Hi Flemming, Below I put some explanations. Flemming Videbaek wrote: > Hi Flemming Ian and all, > > I realized that after having the "full" T1 and T2 > calibration > T2 projected tracks to T3 T4 and T5 detectors have > systematic offsets if dy namely > ~0.5cm for T3 1.3cm and 2.cm for T5. I found that by > changing T2 horizontal rotation > from 0 to -0.126 deg and rising T2 by 0.1cm (from 0.8 to > 0.9cm) we can remove all this offsets and additionally > we get perfect consistency with y-slopes for all T2-DC > combinations. > > Additionally if we rotate T1 horizontally by -0.08 deg and > rise it by 0.5 (from 0.8 to 1.30cm) we obtain > a nice consistency between T1-T2 and T1-DCs. > > >> The raise of 0.8->1.3 IS NOT CONSISTENT with the survey. > And clearly point so some other problem. Possibly > > I think that T2 is consistent with survey, but regarding T1 the rise from .08 to 1.3 points to the problem with TDC offsets (e.g. which TDC is related to zero drift associated with known y position in T1) and rather not to drift velocity because the drift velocity has been already calibrated using T3 tracks. > > uncertainty in the Vdrift determination. > > > > The angles between T1 T2 was afterall determined from > zero-fierlds runs to a very small d(alpha). You > > do afterall change the angle between T1-2T by about > (-0.08-(-0.126))= -0.046 deg == 0.8 mrad which I thibk is > not consistent with the zero-field > > yes, but only in x-direction. At that time I didn't play with T1 and T2 y-slopes because the slopes (and specially dy offsets) where not consistent from run to run. > > runs.? > > > > Once we quickly digested these proposed changes, > > it seems reasonable to put the in DB for QM at least. > > > > Flemming > > > > > > > > > > > -- ---------------------------------------------------------------------- | Pawel Staszel | | Niels Bohr Institute Tb 8 email: staszel@nbi.dk | | Blegdamsvej 17 phone: (+45) 35 32 53 51 | | København Ø FAX: (+45) 35 32 50 16 | | Danmark | ----------------------------------------------------------------------
This archive was generated by hypermail 2b30 : Tue Jun 18 2002 - 11:37:49 EDT