Summary: FFAG WORKSHOP nonscaling electron model muon FFAGs

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Summary FFAG WORKSHOP nonscaling electron
modelmuon FFAGs

• C. Johnstone Fermilab

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Electron Model

• Advanced understanding and full lattice designs
• Linear field lattices Berg, Koscielniak,
  Johnstone, Keil, Trbojevic
• Isochronous lattices G. Rees
• Full simulation, tracking and error analysis
• Meot full simulation tools fringe field
  ability
• Machida alignment and field quality analysis
• Keil error studies with MAD

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Electron Model Technical Specifications

• Full ring
• Factor of 2 energy gain
• Lattice choice doublet min(costphase-slip)
• Periodicity 42 identical cells
• Injection
• Injector 8-35 MeV Daresbury Energy Recovery
  Superconducting Linac (ERSCL)
• Injection energy 8-12 MeV, 130? - 140?/cell
• Extraction energy 16-24 MeV, 25 ? 30 ?/cell

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Electron Model Goals

• POP of nonscaling FFAG accelerator (muon
  accelerator demonstration other applications?)
• Large momentum compaction-reduced apertures
• Multi-resonance crossing without correction
• Includes integer and half integer resonances
• Bucketless acceleration
• 1 and 2 fixed points, 5-20 turns
• Transverse and longitudinal dynamics
• Under phase-slip conditions relative to rf
• Chromatic dependence of beta functions through
  acceleration cycle
• Symmetric and asymmetric parabolic pathlengths

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Electron Model Magnet Specifications

• Preliminary magnet design permanent magnet
  trim coils (slot constraints)
• For 10 MeV injection
• Permanent dipole component of 1.5 kG
• Permanent quad component of 4T/m
• Quad trim coil provides /- 20
• Variation in dipole component can be provided by
  varying injection energy or side plate location
• Slot length 10-12 cm
• PM/core length 5-7cm
• Magnet spacing 5-7 cm

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Electron Model Magnet
Dipole plus quad field lines
?
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Electron Model Magnet Tolerances

• Good-field region 5-20 turns
• 1 gradient error at /-5cm
• Thermally stable PM material
• 8 cm allows injection/extraction? no special
  magnets in ring
• 1Hz operation or less
• No cooling
• No eddy current problems

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Electron Model Diagnostics

• OTR foils cameras
• Transverse phase space profiles
• Bunch train 109/bunch
• Single bunch operation checking
• Longitudinal distribution streak camera
• Resistive wall monitor verify beampipe size and
  cut-off frequencies
• 1.3 GHz BPMs
• Single and multi-bunch design
• Fit inside magnets
• 20 micron resolution

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Fermilab Main Injector bpm
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Electron Model RF specifications

• 1.3 GHz to match Daresbury Linac
• Frequency variation to change fixed points
• 21-25 cm straight required for installation
• About half of the 42 cells will have rf.

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What can we afford under a NEST

• ¼ of the ring or 10 cells (0.5 million Euros
  with 30 contingency)
• Requires design and engineering contributions on
  part of participating institutions.
• Fermilab will propose funding design and possibly
  a prototype magnet to lab management
• Control system/operation Daresbury
• Others
• Hardware contributions
• Streak and CCD cameras, OTR assemblies
• Inventory institutions

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What would a nonscaling arc demonstrate

• Achieve high momentum compaction and nonscaling
  optics
• Verify nonscaling lattice over the factor of two
  change in energybefore building full ring!
• Prototype and get diagnostics operational
• Multi-bunch single bunch operation
• Intensity dependence and other systematics
• Optics
• Beam-based alignment
• Beam-based field measurements
• Check variation of optics and orbits using
  variable injection energy !!! fringe field
  characterization !!!

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International Collaborative Projects

• Role and contributions to PRISM?
• Proton FFAGs?
• Define working groups?
• Range of applications medical group
• SBIR applications? Reactor FFAGs