• A. Sato
  Osaka University, Osaka

FFAG lattices with racetrack-shape has been studied to cool muon beams. The ring has straight sections with FFAG magnets, which makes enough space to install kicker magnets to inject and extract the muon beam. Wedge absorbers using superfluid helium and RF cavities are installed to the ring. This paper reports progress of the study.

• A. Sato
  Osaka University, Osaka

The COMET is an experiment to search for the process of muon to electron conversion in a muonic atom, and is in its design phase to be carried out at J-PARC in near future. The experiment uses a long superconducting solenoid channels from a pion production target to a detector system. In order, to study the solenoid channel the g4beamline is used for the magnetic field calculation and beam tracking. This paper reports the status of the simulation studies.

• M.Y. Yoshida, M. Aoki, Y. Kuno, A. Sato
  Osaka University, Osaka
• T. Nakamoto, T. Ogitsu, K. Tanaka, A. Yamamoto
  KEK, Ibaraki

An intense muon beam is mandatory for the next-generation experiments to search for lepton flavor violating processes in the muon sector. The COMET experiment, J-PARC ·10²¹, aims to search for muon to electron conversion with an unprecedented sensitivity.. The muon beam is produced from pion decays in a strong magnetic field generated by superconducting solenoid coils. The large-bore superconducting coils enclose the pion-production target to capture pions with a large solid angle. The magnetic field is designed to have a peak of 5T at the target. To avoid severe radiation from the target, thick shielding is inserted in the warm bore of the pion capture solenoid magnet. The proton beam is injected through the gap between the pion capture solenoid and the subsequent transport solenoid magnets. For this purpose, the bore of the pion capture solenoid has to be larger than 1 m. This paper describes the design of the pion capture solenoid magnet for the COMET experiment.

• J. Pasternak, L.J. Jenner, Y. Uchida
  Imperial College of Science and Technology, Department of Physics, London
• R.J. Barlow
  UMAN, Manchester
• K.M. Hock, B.D. Muratori
  Cockcroft Institute, Warrington, Cheshire
• D.J. Kelliher, S. Machida, C.R. Prior
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• Y. Kuno, A. Sato
  Osaka University, Osaka
• A. Kurup
  Fermilab, Batavia
• J.-B. Lagrange, Y. Mori
  KURRI, Osaka
• M. Lancaster
  UCL, London
• S.A. Martin
  FZJ, Jülich
• C. Ohmori
  KEK/JAEA, Ibaraki-Ken
• J. Pasternak
  STFC/RAL, Chilton, Didcot, Oxon
• S.L. Smith
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• H. Witte, T. Yokoi
  JAI, Oxford

The next generation of lepton flavour violation experiments will use high intensity and high quality muon beams. Such beams can be produced by sending a short proton pulse to the pion production target, capturing pions and performing RF phase rotation on the resulting muon beam in an FFAG ring, which was proposed for the PRISM project. A PRISM task force was created to address the accelerator and detector issues that need to be solved in order to realise the PRISM experiment. The parameters of the initial proton beam required and the PRISM experiment are reviewed. Alternative designs of the PRISM FFAG ring are presented and compared with the reference design. The ring injection/extraction system, matching with the solenoid channel and progress on the ring's main hardware systems like RF and kicker magnet are discussed. The activity on the simulation of a high sensitivity experiment and the impact on physics reach is described. The progress and future directions of the study are presented in this paper.