Some comment to questions and plots shown by Djam earlier today. a) scalers trigger 6 (and others). A: the DAQ does not have a linear response with time, when the rates are high it may stop storing data on disk for a little while. This is certainly ok, since it is just a time-dependent deadtime. b) another problem is that for certain runs I have seen trigger 6 not being present - a NIM mosule was change late in the run. I suggest this gets moinbitore by having plots of N-trigger 6/sec vs beginning of run (not sequence) N-trigger-6 before LVL0 i.e triggerword 2 c) FFS dang -- the geometry of T1-T2 is unfortunately still un-resolved! The most recent survey confirmed the B values are close to correct. -- this certainly will reflect both matching and dang.. d) How often and how many Vdrift cal have been done? For the run 10286 I used today to check geometry there is clearly a significant difference i Vdrift of T1 and T2 at about 5%. the calibrate runs is not too far away. e) the projection to Bb vertex hides some real problems in FS tracking. As we know from the -au an pp run the projection to the vertex is no good when the tracks are close to the edge of T1. the plot Track vtx on BB plane hides this problem, but two facts are obvious i) there is an offset 3cm that is significant an ii) there is an X(T1) and/or angle difference ; I think we need a plot VTX-diff vs. theta FS that will show the problems clearly. f) D3-d4 momentum. The geometry for T5 has yet to be done properly. A survey is schedule for Monday-Wedn. Hopefully this will help resolve some of the differences. g)the fact that the dx-dy for T3-T4 does not show up at 0,0 points to a geometry issue. cheers Flemming ---------------------------------------------------------------- Flemming Videbaek Physics Department Brookhaven National Laboratory e-mail: videbaek@bnl.gov phone: 631-344-4106 _______________________________________________ Brahms-dev-l mailing list Brahms-dev-l@lists.bnl.gov http://lists.bnl.gov/mailman/listinfo/brahms-dev-lReceived on Thu Apr 1 19:57:36 2004
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