Hodoscope Calibrations

This is directory contains the code for calibrating the hodoscope timing in SHMS and HMS

Directory structure

• tofcal.f : Fortran code which execute the calibration.
• Maketof : Script to compile tofcal.f and make executable tofcal
• tofcal.inp : Input file for tofcal.f
• shmstofcal.inp : Version of tofcal.inp for SHMS
• hmstofcal.inp : Version of tofcal.inp for HMS

Compiling code

• Execute ./Maketof

Running code

• First replay data by adding either line to replay script ** HMS: gHcParms->Load("PARAM/HMS/HODO/CALIB/htofcalib.param"); ** SHMS: gHcParms->Load("PARAM/SHMS/HODO/CALIB/ptofcalib.param");
• The replay will put the new file : hfort.37 or pfort.37 in the CALIBRATION/hodo_calib directory
• Copy either hmstofcal.inp or shmstofcal.inp to tofcal.inp
• Execute ./tofcal
• Print out info on the initial chi2 of data and final chi2 of the fit.
• Creates file tofcal.param
• Edit the parameters in tofcal.param into either PARAM/HMS/HODO/hhodo.param or PARAM/SHMS/HODO/phodo.param

Brief decription of code

• The code fits tcorr = time - offset - path * velocity - adccor / sqrt(ADC)
• Uses paddle 10 positive PMT on plane 1 as the reference PMT ( offset fixed at 0)
• To get data file name. Reads-in the input file: tofcal.inp
• Opens data file
  • "0" line separates events
  • Should have pair of neg and pos PMTs for each paddle
  • Format is : iside ipl ipad tdcval_uncorr pathl zcor tdcval_corr adcval
    • iside = 1,2 for pos and neg PMT
    • ipl = plane number
    • tdcval_uncorr = raw time in ns. The program uses this in optimization.
    • pathl = distance for focal plane to the paddle using the track
    • zcor = time (ns) for the particle to go from focal plane to paddle. Correction subtracted from tdcval_uncrr
    • tdcval_corr = the corrected time in ns. Not used by program. Just gives the initial chi2.
    • adcval = ADC value used in fit
• Loops through data determines the number of hits in each PMT. Will only include PMT if the number of hits > 100.
• Again loops through the data filling array with time difference between all pairs PMTs, pathl and adcval.
• Use the CERNLIB routine deqn to invert the matrix and determine the fit parameters.