Transcript ppt
GLAST LAT Project Instrument Analysis Meeting– May 27, 2005 GLAST Large Area Telescope: Gamma-ray Large Area Space Telescope TKR Bad strips analysis update Hiro Tajima (SLAC) TKR [email protected] 650-926-3035 Hiro Tajima, TKR Bad Strips 1 GLAST LAT Project Instrument Analysis Meeting– May 27, 2005 New TKR Recon Side Effects • Shadow of dead strips. – Tracking stops when no hit can be associated. • Inclusion of dead strips to recon clusters. – Some dead strips appears alive. • This is a feature of recon. – Not all dead strips are affected. (not understood) Digi clusters Recon clusters strip Id Hiro Tajima, TKR Bad Strips 2 GLAST LAT Project Instrument Analysis Meeting– May 27, 2005 Cluster from Digi hits • Form clusters from digi hits. • Collect all clusters consistent with recon track. – Multiple clusters per layers allowed. – Requires geometry information. • Tower center and layer z position can be obtained from recon clusters. • Ladder gap and strip pitch is hard coded. – These parameters are very likely to be invariant. Cluster – track (mm) Hiro Tajima, TKR Bad Strips 3 GLAST LAT Project Instrument Analysis Meeting– May 27, 2005 Result of digi clusters • Digi clusters fix both problems. strip Id Hiro Tajima, TKR Bad Strips 4 GLAST LAT Project Instrument Analysis Meeting– May 27, 2005 Utilization of Track Position • Use track position “occupancy” as a reference to calculate Poisson probability for each strip. – Useful to get shape, not absolute rate. strip Id Track position Strip occupancy Hiro Tajima, TKR Bad Strips 5 GLAST LAT Project Instrument Analysis Meeting– May 27, 2005 Layer Occupancies • Under study Track position Digi clusters Recon clusters Accepted Digi clusters Plane Id Hiro Tajima, TKR Bad Strips 6