From: Pawel Staszel (ufstasze@if.uj.edu.pl)
Date: Thu Aug 28 2003 - 15:55:27 EDT
Dear Flemming, In T4 and T5 the full drift time is about 460 tdc channels which is equivalent to 230ns. Because, the full drift length 1.1cm (=11000 microns) we have an average drift velocity of 48microns/ns. This means that with the resolution of about 120microns our timing resolution is about 3ns. This means that the seen change for worst of resolution might be due to the wider vertex. So, I will try to use TD1. Please, refer myself to the place where I could find an info. of how to use TD1 info. in a right way. I always quote a deviation of residuals from fit summed over all views - this should be close to a single plane resolution at least in x view. Assuming 120microns resolution on a single plane we have ~120/Sqrt(6) of the x position resolution on a single detection module (x1,x2,u1,u2,v1,v2) (for T3 it is 120/Sqrt(8)). Correction for u and v direction (which is 18 deg. from horizontal), does not change this result significantly. Regards Pawel. Flemming Videbaek wrote: >Dear Pawel, > >On the trigger - what was done was the inel detector were taking out of the FS trigger. On the other hand the trigger >timing certainly does not change due to this (or rather at most ~1-2 nsec). The tracks you see come from a wider vertex >and may thus have longer flight time (up to 5-8 nsec) more. Can this change your calibration's. >If this is correctone could think about adjusting the time (based on the t0 from the TD1 counters that are always present >for good FS tracks (or at least with a very high effeciency.) >I do not know enough about the DC to see if 5 nsec can change resolution.? > >I have a question for you Pawel, when you quote a resolution is this per plane, residuals in the fit, or >positionresolution >for the track ? > >Flemming > > >------------------------------------------------------ >Flemming Videbaek >Physics Department >Brookhaven National Laboratory > >tlf: 631-344-4106 >fax 631-344-1334 >e-mail: videbaek@bnl.gov > >----- Original Message ----- >From: "Pawel Staszel" <ufstasze@if.uj.edu.pl> >To: <brahms-dev-l@bnl.gov> >Sent: Wednesday, August 27, 2003 5:34 PM >Subject: Re: DC tracking calibratios - question for Pawel > > >| Hi Bjorn, >| >| Bjorn H Samset wrote: >| >| >Hi Pawel. Could you give me some DC input? >| > >| >We're about to do a runthrough of dAu localtracking, and I'm wondering >| >about the DC calibrations - are these the most recent ones? >| >/brahms/u/ufstasze/brahms/brahms_app/ps_app/dc/calib/calpar/*.dat >| > >| >>From what I see here, I'd set the calib. run to be >| >dAu: 7634 >| >pp2003: 8931 >| >Is that correct? >| > >| > >| The path is right. So far we have two different calibration files, >| namely for CalibRunNo=6418, >| and CalibRunNo=8931. The last one is probably the best option for the >| last pp running and for >| some period of dAu, but concerning the tuning parameter which we have >| right now in the db (globalTdcOffest and driftTime), 6418 should be used >| for run numbers < 8931 and 8931 for run numbers >=8931. >| >| We have a problem with calibration for runs > 8966 - the resolution is >| rather bad. Maybe it is >| connected with a comment which was put in the comment field of run # >| 8967: "changed FS trigger to be RC.TD1.H1.. no INL only RC". I'm waiting >| for a feedback from Flemming to understand the problem. >| >| >Just to be on the safe side, this is then the code I'd be using (same for >| >T4 and T5...): >| > >| > Int_t CalibRunNo = 7634; >| > >| Don't use 7634. >| >| > >| > BrDCTrackingModule* t3 = new BrDCTrackingModule("T3", "T3", kFALSE); >| > t3->UseMySql(); >| > t3->SetMode(1); >| > t3->SetAssociatedHitsMode(kTRUE); >| > >| >t3->SetCalibFile(Form("/brahms/u/ufstasze/brahms/brahms_app/ps_app/dc/calib/calpar/T3CalibRun%d.dat", >| >CalibRunNo)); >| > >| >t3->SetOffsetFile(Form("/brahms/u/ufstasze/brahms/brahms_app/ps_app/dc/calib/calpar/T3OffsetRun%d.dat", >| >CalibRunNo)); >| > t3->SetMinWidth(16); >| > t3->SetHitNumberLimit(10, 1500); >| > t3->SetVerbose(50); >| > >| > // T3 >| > BrDcRdoModule* t3Rdo = new BrDcRdoModule("T3", "T3"); >| > >| >t3Rdo->SetCalibFile(Form("/brahms/u/ufstasze/brahms/brahms_app/ps_app/dc/calib/calpar/T3CalibRun%d.dat", >| > CalibRunNo)); >| > >| >t3Rdo->SetOffsetFile(Form("/brahms/u/ufstasze/brahms/brahms_app/ps_app/dc/calib/calpar/T3OffsetRun%d.dat", >| > CalibRunNo)); >| > mainModule->AddModule(t3Rdo); >| > >| > >| >For T5, I'd set the following change: >| >t5->SetViewCombinerParams(1,1,2,0,0); >| >t5->SetHitNumberLimit(6, 1500); >| >(by looking at the code most recently used by Ian...) and maybe drop the >| >T4 Rdo module? >| > >| >Please let me know if the above is somwhow wrong, or if there's anything >| >else I should know before launching this reco. >| > >| > >| To get the right local dc tracking setup just refer to >| ProductionReduction.C on ~bramreco/reduce. >| >| >Ping :-) >| > >| >-- >| >Bjorn H. Samset Phone: 22856465/92051998 >| >PhD student, heavy ion physics Adr: Schouterrassen 6 >| >Inst. of Physics, University of Oslo 0573 Oslo >| > \|/ >| >----------------------------> -*- <----------------------------- >| > /|\ >| > >| > >| > >| > >| >| > > > >
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