Claus, This is what should be done; agree. On the RICH I would think the most likely physical explanation of the difference on the focal plane could be a small ~(.2/150) rotation oif the mirror; afterall this is what the RICH focal plane detector is sensitive to. Flemming ------------------------------------------------------ Flemming Videbaek Physics Department Brookhaven National Laboratory tlf: 631-344-4106 fax 631-344-1334 e-mail: videbaek@bnl.gov > > I've looked at the positions of the image planes of C1 and the RICH (with > the new geometry from the db). There are small offsets - I can see this by > comparing the tracks and the signals in the two detectors. > The question is if we want to change the geometry of the detectors > or if the image planes should be moved a bit (in the PidModules). > > I think the latter is the most correct. The survey geometry (outer edges > of the detectors) is probably right, and I think the offsets come from > small misalignments of the PM arrays. I've therefore introduced the > offsets in the software (as fImagePlaneOffset for the RICH and > fBackPlaneOffset for C1). The best values are of course committed to BRAT. > > Any objections to this way of doing it? > > Claus > > +-------------------------------------------------------------+ > | Claus Jørgensen | > | Cand. Scient. Phone : (+45) 33 32 49 49 | > | Cell : (+45) 27 28 49 49 | > | Niels Bohr Institute, Ta-2, Office : (+45) 35 32 53 07 | > | Blegdamsvej 17, DK-2100, E-mail : ekman@nbi.dk | > | University of Copenhagen Home : www.nbi.dk/~ekman/ | > +-------------------------------------------------------------+ >
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