Diagnostics for FFAG-accelerator

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Diagnostics for FFAG-accelerator

• Takahisa ITAHASHI
• Department of Physics, Osaka Univ. Toyonaka,
  Osaka, 560-0043,Japan

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Contents

• Performances of beam quality for various
  Accelerators
• Diagnostic instruments for a qualified beam
• Diagnostic instruments proposed for PRISM-FFAG
• Conclusion

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Performances of up-dated accelerators (the state
of the art) such as static acc., cyclotron, linac
and synchrotron

• 10-4 energy resolution (Osaka RCNP ring)
• High beam power around 1 M-watt (PSI)
• Precise positioning less than 1-micron (static
  acc.)
• High Luminosity achieved for B-Physics (KEK,
  SLAC)
• Synchrotron orbit radiation ( SPRING-8)

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Tail or skirt part of beam profile or beam
distribution

• The measurement is crucial for high current
  accelerators such as PSI cyclotron
• Achieved extraction efficiency is about 99.99 at
  1mA operation
• In design of ADS a few hundreds MeV 1 GeV, 100
  microA1mA
• Precise knowledge of beam distribution is needed

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6-Dimensional beam behavior should be discussed
in FFAG design

• Recent study of high current beam dynamics
  concerns with non-linear physics issues, which
  includes
• Space-charge dominated beams
• Several resonance effects in FFAG accelerators

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Beam loss due to deterioration beam quality

• Beam envelope in 6-D phase space, in particular
• Transverse-planes
• Characteristic X-rays which are measured
• in a wide dynanic range of intensity lower to
• 10-6 of the peak are very helpful for getting the
  ideas

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Beam loss due to deterioration beam quality

• Longitudinal-plane???microscopic time bunch of
  FFAG beam
• Rf-gamma
• Particle-particle
• For measurement of longitudinal distribution
• Comparison for measurement with FFT

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Diagnostic devices

• Beam transformer x(non
  destructive)
• Wall current monitor x(non
  destructive)
• Pick-ups x(non
  destructive)
• Faraday cup
  
  D(destructive)
• Secondary emission monitor
  -
• Wire scanner
  -
• Wire chamber
  -
• Ionization chamber
  -
• Beam loss monitor x(non
  destructive)
• Gas curtain/jet
  -
• Residual gas monitors x(non
  destructive)
• Scintillator screens
  -
  D
• Scrapers, target
  
  D
• Schottoky scan x(non
  destructive)
• Synchrotron radiation x(non
  destructive)
• Laser-Compton scattering x(non destructive)
  
• Q-measurement x(non
  destructive) -
• Emittance measurement
  -
  D
• Measurement of energy x(non
  destructive) -
  D

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Requirements for diagnostics in PRISM-FFAG

• Comparison with anti-proton production
• Similar facilities as PRISM was ? at CERN and
  will be AD-project at J-PARC(ref. E.Widman).
• AD 200 pi mm mrad and dp/p 6
• stable
• proton beam of capture momentum is
• very helpful for tuning
• various cooling techniques are helpful
  for storage
• Comparison with radio-active ion beam at RIBF
• MUSES /- 10 mrad and dp/p 2.5
• lifetimes of order of 1 microsec.
• cooling and high luminosity are
  considered for collision

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Measurement of beam profile at POP-FFAG with BPM(
non-destructive)

• Measurement of beam profile
• Measurement of beam oscillation
• Measurement of synchrotron freq.
• Measurement of betatron tune

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Injected muon beam

• Dispersion matched at injection
• Central momentum 68 MeV/c
• Requi 6.5 m
• Momentum spread /- 20
• Beam intensity 1011 1012 / sec
• Aperture 30 cm (v) x 100 cm (h)

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Scrapers and measurement targetsDifferential
type beam probe head (for transversal)

• Differential current measurement in horizontal
  and vertical planes
• Probe head has a slightly separated(5mm) tips
• Horizontal stroke is /- 50 cm
• Vertiacal stroke is /- 15 cm or rotated
• Measurable current is about 10pA100nA with log
  amplifier

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Position sensitive solid state counter (energy
and TOF)

• 50 mm x 50 mm silicon strip solid state counter
  for energy measurement
• rf-particle TOF measurement
• Two dimensional measurement between
• position and energy will be avairable

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Sci-Fiber

• Sci-Fiber could be applied for beam diagnostics
  in PRISM-FFAG
• Dr. M. Yoshida-san would have a short comment for
  this issue
• Mr. Takayanagi-san would like to develop the
  device next year.

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• Parameters for PRISM-FFAG Accelerator
• N 10
• K 4.6
• F/D 6.2
• r0 6.5 m for 68 MeV/c
• Half gap 17 cm
• mag. Size 110 cm at F center
• Tune h 2.73 and v 1.58

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Conclusion

• Feasible and actual design of beam diagnostic
  devices in PRISM-FFAG is needed
• Space problem for devices should be solved
• Data taking and display would be needed for easy
  operation of PRISM-FFAG
• Precise measurement in 6-D beam optics would be
  helpful for study of non-linear beam dynamics