• S. A. Kahn, M. Alsharo'a, R. P. Johnson
  Muons, Inc, Batavia
• V. Kashikhin, V. S. Kashikhin, K. Yonehara, A. V. Zlobin
  Fermilab, Batavia, Illinois

A helical cooling channel consisting of a pressurized gas absorber imbedded in a magnetic channel that provides superimposed solenoidal, helical dipole and helical quadrupole fields has shown considerable promise in providing six-dimensional cooling of muon beams. The analysis of this muon cooling technique with both analytic and simulation studies has shown significant reduction of muon phase space. A particular channel that has been simulated is divided into four segments each with progressively stronger fields and smaller apertures to reduce the equilibrium emittance so that more cooling can occur. The fields in the helical channel are sufficiently large that the conductor for segments 1 and 2 can be Nb3Sn and the conductor for segments 3 and 4 may need to be high temperature superconductor. This paper will describe the magnetic specifications for the channel and two conceptual designs on how to implement the magnetic channel.

• S. A. Kahn, M. Alsharo'a, R. P. Johnson, M. Kuchnir
  Muons, Inc, Batavia
• R. C. Gupta, R. B. Palmer, P. Wanderer, E. Willen
  BNL, Upton, Long Island, New York
• D. J. Summers
  UMiss, University, Mississippi

The ability of high temperature superconducting (HTS) conductor to carry high currents at low temperatures makes feasible the development of very high field magnets for uses in accelerators and beam-lines. A specific application of a very high field solenoid is to provide a very small beta region for the final cooling stages for a muon collider. This paper will describe a conceptual design of a 50 Tesla solenoid based on Bi-2223 HTS tape, where the magnet will be operated at 4.2 K to take advantage of the high current carrying capacity at that temperature. A 25 Tesla solenoid has been run using a 5 Tesla Bi-2212 insert. The current carrying capacity of the BSCCO wire has been measured to be 266 Amps/mm2 at 4.2 K at the NHFML. This paper will describe the technical issues associated with building this 50 Tesla magnet. In particular it will address how to mitigate the large Lorentz stresses associated with the high field magnet and how to design the magnet to reduce the compressive end forces.

• V. S. Kashikhin, V. Kashikhin, M. J. Lamm, G. Romanov, K. Yonehara, A. V. Zlobin
  Fermilab, Batavia, Illinois
• R. P. Johnson, S. A. Kahn, T. J. Roberts
  Muons, Inc, Batavia

MANX is a 6-dimensional muon ionization-cooling experiment that has been proposed to Fermilab to demonstrate the use of a Helical Cooling Channel (HCC) for future muon colliders and neutrino factories. The HCC for MANX has solenoidal, helical dipole, and helical quadrupole magnetic components which diminish as the beam loses energy as it slows down in a liquid helium absorber inside the magnets. Two superconducting magnet system designs are described which use quite different approaches to providing the needed fields. Additional magnets that provide emittance matching between the HCC and upstream and downstream spectrometers are also described as are the results of G4Beamline simulations of the beam cooling behaviour of the complete magnet and absorber system.

• K. Yonehara, D. R. Broemmelsiek, M. Hu, A. Jansson, V. D. Shiltsev
  Fermilab, Batavia, Illinois
• R. J. Abrams, M. A.C. Cummings, R. P. Johnson, S. A. Kahn, T. J. Roberts
  Muons, Inc, Batavia

MANX is an experiment to prove that effective six-dimensional (6D) muon beam cooling can be achieved a Helical Cooling Channel (HCC) using ionization-cooling with helical and solenoidal magnets in a novel configuration. The aim is to demonstrate that 6D muon beam cooling is understood well enough to plan intense neutrino factories and high-luminosity muon colliders. The experiment consists of the HCC magnets that envelop a liquid helium energy absorber, upstream and downstream instrumentation to measure the particle or beam parameters before and after cooling, and emittance matching sections between the detectors and the HCC. We describe and compare the experimental configuration for both single particle and beam profile measurement techniques based on G4Beamline simulations.

• A. Hershcovitch, M. Diwan, J. C. Gallardo, B. M. Johnson, H. G. Kirk, W.-T. Weng
  BNL, Upton, Long Island, New York
• E. Garate, A. van Drie
  University of California IIrvine, Irvine, California
• S. A. Kahn
  Muons, Inc, Batavia
• N. Rostoker
  UCI, Irvine, California

Plasma lens concept is examined as an alternative to focusing horns and solenoids for a neutrino beam facility. The concept is based on a combined high-current lens/target configuration. Current is fed at an electrode located downstream from the beginning of the target where pion capturing is needed. Some of the current flows through the target, while the rest is carried by plasma outside the target. A second plasma lens section, with an additional current feed, follows the target. Plasma of this section is immersed in a solenoidal magnetic field to facilitate its current profile shaping to optimize pion capture. Simulation of the second section alone yielded a 10% higher neutrino production than the horn system. Plasma lenses have additional advantages: larger axial currents, high signal purity: minimal neutrino background in anti-neutrino runs. Lens medium consists of plasma, consequently, particle absorption and scattering is negligible. Withstanding high mechanical and thermal stresses is not an issue. Results of capturing and focusing obtained for various plasma lens configurations will be presented.

• R. B. Palmer, J. S. Berg, R. C. Fernow, J. C. Gallardo, H. G. Kirk
  BNL, Upton, Long Island, New York
• Y. Alexahin, D. V. Neuffer
  Fermilab, Batavia, Illinois
• S. A. Kahn
  Muons, Inc, Batavia
• D. J. Summers
  UMiss, University, Mississippi

We propose a complete scheme for cooling a muon beam for a muon collider. We first outline the parameters required for a multi-TeV muon collider. The cooling scheme starts with the front end of the Study 2a proposed Neutrino Factory. This yields bunch trains of both muon signs. Emittance exchange cooling in upward climbing helical lattices then reduces the longitudinal emittance until it becomes possible to combine the trains into single bunches, one of each sign. Further cooling is now possible in emittance exchange cooling rings. Final cooling to the required parameters is achieved in 50 T solenoids that use high temperature superconductor. Preliminary simulations of each element will be presented.