29 Mar 2007Tracking - Paul Dauncey1 Tracking/Alignment Status Paul Dauncey, Michele Faucci Giannelli, Mike Green, Anne-Marie Magnan, George Mavromanolakis, Fabrizio Salvatore, Hakan Yilmaz

29 Mar 2007Tracking - Paul Dauncey2 Track finding/fitting changes Checks all hits for consistent track combinations Previously only used first hit in each chamber Allows more (or less) than one track per event Previously always one (unless a chamber had zero hits) Allows for missing hits on track Previously only had four-hit tracks Allows for non-perfect alignment Previously assumed all chamber placement was ideal Same code for CERN and DESY Different constants but algorithm is identical Missing layer in CERN just appears inefficient

29 Mar 2007Tracking - Paul Dauncey3 Constants status Have first version of tracking constants for Run Michele has checked drift velocity against other runs Sees values are mostly stable to ~0.0006mm/ns ~ 2% RunEnergyDC1DC2DC3DC ,03050,02840,03460, ,0310,02820,03860, ,03050,02840,0350, ,03050,02820,03450, ,03030,02820,03420, ,03010,02780,0340, ,50,02990,02780,03390,0294 Scattering matrices found for all DESY energies CERN runs put to zero scattering until calculated

29 Mar 2007Tracking - Paul Dauncey4 Mokka changes X and Y gas drift volumes physically separated Displaced in z by 44mm at DESY, 29mm at CERN Split sensitive volumes into two parts Removes correlation in energy deposits All SimTrackerHits in one collection Labeled by CellID; similar to calorimeters Chamber numbering made more uniform DESY was (from ECAL) DC2, DC1, DC3, DC4 CERN was (from ECAL) DC3, DC2, DC1 Small effect on tracking X/Y split only at 1% level Big effect on digitisation code and book-keeping DESY and CERN look much more similar Debug most of digitisation code only once

29 Mar 2007Tracking - Paul Dauncey5 N.B. Neighbouring chambers placed 1100mm centre-to-centre Fabrizio

29 Mar 2007Tracking - Paul Dauncey6 Fabrizio

29 Mar 2007Tracking - Paul Dauncey7 Digitisation changes Seed digitisation for every event from event number Repeatable if debugging event in middle of run Using ROOT gRandom; is this the standard? Allow more than one TDC hit per event Previously only first SimTrackerHit per layer used Incorporate SimTrackerHit times Some hits from preshowers significantly later Can overlap with real track in space but sometimes not in time Add TDC noise hits Currently flat distribution with rate matched to DESY data Check rate of random hits picked up by tracking Simulate efficiency < 1 Simply drops hits randomly Tune hit smearing to agree better with data

29 Mar 2007Tracking - Paul Dauncey8 Need to cross check against efficiency for track to have hits Michele

29 Mar 2007Tracking - Paul Dauncey9 Simulation request Add Fabrizio’s changes before big Mokka production run Otherwise need to maintain many different versions Change of coordinate system also means “fresh start” would be good Need high statistics samples for all DESY energies Also electrons and pions for all CERN energies (at lower priority) Need to smear beam position and angle to duplicate data better Many distributions look quite different otherwise

29 Mar 2007Tracking - Paul Dauncey10 Want to align ECAL to beam separately Decouples systematics of each detector Allows clean comparison of tracking to ECAL for position measurement Problem is determining average beam position = 0 Barycentre distorted by ECAL pad granularity Difference in x and y due to x layer staggering

29 Mar 2007Tracking - Paul Dauncey11 Hakan Corrected using smoothing (integral) function; assumed Gaussian Mean shifted by 1mm

29 Mar 2007Tracking - Paul Dauncey12 Code organisation

29 Mar 2007Tracking - Paul Dauncey13 Code status Code structure now effectively defined Sent to Roman; he will try it out If it works in his set-up, then load to cvs Remaining issue is database access Working with faked up version currently Not all runs will work until true database interface RunHeader: request for LCParameters information Need run number set for MC Also generally need Data or MC flag Run start/end times Nominal beam energy Location (DESY, CERN, FNAL later) Do these exist? Can missing items be added as part of reconstruction?

29 Mar 2007Tracking - Paul Dauncey14 Next steps Need to reprocess at least one run of each DESY energy E.g Best done centrally to check for interference Cross check all alignment and constants including ECAL changes If time, then repeat for CERN runs Need MC to evaluate scattering matrices for every energy Most of code is directly usable Need to re-evaluate (carefully) alignment, drift velocity Need to re-evaluate (roughly) efficiency, noise rate May not converge for LCWS… Must ensure DESY results are available first Minimum for LCWS; must take priority