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). So Djamel, coulkd you clarify whta the intention here is ? Just for general information - do not expect much communication from most US folks in the next day or so. Pawel Staszel wrote: > 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 | > ---------------------------------------------------------------------- > >
This archive was generated by hypermail 2b30 : Thu Nov 22 2001 - 12:12:11 EST