GuineaPig Output

We are investigating input/output from Glen White's IP feedback simulation. There are a few not so nice features and some semi-surprises (to me at least).

• Files are very large (20 GB/bunch train)
• Input beams have little energy variation
  RMS: 1.6 MeV e^-, 100 keV e⁺
• Even so, lumi-weighted root(s) varies by ~100 MeV (RMS) along the train

Truncated mean of lumi-weighted invariant mass vs. bunch number.

Simulation (XLSIM?)

We have started work on using BDSIM to simulate the extraction line from IP to dump.

• Geant4 and BDSIM installed
• BDSIM will parse x-line optics deck (mostly) correctly
• Working on understanding BDSIM geometry building in more detail
• Drive simulation with GuineaPig output

Detector Studies

A new Fera ADC and renewed student interest has brought us back to the question of measuring Cherenkov yield to few MeV electrons in small (100 or 600 micron) quartz fibers.

This measurement is difficult in a lab because:

• Small fiber diameter means small active area
• Very low photoelectron yeild per incident particle (0.1% or less?)
• Low rate sources (90Sr or cosmic rays)

New setup:

• Trigger plane made from 500 micron square scintillating fibers
• Coincidence layer made from close-packed 100 micron scintillating fibers
• Quartz fibers sandwiched between two planes, total active area ~30 cm²