Effect of delta-electrons in simulation of beam electrons

1
Effect of delta-electrons in simulation of beam
electrons

• V. Tumakov

2
MECO setup

• Clear bore has hexagonal cross section with
  minimal distance to the axis 24.15cm
• Vacuum closure is 1 cm Aluminum plate located at
  z -998cm
• with 2mm thick and 15cm in diameter Aluminum
  window in it on PS axis.
• Production target the gold (R4.5mm)
• Water thickness is 300µ, thickness of Titanium
  envelope is 500 µ.
• Proton beam was simulated according the proton
  beam optics, sx 1.5mm, sy0.67mm
• Mylar window (300µ )was placed in the middle of
  transport solenoid.
• Collimators
• Y1cm, Y -19cm were used in the middle of the
  transport solenoid.
• R15cm collimator was used at entrance of the
  transport solenoid,
• R12.8cm copper collimator was used at the
  entrance of the detector solenoid together with
  12 copper rings with inner radius R8cm and
  thickness 60µ each.

3
Simulation with delta-electrons

• Full MECO setup simulation with delta-electrons
  doesnt work
• Instead
• Simulation with delta-electrons and
  
  1MeV cut for electrons and positrons
• Simulation with delta-electrons tracing
  
  all particles only near the
  production target
  writing kinematics
  into the file.
• Simulating electrons or positrons with
  
  energy below 1MeV starting with kinematics
  
  registered on previous step

4
Results

• Electrons and positrons with energy below 1 MeV
  do not contribute into the tracker rates
• Particle flux at DS entrance

Energy cut e- /p late e- /p, 10 -4 e /p late e /p, 10 -4 µ- /p, 10 -3
Without d-el Ekin10keV 0.230 3.10.2 0.0345 1.20.2 1.850.05
With d-el. Etot 1MeV 0.300 5.80.5 0.0350 1.50.2 1.750.08

• Particle rates at L-tracker

late e- /p, 10 -4 Probability Av. straw per ev Rate, kHz/wire
Withoutd-el. 3.10.2 5.00 x 10-4 1.25 213
With d-el. 5.80.5 5.33 x 10-4 1.48 509

• Conclusion Delta-electrons increase
  
• total flux of beam electrons by 30
• flux of late electrons and rate in the tracker by
  factor ?2.