Re: dEdx for tracks in the tpcs

From: Jens Ivar Jordre (jens@fi.uib.no)
Date: Mon Nov 13 2000 - 10:19:22 EST

  • Next message: Peter H. L. Christiansen: "Re: dEdx for tracks in the tpcs"

    On Mon, 13 Nov 2000, Claus O. E. Jorgensen wrote:
    
    >
    > Hello everybody
    >
    > I would like to start a discussion on how to get
    > dEdx information for the local tracks. Right now
    > the only way to do it is to get the BrDetectorHits
    > and look through all the BrTPCHitClusters to see
    > which hit matches which cluster and then get the
    > energy from the cluster. As I see it we have 3
    > options:
    >
    > 1) Keep it the way it is.
    >
    > 2) Let the BrDetectorHit have an Float_t dEdx
    > member and corresponding get and set methods.
    >
    > 3) Let the BrDetectorHit have a void pointer to
    > the BrTPCHitCluster (or the BrDCCluster) and
    > corresponding get and set methods
    > (void* GetMotherCluster() and SetMotherCluster(*void).
    >
    > As I see it the latter is the best solution. It
    > will make it easy to get the energy, and we'll
    > avoid having a not-defined dEdx for detector hits in
    > the DCs (these detectors don't measure the energy,
    > as far as I'm informed).
    >
    > Any comments?
    
    Here comes the first one.
    
    I agree with you. The 3rd approach resembles what is implemented for
    tracks, where BrDetectorTrack has a pointer to its mother BrLocalTrack.
    
    Also present in the current version of BRAT is ID inheritage, i.e. new
    instances of BrDetectorHit inherit the ID from their mother
    BrTPCHitCluster, which again inherits ID from its mother BrTPCCluster.
    This may be what you refer to as matching hits and clusters. But it is
    arather time consuming process to match ID compared to getting the mother
    data structure from a pointer. I therefore support your view.
    
    JI
    
    ---
    Jens Ivar Jřrdre, Dep. of Phys., Allégt. 55, N-5007 BERGEN, NORWAY
    room 521, e-mail: JensIvar.Jordre@fi.uib.no, phone: (+47) 55 58 27 92
    



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