) and the Long Baseline Neutrino Facility (LBNF). Each stage is designed to provide an R&D platform to validate the technologies required for subsequent stages. The rationale and sequence of the staging process and the critical issues to be addressed at each stage, are presented.
