Experimental results in 150MeV proton FFAG

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Experimental results in 150MeV proton FFAG
ISS_at_KEK, Jan. 06

• M. Aiba (KEK)
• For KEK FFAG Gr.

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Contents

• Purpose of 150MeV FFAG project
• Machine parameters
• COD correction and resonance crossing
• Hardware improvement in RF system
• Beam extraction with 100Hz operation
• Summary

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Purpose of 150MeV FFAG

• To establish a prototype FFAG for various
  applications.
• Beam extraction from FFAG for the first time
• Rapid cycling
• Test experiments for applications using extracted
  beam

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Machine parameters
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CODSource Correction scheme

• RF cores disturb fringing field.
• Additional two dipoles to correct COD.

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Resonance crossing (3nx11)

• Horizontal tune changes from 3.6 to 3.8
• Characteristics of crossing 3nx11
• Non structure resonance excited by COD feed
  down.
• Crossing near injection energy.
• Injection septum determines horizontal
  aperture.

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Crossing direction dependence
Phase space topology with dominant nonlinearlity
?
(distance from resonance)
1.(a)?(e)
Particle trapping
(Proposed by A.W.Chao M.Month)
2.(e) ?(a)
Emittance growth (150MeV FFAG)
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Particle trapping
Emittance growth
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Experiment data
Beam intensity during acceleration
BlackSuitable dipole correction
Red70 dipole correction
Crossing point
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Hardware improvement in RF system

• Enhancement of RF system

RF voltage 5kVpp 12kVpp Rapid
cycling has become possible.
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Beam extraction

• Fast extraction with kicker and septum
• Try to realize 100 extraction efficiency

Top and side drawings of the septum magnet
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Beam extraction experiment(1)
Beam separation with kicker
Separated beam with kicker
Circulating beam
5mm
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Beam extraction experiment(2)
Experiment set up
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Summary
150MeV proton FFAG has been developed to be a
prototype of FFAG for various applications.
Experimentally,

• COD and resonance crossing has been overcome.
• Improvements in RF system to realize rapid
  cycling.
• 100Hz operation was successful.
• Basic accelerator RD studies has been
  completed.