Bunched-Beam Phase Rotation- Variation and 0ptimization

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Bunched-Beam Phase Rotation-Variation and
0ptimization

• David Neuffer,
• A. Poklonskiy
• Fermilab

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0utline

• Introduction
• Study 2AP? ???
• High-frequency Buncher and ???? Rotation
• Study 2A scenario, Obtains up to 0.2 ?/p
• Variations
• Shorter rotator (52m ? 26m), fewer rf frequencies
• Short bunch train (lt 20m)
• Optimization .
• Muon Collider scenarios
• Gas filled cavities
• Higher gradients?
• Cooling in buncher and rotator
• Polarization ??

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Study2AP June 2004 scenario

• Drift 110.7m
• Bunch -51m
• V?(1/?) 0.0079
• 12 rf freq., 110MV
• 330 MHz ? 230MHz
• ?-E Rotate 54m (416MV total)
• 15 rf freq. 230? 202 MHz
• P1280 , P2154 ?NV 18.032
• Match and cool (80m)
• 0.75 m cells, 0.02m LiH
• Realistic fields, components

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Shorter bunch Rotator

• Drift 123.7m (a bit longer)
• Bunch -51m
• V 3(z/LB) 3 (z/LB)2 MV/m
• ?(1/?) 0.0079
• ?-E Rotate 26m
• 12 MV/m ( 2/3)
• P1280 , P2154 ?V 18.1
• (Also P1219 , P2154, ?V 13.06)
• Match and cool (100m)
• V 15 MV/m ( 2/3)
• P0 214 MeV/c
• 0.75 m cells, 0.02m LiH
• Obtain 0.22 ?/p

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Short bunch train option

• Drift (20m), Bunch20m (100 MV)
• Vrf 0 to 15 MV/m (? 2/3)
• P1 at 205.037, P2130.94
• ?N 5.0
• Rotate 20m (200MV)
• ?N 5.05
• Vrf 15 MV/m (? 2/3)
• Palmer Cooler up to 100m
• Match into ring cooler
• ICOOL results
• 0.12 ?/p within 0.3? cm
• Could match into ring cooler (C40m) (20m train)

40m
60m
95m
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FFAG/ µ-µ- Collider influenced

• Example I (250 MeV) 100MHz
• Uses 90m drift 100m 200?100 MHz rf (5MV/m)
• Captures 250?200 MeV ?s into 250 MeV bunches
  with 80 MeV widths
• Example II (125 MeV) 50MHz
• Uses 60m drift 90m 100?50 MHz rf (lt3MV/m)
  180MV total
• Captures 125?100 MeV ?s into 125 MeV bunches
  with 40 MeV widths

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Advantages of high-pressure cavities

• high gradient rf
• In magnetic fields B1.75T, or more
• With beam
• Change cavity frf by ??
• Can Integrate cooling with capture
• Capture and phase-energy rotation cooling
• Can get high-gradient at low frequencies (30, 50,
  100 MHz ???)
• Beam manipulations
• Polarization

Research can be funded
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Simplest Modification

• Add gas higher gradient to obtain cooling
  within rotator
• 300MeV energy loss in cooling region
• Rotator is 51m
• Need 6MeV/m H2 Energy loss
• 9MeV/m if cavities occupy 2/3
• 30 Liquid H2 density
• 100atm, 90ºK gas
• Alternating Solenoid lattice in rotator
• 21MV/m rf
• Lattice changes
• Try shorter system

Cool here
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Polarization for µ-µ- Colliders

• Start with short proton bunch on target lt 1ns
• Before p?µ? decay, use low-frequency rf to make
  p-beam more monochromatic
• 50MV in 5m?
• Drift to decay (10m?)
• Higher energy µs pol.
• Lower energy µs pol.
• ¼ Phase-Energy rotation
• 10m
• Rebunch at 2 frequency
• s in one bunch
• -s in other bunch
• 50 ? 100MHz ??

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Some initial simulations (K. Paul)

• Initial beam from MARS
• 5m from target - 76 p
• 200MHz rf, 50 MV/m
• 5m from target then 2m rf

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Summary

• High-frequency Buncher and ???E Rotator
  (?-Factory)
• Variations (see Poklonskiy),
• Shorter systems ??
• Lower Frequency (fewer bunches).
• Gas-filled rf cavities
• Higher gradient??
• Cool in buncher rotator
• Polarization ???
• To do
• Optimizations, Best Scenario, cost/performance
• Consider applications besides ?-Factory µ-µ-
  collider, low-energy muon source

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Meeting Status