From: Gloria Corti
Sent: Thursday, September 23, 2004 5:40 PM
To: Florence Ranjard; Patrick Robbe; Witold Pokorski; Sajan Easo
Cc: Philippe Charpentier; Gloria Corti
Subject: Draft answer for GEANT4 Technical Forum in Catania 

Dear all,

  as you can see Albert De Roeck is asking for some specific information from us for the Geant4 Technical Forum.

  I append my draft answer, please let me know if you have comments/suggestions otherwise I will send it to him tomorrow morning.

  New requirement:
  - The list of the created processes is printed at the beginning of a job.
    Although very usefull for development and verification this printing 
    should be under user control (in an easy way), for example to be able 
    to switch it off during production of many events.

  Past requirements:
  - 0301) Robustness of G4 and improved diagonostics to give more handels to solve problems
          Originator: (LHC experiments) 
          Description: " The LHC experiments CMS and LHCb are entering production now. Occasional
          crashes are seen in simulations of files containing several hundered events. These 
          problems will have to be tackled and removed. Additional information given/printed 
          during the abort will help to localize the problem. " 

    This is beeing met (when new cases appear, the authors are helpful in introducing the
    corresponding diagnostic)
 
  - 0308) Creating a new particle 
          Originator: LHCb (G. Corti) 
          Description: The possibility to assign a new track ID (creating new particle) to a hadron
          undergoing inelastic scattering, in all physics lists, and steerable from the physics 
          lists. The choice should be under user control since it depends on specific studies. This
          is necessary to understand the behaviour of the tracking for example where if the leading
          outgoing particle has very different kinematic from the incoming particle it can be 
          misleading [to reconstruction programs to see this] as a single particle. " 
          In cases where different behaviors of a model are a priori possible (for instance the
          desired changing or not changing the track ID for pions undergoing inelastic scattering),
          the default behaviour should be clearly stated and easily switchable by the user. 

    This is now controllable via an environment variable in Geant4 6.2

  - 0309) Provide documentation on the technical aspects of all available physics processes 
          Originator: LHCb (G. Corti) 
          Description: " All available physics processes, models, cross-sections, etc., should
          provide documentation of the technical aspects of the implementation: details of the
          expected behaviour of a model should be provided (for example how incoming and outgoing
          particles are handled). This applies to both hadronic and electromagnetic processes. " 
    
    This I do not know what status is in. Clearly this is twofold: describing the algorithm that
    implements a model will require quite a bit of work to be documented but it would also be very
    useful to have a "How to", i.e. how do I use a piece of code, can I steer it, if yes how.

    To give an example, I would like to find easily in the documentation that leading particles
    can be killed by the user in inelastic scattering by setting the "such and such" environment
    variable.
 
    This brings me to a comment not a requirements, I have sometimes difficulty in finding
    the information I look for in the Geant4 web page.

   

-----Original Message-----
From: Albert De Roeck [mailto:deroeck@mail.cern.ch] 
Sent: Wednesday, September 22, 2004 5:14 PM
To: Gloria Corti
Subject: GEANT4 Technical Forum in Catania 





Dear Gloria

Does LHCb have contributiosn to the Technical Forum during the Geant4 workshop in Catania (4/10)? It would be useful to have the list before so G4 can already think of it. Also it would be useful to let me know which requirments from LHCb from previous meetings have been met/not met...

Thanks, Albert

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