Testbeams for Simulation Norman Graf ECFA LC Workshop, Durham September 2, 2004

Problem Statement Primary goal for testbeam is to validate detector technology. However, since we are designing detectors based on simulation studies, we also need to validate the simulations. GEANT3 offered relatively few options for modeling hadronic showers. TB data-simulation discrepancies accepted. Used primarily for energy resolution.

Geant4 hadronic shower models. GEANT4 has extensive set of hadronic shower models, from which we would like to select. Several experiments have compared testbeam data with Geant4 predictions. However, used to characterize existing designs, not to design new detectors. “Particle Flow”, or imaging calorimeter, places much more stringent requirements on simulation. Cottage industry to run all available sets to demonstrate dispersion. See talks in simulation session.

Feedback from Testbeam Would like input from testbeam to provide guidance not only in selecting from existing models, but to improve existing models. Would like to see as broad a spectrum of particle type and momentum as possible. Emphasis on lower energies. Kaons needed! Detailed longitudinal and transverse shower shapes. Time evolution of shower if possible.

Physics Lists for LC Provide a “standard” Geant4 physics list to be used in study of LC detectors Make the list easy to use and understand Keep it up-to-date as new models become available Validate as test beam data becomes available Include it in LC Geant4 example (Makoto Asai)

Physics List Design Provide only one list everyone can use Specialized lists could be added later Avoid hadronic list libraries These are nice, but too general and somewhat involved Write out a “long-hand” physics list Derived from G4VModularPhysicsList Everything contained in 12 files Easy to see what processes/models are used and how they are invoked

Justification of Model Choices: Below 20 GeV Between 10 and 20 GeV, only one model available: LEP Below 10 GeV, three models to choose from: Low energy parameterized (LEP) : for all particles Bertini cascade: for p, p, n only Binary cascade: for p, p, n only Pion production reactions clearly eliminate LEP Bertini and Binary equally good, Bertini 8x faster So LEP plus Bertini cascade required in list

Maintenance and Use Dennis Wright (SLAC) developing and maintaining. Physics list will be maintained in FreeHEP CVS Anyone can get it: cvs -d :pserver:anonymous@cvs.freehep.org:/cvs/lcd LCPhys Better models, bug fixes will be included as available Questions, problems to dwright@slac.stanford.edu

TB Simulations Detector geometries fairly straightforward, but require ability to define all parameters as realistically as possible. Will need commensurate simplified geometries for full detector simulations. TBMokka requires new driver for each setup. Inefficient, prone to error, hard to maintain (copy/paste). Need revision of Mokka concept. DESY, NICADD, SLAC collaborating on development. Need requirements from users!