Electron Model Components and CostingC. Johnstone

Summary talk, C. Johnstone

FFAG04

Oct 12-16, 2004

KEK, Tsukuba, Japan

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.

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.

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.

• 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.