Electron Model Components and Costing

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Electron Model Components and Costing

• C. Johnstone

Summary talk, C. Johnstone FFAG04 Oct 12-16,
2004 KEK, Tsukuba, Japan
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Electron Components and Costing

• At the proposed site, 30 m is available in
  circumference
• Technical parameters chose to optimize the
  cells are 15 cm for the rf, 5 cm for the magnet
  and intermagnet spacing
• Both a FODO and FDF cell length is 0.4 m
• This implies 75 cells could be implemented and it
  has been found that 30 are too few to simulate
  muon FFAG rings. 80 would be optimal, but costs
  may prohibit this number.
• Assuming 40 cells and 1.5-2 kG bend field for
  the reference energy gives 18-24 MeV/c as the top
  energy of the ring. 80 cells will double the top
  energy.

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Magnets

• For a 2kG bend field, one requires 3 or more kG
  poletip field. One would prefer not to build
  multiple magnet designs which increases the cost
  and engineering.
• One magnet which meets this criteria is the
  upgrade Fermilab linac quadrupole (the 2 long
  green magnet shown on the first page). Its peak
  poletip field is near 3.5 kG, the poletip bore is
  2 and has a BPM design which fits inside the
  quad. With a BPM installed the aperture is 1.5.
  This is ideal for the 2-3 cm orbit swing
  envisioned for this ring. It is pulsed at 15 Hz
  and has a power supply design already engineered.
  A standalone 15 Hz DA system, VME based is in
  place which can be interfaced to any existing
  controls system.

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Other components
From the picture one can also see a short single
wire scanner to the right of the quad, also an
ideal size to use for a multiwire. The insertion
length of the quad is 4(1 on either side),
which ideally corresponds to the 5 cm intermagnet
spacing if an FDF configuration is used.
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• IF the FODO or doublet lattice configuration is
  used, then the beam clears either the BPM or the
  poletip by 1/3-1/2, respectively, in the
  defocussing, CF magnet and the large orbit swing
  is well centered in the F quadrupole.
• For a FDF configuration, two types of magnets may
  be required since symmetrization of the energy
  parabola requires the extraction energy to be
  located a the 0-field point in the F quadrupole
  hence the orbit swing at low energy is close to
  the beampipe, but this needs investigation before
  ruling out the proposed magnet.
• The cost of a few kG pulsed magnet is 6k.