• S.A. Kahn, H.G. Kirk
  BNL, Upton, Long Island, New York
• D. Cline, A.A. Garren
  UCLA, Los Angeles, California
• F.E. Mills
  Fermilab, Batavia, Illinois

A hydrogen gas filled muon cooling ring appears to be a promising approach to reducing the emittance of a muon beam for use in a neutrino factory or a muon collider. A small muon cooling ring is being studied to test the feasibility of cooling by this method. This paper describes the magnet system to circulate the muons. The magnet design is optimized to produce a large dynamic aperture to contain the muon beam with minimum losses. Muons are tracked through the field to verify the design.

• J.C. Gallardo, J.S. Berg, R.C. Fernow, H.G. Kirk, R. Palmer
  BNL, Upton, Long Island, New York
• D.V. Neuffer
  Fermilab, Batavia, Illinois
• K. Paul
  Muons, Inc, Batavia

As part of the APS Joint Study on the Future of Neutrino Physics* we have carried out detailed studies of the Neutrino Factory front-end. A major goal of the new study was to achieve equal performance to our earlier feasibility studies** at reduced cost. The optimal channel design is described in this paper. New innovations included an adiabatic buncher for phase rotation and a simplified cooling channel with LiH absorbers. The linear channel is 295 m long and produces 0.17 muons per proton on target into the assumed accelerator transverse acceptance of 30 mm and longitudinal acceptance of 150 mm.

*APS Multi-Divisional Study of the Physics of Neutrinos, http://www.aps.org/neutrino/. **S.Ozaki, R.B.Palmer, M.Zisman and J.C.Gallardo, edts., Tech. Rep., BNL-52623 (2001), http://www.cap.bnl.gov/mumu/studyii/FS2-report.html.

• H.G. Kirk, S.A. Kahn
  BNL, Upton, Long Island, New York
• D. Cline, A.A. Garren
  UCLA, Los Angeles, California
• F.E. Mills
  Fermilab, Batavia, Illinois

We discuss a conceptual design for a compact muon cooling system based on a weak-focusing ring loaded with high-pressure Hydrogen gas. We demonstrate that such a ring will be capable of cooling a circulating muon beam in each of the three spatial dimensions so that 6d cooling of the muon beam phase space is achieved.

• Y. Fukui, D. Cline, A.A. Garren
  UCLA, Los Angeles, California
• H.G. Kirk
  BNL, Upton, Long Island, New York

• H.G. Kirk, H. Ludewig, L.F. Mausner, N. Simos, P. Thieberger
  BNL, Upton, Long Island, New York
• Y. Hayato, K. Yoshimura
  KEK, Ibaraki
• K.T. McDonald
  PU, Princeton, New Jersey
• J. Sheppard
  SLAC, Menlo Park, California
• L.P. Trung
  Stony Brook University, Stony Brook

The long term survivability of materials which can be used either for high-intensity targets or for the environment surrounding the target can be greatly influenced by how the physical properties of the material are altered by radiation damage. We have irradiated several candidate materials and report here on physical properties before and after irradiation.

• S. Bellavia, S.A. Kahn, H.G. Kirk, H. Ludewig, D. Raparia, N. Simos
  BNL, Upton, Long Island, New York

Thermodynamic studies have been performed for the beam target and focusing horn system to be used in a very long baseline neutrino oscillation experiment. A 2mm rms beam spot with power deposition of over 18 KW presents challenging material and engineering solutions to this project. Given that the amount of heat transferred by radiation alone from the target to the horn is quite small, the primary mechanism is heat removal by forced convection in the annular space between the target and the horn. The key elements are the operating temperature of the target, the temperature of the cooling fluid and the heat generation rate in the volume of the target that needs to be removed. These working parameters establish the mass flow rate and velocity of the coolant necessary to remove the generated heat. Several cooling options were explored using a carbon-carbon target and aluminum horn. Detailed analysis, trade studies and simulations were performed for cooling the horn and target with gaseous helium as well as water.

• H.G. Kirk, S.A. Kahn, H. Ludewig, R. Palmer, V. Samulyak, N. Simos, T. Tsang
  BNL, Upton, Long Island, New York
• J.R.J. Bennett
  CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
• T.W. Bradshaw, P. Drumm, T.R. Edgecock, Y. Ivanyushenkov
  CCLRC/RAL, Chilton, Didcot, Oxon
• I. Efthymiopoulos, A. Fabich, H. Haseroth, F. Haug, J. Lettry
  CERN, Geneva
• T.A. Gabriel, V.B. Graves, J.R. Haines, P.T. Spampinato
  ORNL, Oak Ridge, Tennessee
• Y. Hayato, K. Yoshimura
  KEK, Ibaraki
• K.T. McDonald
  PU, Princeton, New Jersey

We describe an experiment designed as a proof-of-principle test for a target system capable of converting a 4 MW proton beam into a high-intensity muon beam suitable for incorporation into either a neutrino factory complex or a muon collider. The target system is based on exposing a free mercury jet to an intense proton beam in the presence of a high strength solenoidal field.

• P.T. Spampinato, T.A. Gabriel, V.B. Graves, M.J. Rennich
  ORNL, Oak Ridge, Tennessee
• A. Fabich, H. Haseroth, J. Lettry
  CERN, Geneva
• H.G. Kirk, N. Simos, T. Tsang
  BNL, Upton, Long Island, New York
• K.T. McDonald
  PU, Princeton, New Jersey
• P. Titus
  MIT/PSFC, Cambridge, Massachusetts

We describe a mercury jet system that is suitable for insertion into the 15cm diameter bore of a high-field solenoid magnet. The device features a hermetically sealed primary containment volume which is enclosed in a secondary containment system to insure isolation of mercury vapors from the remaining experimental environment. The jet diameter is 1-cm while the jet velocity will be up to 20 m/s. Optical diagnostics is incorporated into the target design to allow observation of the dispersal of the mercury as a result of interaction with a 24 GeV proton beam with up to 20 x 1012 ppp.