Hi Djamel, We had a short discussion wit Flemming and he claimed that (at least for D4) it is better to use effective edges rather than the physical gap edge planes. The effective edges are very close to Field Clamps of the magnets that in fact define the magnet geometrical acceptance. I forgot to change physical edge to effective edges, but it has to be corrected. Pawel. Djamel Ouerdane wrote: > Hi all, > > I have 2 questions and especially need a feedback on those from people > working on MRS data: > > 1- While analyzing data (MRS or FS), I thought it would be really useful > to keep the info as to where the track hits the inside of the magnet gap > and keep these tracks for background study. So, I went through the > BrMagnetVolume method GetSwimStatus which seemed to me the best place for > that. I discovered that the magnet front and back planes used were NOT the > effective edge planes but the physical gap edge planes. Does it matter ? I > think so, especially for D5 (84cm - 76cm = 8cm ~ 0.1% error on the gap > length). > > 2- Now concerning the MRS PID, I'm totally puzzled about the asymmetry > between left and right bent particles which show up in mass2 vs P. The tof > calibration was done with taking blindly the momentum from D5. If you > remember a previous email, I removed all calibrations depending on the Y > track position (due to vDrift fluctuations) and hence, the tof cal only > depends on the track quality in X and Z (therefore momentum). > > I know since I could see it that at least JH had a better symmtrized mass2 > distribution. If there's a trick I don't know, a correction I forgot, a > calibration I ignored, please let me know ASAP. > > Ciao > Djam > > -- > Djamel Ouerdane ------------------------------------------o > | Niels Bohr Intstitute | Home: | > | Blegdamsvej 17, DK-2100 Ø | Jagtvej 141 2D, | > | Fax: +45 35 32 50 16 | DK-2200 Copenhagen N | > | Tel: +45 35 32 52 69 | +45 35 86 19 74 | > | http://www.nbi.dk/~ouerdane | > | ouerdane@nbi.dk | > o---------------------------------------------------------o -- ---------------------------------------------------------------------- | 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 | ----------------------------------------------------------------------
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