02/14/00Jianchun (JC) Wang1 Outline The idea behind the code Code structure and its usage Test on a magnet run Plan Jianchun Wang 02/14/00

Jianchun (JC) Wang2 Motivation Existing hand alignment –too slow –difficult to deal with correlated parameters Minuit alignment –work on saved tracks (avoid unnecessary calculation) –correlated parameters can be fitted together –can be automated

02/14/00Jianchun (JC) Wang3 Code structure  First stage: output track for later fitting user(‘event’)  mn_write_track  Subsequent stages: read in track and fit user(‘endrun’)  mn_prepare_fit  mn_read_track  mn_fit_geo  mn_geo_copy  mn_geo_chi2  mn_geo_copy  mn_derived_geom  mn_fit_tracks

02/14/00Jianchun (JC) Wang4 Output Tracks  Only one track in the event  At least two good Y hits  Number of Planes with hits is kept  Local position and sigma are kept  Chi2 of Kalman fit is also kept for comparison ( y slope floating, all y information in the fit)  Output file name “track_out.dat”

02/14/00Jianchun (JC) Wang5 Preparation for the fit Links of geometry planes to Kalman planes created only once to save time Tracks input from file “track_in.dat” All track properties stored with a format suitable for Kalman fitting Planes can be dropped at this stage

02/14/00Jianchun (JC) Wang6 Minuit fitting  Parameters for fit –Provided by “mn_skip.dat”, changeable during run –Manipulate parameters interactively in Minuit  Parameter transfer –New geometry parameters in monitor format (mn_geometry.dat) –Geometry parameter  Minuit parameter  Function of the fit –Chi2 of Kalman fit averaged over n.o.f and ntrack

02/14/00Jianchun (JC) Wang7  2 of Kalman fitting Magnet run 7236 (15 o ) 20K events 10K tracks selected Hand alignment before create track file MINUIT fit use only simple fit with part of parameters  2 is not normalized to n.o.f

02/14/00Jianchun (JC) Wang8 Resolution of FPIX1 FPIX1 pspray at 15 o The resolution is not changed (~11  m) For rough comparison only (magnetic field effects)

02/14/00Jianchun (JC) Wang9 Residual of FPIX0 FPIX0 pstop rotated and placed in magnetic field (~ 17.5 A) Only two pixel clusters shown, and the improvement is only due to a bug fixed in eta correction For comparison only

02/14/00Jianchun (JC) Wang10 What is next ?  MC test to have objective evaluation (Rob has running MC)  Input & output control  Create procedure of the fitting  Make it more automatic  Align all runs ( how to share the work, and CPU availability)