ntuple->Draw("eff:thr","mod==0&&plane==0&&bfield==1.56&&bias==200&&ang==0");
immediately produces the desired Scurve, as in the figure below.
Similarly,
ntuple->Draw("mult:ang>>hprof","mod==0&&thr==1.0&&plane==0&&bfield==1.56&&bias==80","profs");
hprof->Fit("pol2");
fits the Lorentz angle for the voltage, field and module under consideration.
The run parameters and results stored in each row are listed below:
The variables marked with a * should be used with caution. The spatial resolution can vary between 23 um and 27 because of differences in the alignment and the quality of the fit. At high threshold the number becomes meaningless. The width of the TDC distribution is the distance between the two half-maximum points (not 50 % points). This makes it independent of bad channels etc., but gives problems when the modules are marginally efficient (the 50% points would of course also). It should only be used when the efficiency is over 90%.
The summary Ntuple is available in four different versions. The thresholds filled into the first two ntuples are nominal. The user is responsible for correcting the threshold. The only difference between the two is the treatment of the TDC in relation to the cluster width parameter. After discussion with Szymon Gadomski I decided only to allow clusters close to a track and in the 12 ns TDC window (cluster width is a strongly varying function on charge deposition time). Then, the same Ntuple is available with corrected thresholds according to Gareth's lists for the two chips in the beam based on in-situ calibration 1407 and 1429.
The ROOT2.25 file containing the summary Ntuple (399K)
Version 01-Mar-01 with corrected thresholds (according to calibration run 1407) (244K)
Version 01-Mar-01 with corrected thresholds (according to calibration run 1429) (244K)
I understand some people have had trouble downloading this file to PCs running Windows. The Ntuple is now also available on my AFS account at CERN
/afs/cern.ch/user/v/vos/public/sum_ntuple.root
from where it can be retrieved by ftp.
Last update October 31,
2000
Marcel.Vos@ific.uv.es,
Javier.Sanchez@ific.uv.es,
Gabriela.Llosa@ific.uv.es