Mattione Update 09072011
From GlueXWiki
FCAL Time Reconstruction
- The reconstructed FCAL time is significantly offset from the simulated times.
- hd_dump of DFCALShower, DFCALTruthShower, and DFCALHit. Note that both the DFCALShower and DFCALHit times are ~2+ ns greater than the DFCALTruthShower times.
Event: 1 DFCALShower: E(GeV): X(cm): Y(cm): Z(cm): t(ns): -------------------------------------------- 3.27 -8.27 63.70 642.36 21.16 //Photon generated at target center (0, 0, 65), so path length = 580.922 and t should be = 19.377 DFCALTruthShower: x(cm): y(cm): z(cm): px(MeV/c): py(MeV/c): pz(MeV/c): E(MeV): t(ns): primary: track: type: --------------------------------------------------------------------------------------------- -8.0 61.7 625.3 -44.8 343.8 3123.6 3142.732 18.8 1 1 1 //Photon generated at target center (0, 0, 65), so path length = 563.744 and t should be = 18.8 //similar, additional hits were present but were truncated DFCALHit: row: column: x(cm): y(cm): E(MeV): t(ns): ---------------------------------------------- 44 26 -12.0 60.0 42.050 21.082 //similar, additional hits were present but were truncated
- In programs/Simulation/HDGeant/hitFCal.c the times saved to the s_FcalTruthShowers_t and s_FcalTruthHit_t objects are different: the s_FcalTruthHit_t times (which are later smeared and converted to DFCALHit objects) are increased to account for what looks like light propagation to the PMTs (line ~192). Perhaps this isn't being taken into account in the DFCALCluster reconstruction code??? I'm not really familiar with it, so I'm hoping that someone who is will take a look at this.