Fermilab, Batavia, USA
Muon Collider (MC) is a promising candidate for the next energy frontier machine. However, in order to obtain peak luminosity in the 1034cm-2s-1 range the collider lattice design must satisfy a number of stringent requirements. In particular the expected large momentum spread of the muon beam and the very small β* call for a careful correction of the chromatic effects. Here we present a particular solution for the interaction region (IR) optics whose distinctive feature is a three-sextupole local chromatic correction scheme. The scheme may be applied to other future machines where chromatic effects are expected to be large.
Fermilab, Batavia, USA
One of the key systems of a Muon Collider (MC)- seen as the most exciting options for the energy frontier machine in the post-LHC era - is its interaction region (IR). Designs of its optics, magnets and machine-detector interface are strongly interlaced and iterative. As a result of recent comprehensive studies, consistent solutions for the 1.5 TeV c.o.m. MC IR have been found and are described here. To provide the required momentum acceptance, dynamic aperture and chromaticity, innovative approach was used for the IR optics. Conceptual designs of large-aperture high-field dipole and high-gradient quadrupole magnets based on Nb3Sn superconductor were developed and analyzed in terms of the operation margin, field quality, mechanics, coil cooling and quench protection. Shadow masks in the interconnect regions and liners inside the magnets are used to mitigate unprecedented dynamic heat deposition due to muon decays (~1 kW/m). It is shown that an appropriately designed machine-detector interface with sophisticated shielding in the detector has a potential to substantially suppress the background rates in the MC detector.
Fermilab, Batavia, USA
Requirements and operating conditions for a Muon Collider Ring (MCR) pose significant challenges to superconducting magnets. The dipole magnets should provide a high magnetic field to reduce the ring circumference and thus maximize the number of muon collisions during their lifetime. One third of the beam energy is continuously deposited along the lattice by the decay electrons at the rate of 0.5 kW/m for a 1.5-TeV c.o.m. MCR. Unlike dipoles in proton machines, the MCR dipoles should allow this dynamic heat load to escape the magnet helium volume in horizontal plane predominantly towards the ring center. Two alternative designs, one based on the open mid-plane approach with block type coils and absorber outside the coils, and another based on the traditional large-aperture cos-theta approach with a shifted beam pipe and absorber inside the coil aperture were developed for the MCR designed for a luminosity of 1034 cm-2s−1. This paper presents the analysis and comparison of radiation effects in MCR based on the two dipole magnets. Tungsten masks in the interconnect regions are used in both cases to mitigate the unprecedented dynamic heat deposition and radiation in the magnet coils.
Muons, Inc, Batavia, USA
Northern Illinois University, DeKalb, Illinois, USA
Lewis University, Romeoville, Illinois, USA
Technological innovations in recent years have revived interest in muon colliders as the next generation energy frontier machine. The biggest challenge for muon colliders is that muons decay. Advances in muon cooling technology will make the focussing and acceleration of muons to TeV energies possible. The challenge for the detectors in such machines is overcoming the large backgrounds from muon decays in the colliding ring lattice that will inundate the interaction region (IR) and will make triggering and data reconstruction a challenge. Developing simulation tools that can reliably model the environment of the muon collider IR will be critical to physics analyses. We will need to expand the capabilities of current programs and use them to benchmark and verify results against each other. Here we are comparing an emerging capabiligy of G4beamline, an interface for physicists to GEANT4 code, with MARS, a mature program for particle fluences, in developing code for muon collider background studies
Muons, Inc, Batavia, USA
Northern Illinois University, DeKalb, Illinois, USA
Lewis University, Romeoville, Illinois, USA
Muon colliders are considered to be an important future energy frontier accelerator. It is possible to build a large muon collider as a circular machine, even at multi-TeV energies, due to the greatly reduced synchrotron radiation expected from muons. In addition to the same physics processes present in an electron collider, a muon collider will have the potential to produce s-channel resonances such as the various Higgs states at an enhanced rate. For a muon collider with 750 GeV/c mu+ and mu- with 1012 mu per bunch we would expect 4.3x105 muon decays per meter. These muon decays will produce very energetic off momentum electrons that can produce detector backgrounds that can affect the physics. These backgrounds include electrons from muon decays, synchrotron radiation from the decay electrons, hadrons produced by photo-nuclear interactions, coherent and incoherent beam-beam pair production and Bethe-Heitler muon production. In this paper we will discuss these processes and calculate particle fluxes into the detector volume from these background processes.
Northern Illinois University, DeKalb, Illinois, USA
Muons, Inc, Batavia, USA
Lewis University, Romeoville, Illinois, USA