Particle ID in the MICE Beamline

1
Particle ID in the MICE Beamline
Paul Soler, Kenny Walaron University of Glasgow
and Rutherford Appleton Laboratory
MICE UK Meeting 3 March 2004.
2
Aims

• Carry out particle identification in the MICE
  beamline using scintillation detectors.
• Use dE/dx signature to differentiate between
  protons and pions/muons at input and output of
  solenoid.
• Use PID information to qualify and monitor
  beamline simulation.

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MICE Beamline
Working assumption solenoid magnet inside the
beamline

• Transport of particles in MICE beamline (LAHET
  simulation from proposal)

• Insert scintillator recording planes for PID

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Beamline Proposal

• Particle composition of beamline (LAHET
  simulation from proposal, assuming 25o angle )

Yields at 3 m from downstream dipole
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GEANT4 Beamline Simulation

• MICE beam simulation prepared in GEANT4 (see Tom
  Roberts presentation 24/9/03) showed some
  differences with proposal

• Mu/sec at Diffuser1
• MICE Proposal 3,000
• This computation 130,000
• Major differences between simulations (factor
  30)
• 700 MeV/c protons ? 800 MeV/c
• Target geometry
• Height 2 mm ? 10 mm
• Diffuser1 geometry
• r20 cm ? 25 cm
• Diffuser1-B2 3 m ? 2 m

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GEANT4 Beamline Simulation

• Details inserted into GEANT4 simulation
  g4beamline (from Tom Roberts simulation)

• Layout from LAYOUT-MICE 14May03
• Bend 1 is 60, Bend 2 is 30
• Target to Diffuser1 is 18.8 m
• Quad (Type IV) and Bending Magnet (Type I)
  parameters are from RAL drawings and tables.
• Fringe fields for Bending Magnets were computed
  via Laplaces equation quads are ideal (no
  fringe fields).
• Bend 1 is tuned for 300 MeV/c pions
• Bend 2 is tuned for 200 MeV/c muons
• Quads are tuned for maximum mu/pi ratio at
  Diffuser1 (using minuit) the triplet is
  configured DFD (20 better than FDF)
• Target re-oriented so a long edge is along the
  beam.

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GEANT4 Beamline Simulation

• Input beam into g4beamline

• Pi beam
• 200 MeV/c lt P lt 400 MeV/c (uniform)
• dxdz and dydz generated to cover Q1 aperture
  (uniform)
• Target is 10 mm high, 10cos(25) mm wide
  (uniform)
• All materials kill tracks instantly, without
  secondaries

P at Q1 for mu at Diffuser1
Momentum at Diffuser1
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g4beamline

• Have commenced to work with g4beamline simulation
• Latest release v 0.5 is still beta version
• Modifications have been made to simulation to add
  scintillator elements to be used for particle
  identification
• Can run simulation as it is but we have come up
  with some technical difficulties during
  compilation of modifications that need to be
  resolved
• So far, g4beamline is being run by a few people
• Need to increase community of users. Suggestion
  would be to include g4beamline into G4MICE
  framework, so it may be supported centrally

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Particle ID in beamline

• Particle identification in beamline dE/dx for
  proton separation
• Insert slabs of scintillator upstream and
  downstream of solenoid for PID
• Scintillator protons less than 400 MeV/c deposit
  gt8.5 MeV/cm, while pions/muons deposit 1.6-4.0
  MeV/cm

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Conclusions

• MICE beam simulation prepared in GEANT4 by Tom
  Roberts
• Have started working with it, but still need to
  learn more about programme and try and adapt it
  to local environment
• In the process of including particle ID elements
  to enable design of scintillators (ie.
  segmentation, thickness) to cope with particle
  rates