• G. Ambrosio, G. Chlachidze, M.J. Lamm, A. Nobrega, E. Prebys
  Fermilab, Batavia
• S. Caspi, H. Felice, P. Ferracin, G.L. Sabbi
  LBNL, Berkeley, California
• T.W. Markiewicz
  SLAC, Menlo Park, California
• J. Schmalzle, P. Wanderer
  BNL, Upton, Long Island, New York

The first Nb₃Sn Long Quadrupole (LQS01) designed and fabricated by the US LHC Accelerator Research Program (LARP) reached its target gradient of 200 T/m during the first test. LQS01 is a 90 mm aperture, 4 meter long quadrupole with Nb₃Sn coils made of RRP 54/61 strand (by Oxford Superconducting Technology). The two-layer coil design is based on the LARP 1m Technological Quadrupoles (TQC and TQS). The mechanical structure is based on the TQS structure implementing an aluminum shell preloaded by using bladders and keys. In 2005 LARP, in agreement with DOE and CERN, set the goal of reaching 200 T/m in a long Nb₃Sn quadrupole by the end of 2009. Achieving this goal in the first test shows the maturity reached by the Nb₃Sn technology for possible application to particle accelerators. Additional tests have been performed aiming at reproducing the performance of the most recent TQ models in order to demonstrate that there are no significant scale-up issues with this technology.

Slides

• V.S. Kashikhin, N. Andreev, V. Kashikhin, M.J. Lamm, A.V. Makarov, G.V. Romanov, K. Yonehara, M. Yu, A.V. Zlobin
  Fermilab, Batavia

Helical Solenoids (HS) were proposed for a muon beam ionization cooling. There are substantial up to 30 MeV/m energy losses during passing the muon beam through an absorber. The main issue of such system is the energy recovery. A conventional RF cavity has diameter which is too large to be placed inside HS. In the paper presented results of dielectric filled RF cavity design. The proposed cavity has helical configuration. Presented Helical Cooling Channel module design which includes: high pressure vessel, RF cavity, and superconducting HS. Discussed parameters of this module sub-systems and shown results of muon beam tracking in combined magnetic and electric 3D fields.

• A.V. Zlobin, E.Z. Barzi, V.S. Kashikhin, M.J. Lamm, V. Lombardo, M.L. Lopes, M. Yu
  Fermilab, Batavia
• G. Flanagan, R.P. Johnson, S.A. Kahn, M. Turenne
  Muons, Inc, Batavia

The Helical Cooling Channel (HCC) is a technique proposed for six-dimensional (6D) cooling of muon beams. The HCC for muon collider and some other applications is usually divided into several sections each with progressively stronger fields, smaller aperture, and shorter helix period to achieve the optimal muon cooling rate. Novel magnet design concepts based on simple coils arranged in a helical solenoid configuration have been developed to provide HCC magnet systems with the desired parameters. The level of magnetic field in the HCC high-field sections suggests using a hybrid coil structure with High Temperature Superconductors (HTS) in the innermost coil layers and Nb₃Sn superconductor in the outer coil layers. The development of the concepts and engineering designs of hybrid helical solenoids based on advanced superconductor technologies, with special emphasis on the use of HTS for high fields at low temperature is the key step towards a practical HCC. This paper describes the conceptual designs and parameters of a short HTS model of a hybrid helical solenoid, and discusses the structural materials choices, fabrication techniques, and first test results.