Author: Palmer, R.B.
Paper Title Page
TUPPR011 Six-dimensional Bunch Merging for Muon Collider Cooling 1831
  • R.B. Palmer, R.C. Fernow
    BNL, Upton, Long Island, New York, USA
  • D.V. Neuffer
    Fermilab, Batavia, USA
  Funding: Work supported by US Department of Energy under contracts DE-AC02-98CH10886 and DE-AC02-07CH11359.
Muons for a Muon Collider are diffusely produced from pion decay. They are first phase rotated into a trains of bunches. The trains are ionization cooled in all six dimensions until they can be merged into single bunches, one of each sign. They are then further cooled in six dimensions before acceleration and injection into the collider. This merging matches more efficiently into the second phase of cooling if the merging is also in six dimensions. A scheme to do this is proposed. Groups of 3, of the initial 12, bunches are merged longitudinally into 4 longer bunches, using rf with multiple harmonics. These 4 are then kicked into 4 separate (trombone) channels of different lengths to bring them to closely packed transverse locations at the same time. Here they are captured into a single bunch with now increased transverse emittance.
THPPC033 Progress on a Cavity with Beryllium Walls for Muon Ionization Cooling Channel R&D 3356
  • D.L. Bowring, A.J. DeMello, A.R. Lambert, D. Li, S.P. Virostek, M.S. Zisman
    LBNL, Berkeley, California, USA
  • D.M. Kaplan
    Illinois Institute of Technology, Chicago, Illinois, USA
  • R.B. Palmer
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Muon Accelerator Program (MAP) collaboration is working to develop an ionization cooling channel for future muon colliders. The ionization cooling channel requires the operation of high-gradient, normal-conducting RF cavities in solenoidal magnetic fields up to 5 T. However, experiments conducted at Fermilab's MuCool Test Area (MTA) show that increasing the solenoidal field strength reduces the maximum achievable cavity gradient. This gradient limit is characterized by an RF breakdown process that has caused significant damage to copper cavity interiors. The damage is likely caused by field-emitted electrons, focused by the solenoidal magnetic field onto small areas of the inner cavity surface. Local heating may then induce material fatigue and surface damage. Fabricating a cavity with beryllium walls would mitigate this damage due to beryllium's low density, low thermal expansion, and high electrical and thermal conductivity. This poster addresses the design and fabrication of a pillbox RF cavity with beryllium walls, in order to evaluate the performance of high-gradient cavities in strong magnetic fields.
THPPD037 Design Studies of a Dipole with Elliptical Aperture for the Muon Collider Storage Ring 3590
  • M.L. Lopes, V. Kashikhin, J.C. Tompkins, A.V. Zlobin
    Fermilab, Batavia, USA
  • R.B. Palmer
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported partially by US-MAP and by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The requirements and operating conditions for superconducting magnets used in a Muon Collider Storage Ring are challenging. About one third of the beam energy is deposited along the magnets by the decay electrons. As a possible solution an elliptical tungsten absorber could intercept the decay electrons and absorb the heat limiting the heat load on superconducting coils to the acceptable level. In this paper we describe the main design issues of dipoles with an elliptical aperture taking into consideration the field and field quality. The temperature margin and the forces in the coils are presented as well.
THPPD048 15+ T HTS Solenoid for Muon Accelerator Program 3617
  • Y. Shiroyanagi, R.C. Gupta, P.N. Joshi, H.G. Kirk, R.B. Palmer, S.R. Plate, W. Sampson, P. Wanderer
    BNL, Upton, Long Island, New York, USA
  • D.B. Cline
    UCLA, Los Angeles, California, USA
  • J. Kolonko, R.M. Scanlan, R.J. Weggel
    Particle Beam Lasers, Inc., Northridge, California, USA
  Funding: This work is supported by the U.S.Department of Energy under Contract No. DE-AC02-98CH10886 and SBIR contract DOE Grant Numbers DE-FG02-07ER84855 and DE-FG02- 08ER85037.
This paper will present the construction and test results of a ~10 T insert coil solenoid which is part of a proposed ~35 T solenoid being developed under a series of SBIR contracts involving collaboration between Particle Beam Lasers (PBL) and Brookhaven National Laboratory. The solenoid has an inner diameter of 25 mm, outer diameter of ~95 mm and a length of ~70 mm. It consists of 14 single pancake coils made from 4 mm wide 2G HTS conductor from SuperPower Inc., co-wound with a 4 mm wide, 0.025 mm thick stainless steel tape. These are paired into 7 double pancake coils. Each double pancake coil has been individually tested at 77 K before assembly in a complete solenoid. The solenoid is nearly ready for a high field test at ~4K.