Re: brag and acceptances

From: Flemming Videbaek (videbaek@sgs1.hirg.bnl.gov)
Date: Thu Jul 04 2002 - 14:12:39 EDT

  • Next message: Djamel Ouerdane: "Re: brag and acceptances"

    Djamel,
    
    Do you have any of the messages kept anywhere - it does report what
    detector.
    If so send me the info.
    I do not recall seeing any with the 8 deg stuff that I looked into late last
    week
    So the advice depends a liuttle what was the actual message. It is possible
    to get the message
    under other conditions e.g. if a thin detectors set up to deal with high
    precesiion gets hit with a very
    large energy one can get an overflow - so noit all of these have to be bad.
    
    Flemming
    
    
    ------------------------------------------------------
    Flemming Videbaek
    Physics Department
    Brookhaven National Laboratory
    
    tlf: 631-344-4106
    fax 631-344-1334
    e-mail: videbaek@bnl.gov
    ----- Original Message -----
    From: "Djamel Ouerdane" <ouerdane@nbi.dk>
    To: "devlist" <brahms-dev-l@bnl.gov>
    Sent: Thursday, July 04, 2002 11:23 AM
    Subject: Re: brag and acceptances
    
    
    > Hi Flemming,
    >
    > What does that imply for all the simulations done so far ?
    > I remember having seen this GSAHIT message billions of times in the FS
    > simulations. Are the cdat files created so far for the FS good enough ?
    >
    >
    > Djam
    >
    >
    > On Thu, 4 Jul 2002, Flemming Videbaek wrote:
    >
    > > Djam observed and reported a problem in the acceptance calculation using
    brag for 30 deg. That hits in T2 looked strange.
    > > I checked it this morning and observed that geant gave an error message
    when being run
    > >
    > >  ***** GSAHIT OVERFLOW WHEN IUSET= T2   IUDET= T2PR HITS(
    1)=-0.4113410E+03 ORIG=  0.4000000E+03 FACT=  0.1000000E+04
    > >  ***** GSAHIT OVERFLOW WHEN IUSET= T2   IUDET= T2PR HITS(
    4)=-0.4129992E+03 ORIG=  0.4000000E+03 FACT=  0.1000000E+04
    > >
    > > This is the clue - the global xhits are more negative than the orgin for
    the hit in that variable. Since hits are stored (global) inside
    > > geant as hitval= (x + origin)*fact as integer the wrong global value is
    stored.
    > >
    > > See the cern geant web pages fro more on hits (and nearby pages)
    > > http://wwwinfo.cern.ch/asdoc/geant_html3/node148.html
    > >
    > > The origins for t2,tof2, c1 as well for t3,t4 t5 were changed and
    commited (FFS up to 30 deg BFS to~20deg - which it cannot do physically)
    > > The version is now 1.1.14 and has been installed in opt/brahms/new.
    > >
    > > Lesson to be learned
    > > a) Though much of BRAG has been extensively tested there can still be
    problems
    > > b) In case of problems check log-output for possible errors that might
    be a clue.
    > > c) As was done- communicate problems
    > >
    > >
    > >
    > > Thanks to Pawel for posting tracking effeciencies for the FS.
    > >
    > > This bring up a point- I would think that part of the effeciencies say
    determined for T1 (and T1) is due to
    > > bad and non-instrumented pads. If this is the case I think it
       --incorrect -- in the geometric acceptance to
    > > take into account dead and non instrumented pads as I believe it is done
    in the BrGeanToTpcTrackCandidate.
    > > If so we should either change the geometric acceptance-calculation, or
    take the effect of of the 'experimental
    > > tracking eff' which seems at best difficult.
    > >
    > > Comments to this?
    > >
    > >
    > > regards from a hot and steamy Long Island
    > >
    > > Flemming
    > >
    > >
    > >
    > > ------------------------------------------------------
    > > Flemming Videbaek
    > > Physics Department
    > > Brookhaven National Laboratory
    > >
    > > tlf: 631-344-4106
    > > fax 631-344-1334
    > > e-mail: videbaek@bnl.gov
    > >
    >
    > --
    > Djamel Ouerdane ------------------------------------------o
    > |  Niels Bohr Institute      |  Home:                     |
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    > |                  ouerdane@nbi.dk                        |
    > o---------------------------------------------------------o
    >
    



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