Hi Flemming, > It seems to me we are talking about two different issues. > Both the matching as well as the swim back uses the effective edge, > because that is > what defines where the mag field changes the orbits. > IIt seems to me that Djamel is interested in where tracks > that do NOT go through the magnet comes from - but maybe I get it wrong. > > All tracks in matching magnets already have there positions at the eff > edge recorded in the amtched track > object (Entrance, Exit.) > For the FS tracks they only problem is that the D1 position are in > global coordinate *what I anyhow > don ot think they should be). That's true and I think it has some "historical" origin (I'm talking about the entrance and exit points in global coordinates). I'll change it. Concerning the swim status, I was not clear, sorry. I had D1 in mind in fact since it's the only place where you could have a valid matched track (say in D2) that could originate from a scattering in D1. I would like to keep the "origin" of such tracks as the track vertex member and see how they correlate with the associated time of flight. Now for the 2nd question about the PID, 15mn after I sent my question, I finally made a test (thanks Peter!) where I rotated TPM2 by -0.25 deg. (from 89.903 - default value that I never really checked - to 89.653) I don't know if it is within the limits allowed for tuning the geometry of TPM2 but I then ran the PID for 2 runs with opposite polarity and everything was just great!! I'll make some plots so that you can judge. The fits on the mass2 (negative and positive momenta seperately) give the theoretical values, the track-tof matching has no more systematic offsets (around 0.6 - 0.7 cm before the change). When the plots are available, tell me what you think. Djam
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