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Calorimeter Simulation Infrastructure

Calorimeter Simulation Infrastructure. Norman Graf Arlington ‘03. Detector Issues. Current simulations are good enough for many studies, but room for improvement. Need more detailed/realistic subdetector designs. Current detectors are floating cylinders!

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Calorimeter Simulation Infrastructure

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  1. Calorimeter Simulation Infrastructure Norman Graf Arlington ‘03

  2. Detector Issues • Current simulations are good enough for many studies, but room for improvement. • Need more detailed/realistic subdetector designs. • Current detectors are floating cylinders! • Luminosity monitors and masks neglected. • Fairly simple absorber/readout sandwich. • Only projective tower geometry supported. • Subdetector integration needs attention.

  3. GEANT4 • Release 5.0 out in December 2002. • Default Physics Process Lists are available. • Patches & upgrades to hadronic models. • SLAC installation includes GEISHA fixes. • Working on support for more complicated geometries. Evaluating GDML as replacement for existing XML. • T. Abe working on TGeom interface. • see talk in simulation session

  4. GEANT4 cooperation • Working with European colleagues to define common elements. • Active work on a common simulation output format (LCIO talk by T. Johnson). • Discussing geometry packages. • Looking for best aspects of current implementations • flexibility of LCD system vs detail of Mokka

  5. Detector Models • Our Calorimeter designs need work! • SD has mistake in gap between EM & HAD. • replace with strongback followed by readout. • LD needs a hadronic calorimeter! • First pass T detector to allow some comparisons to TESLA studies. • Decouple algorithm from detector. • Need work on far forward region! • Luminosity monitors & instrumented masks! • What is effect of beam crossing angle!

  6. BDS Simulation (GEANT3)

  7. BDS in GEANT4 • Full JLC BDS implemented in G4 by Tokyo group (M. Iwasaki). • Parses machine decks to create geometries. • Incorporates transport code from G. Blair. • Fruitful collaboration with T. Maruyama at ISG at KEK in December. • Look forward to full incorporation to allow detailed studies of far forward calorimetry.

  8. Reconstruction & Analysis • Huge increase in the number of analyses since the Chicago meeting. • See all the following talks. • Energy flow framework and object definitions evolving. • e.g. electron and muon ID. • Full reconstruction analyses starting. • CellsClusterscluster IDEFOanalysis • Tracks+Cells  EFOanalysis • Challenge is to accommodate disparate packages into common framework.

  9. Energy Flow • Would still like to see “smoking gun” analysis which clearly demonstrates that EFlow calorimetry is necessary. • Infrastructure to allow ganging of cells at analysis level available. • systematic segmentation studies • Would like to see dependencies on B and R. • Developing ~fast simulation package to allow fast prototyping of designs. • Crystals anyone?

  10. Backgrounds • Essential that detector design be robust against machine backgrounds. • Crucial to undertake physics studies in the correct context of irreducible physics backgrounds. • Can no longer simply float kT to get 2 jets! • Correctly simulate and overlay backgrounds on signal, event-by-event.

  11. Machine backgrounds • e+e- pairs from beam-beam interactions (T. Maruyama) • Generated large samples of events, simulated in LD and SD • Have added beam train’s worth to some signal events, started analyses. • Muons from collimator halo (L. Keller) • Event samples generated • Will be simulated and available for overlay soon.

  12. Underlying Physics Processes • Dominant background due to hadrons resulting from beam- and brems-strahlung photons. • Extensively studied at LEPII, particularly by OPAL. • Event generators usually considered: • PHOJET • PYTHIA • HERWIG

  13.  Generators • Latest version of PYTHIA includes improved support for  processes. • Use CIRCE to provide input  spectrum. • PYTHIA allows event-by-event specification of cms energy. • Generate inclusive  processes. • Large samples of events have been simulated with SD and LD. • Good enough for first pass analyses.

  14. Testbeam Support • Working on GEANT4 package to support generic testbeam setups. • Flexible geometry setup, hits, digitization. • AIDA Interface for analysis. • Aid in design of R&D prototypes. • Depth, lateral extent, etc. • Study thresholds, ADC bits, dead channels, etc. • Useful for analysis of TB data.

  15. Summary • We need to improve the calorimeter designs by making them more realistic. • Far-forward calorimetry missing! • Tools are available to study backgrounds. • Many reconstruction & analysis efforts ongoing, challenge is to integrate them into common framework. • Many projects ongoing, plenty of places to plug in and contribute!

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