EV-MCP gap

Comparison of the Barrel DIRC 's performance for configuration with optical grease and air gap between prism and MCPs.

  • PandaRoot simulations without field
  • configuration with narrow bars, 3 layer spherical lens, and 8 MCPs layout with ~17 mm gap
  • pions and kaons @ p = 3.6 GeV/c @ phi = 10.825 deg
  • time-imaging reconstruction with full-simulated pdfs
  • 30k tracks for pdf generation (per each particle species); 5k for determining separation
  • ~2 mrad tracking resolution
  • realistic time precision
  • QE=26(32)% ( blue curve). CE=95%
  • spatial QE = 1

Event display screenshot for configuration with 0.4 mm air gap (lightblue - MCP window; red - MCP cathode) and for 25 deg polar angle track:

Photon yield:

Separation power: