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Forward Tracking Plans by the Vienna iLCsoft Group

Forward Tracking Plans by the Vienna iLCsoft Group. Winfried A. Mitaroff AIDA Kick-off Meeting WP2 16 - 18 February 2011. Expertise at HEPHY Vienna. “Vienna School” of detector-related data analysis Founded in the late 1970s by Meinhard Regler at HEPHY Vienna.

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Forward Tracking Plans by the Vienna iLCsoft Group

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  1. Forward Tracking Plansby the Vienna iLCsoft Group Winfried A. Mitaroff AIDA Kick-off Meeting WP2 16 - 18 February 2011

  2. Expertise at HEPHY Vienna • “Vienna School” of detector-related data analysis • Founded in the late 1970s by Meinhard Regler at HEPHY Vienna. • Contributions to experiments since ~ mid 1980s • LEP-DELPHI, framework DELANA (f77): Local PR of FCA. Forwardtrack fit incl. VFT (Kalman), later merged with barrel for reprocessing. • LHC-CMS, framework CMSSW (C++): Track and vertex reconstruction(Kalman, pioneering DAF, GSF). Offspring: vertex reco toolkit RAVE. • Detector-independent tool LDT (MatLab) for fast simulation and trackreconstruction (Kalman). Used for optimizing ILD and CLIC detectors. • KEKB-Belle II, framework BASF 2 (C++): Track search in SVD. Trackfit in PXD-SVD-CDC (Kalman, DAF, GSF). Both are still in progress. • Dept. for Algorithms and Software Development • Headed by Rudi Frühwirth. A recent publication of general interest:A. Strandlie and R. Frühwirth, Rev.Mod.Phys. 82 (2010) 1419-1458. AIDA Kick-off Meeting WP2

  3. Sub-tasks of Work Package 2“Common Software Tools” (Coordinators: Frank Gaede and Pere Mato) • Task 2.2: “Geometry Toolkit for HEP” • Task 2.3: “Reconstruction Toolkits for HEP”(Coordinator: Frank Gaede, DESY) • Sub-task 2.3.a: “Tracking Toolkit”(Coordinator: Steven Aplin, DESY)* “Barrel Tracking”: DESY, ...* “Forward Tracking”: Santander, Valencia, Vienna • Sub-task 2.3.b: “Alignment” • Sub-task 2.3.c: “Pile-up Events” • Sub-task 2.3.d: “PFA Calorimetry” AIDA Kick-off Meeting WP2

  4. Example of a forward region • The ILD_00 detector forward layout: • Very forward region: “forward task”– 5.00 < ϑ < 11.50: only FTD measuremts. contributing,– Range of FTD 1 (2) starts where that FTD 6 (7) ends. • Intermediate region:“forward task”– 11.50 < ϑ < 25.50: complex mix of VTX + FTD + TPC,– FTD: only FTD 1 … 3, plus FTD 4 until ϑ < 16.50,– TPC: 10 pad-rows @ 11.50 … 100 pad-rows @ 25.50. • Barrel + FTD 1 only:“barrel” or “fwd.” ? • – 25.50 < ϑ < 36.70: VTX + FTD 1 + SIT + TPC. • ETD:ignored by track fitting (no more precision) • – 9.80 < ϑ < 36.90: PR link to fwd. ECAL, useful in PFA. ϑ = 900 36.70 25.50 16.50 11.50 10 padrows → 80 50 FTD 1 2 3 4 5 6 7 Pixel disks Double-sided (stereo angle) strip disks AIDA Kick-off Meeting WP2

  5. Pilot implementation for ILD • AIDA sub-task 2.3.a • Deliverable: generic toolkit for Track Reconstruction. • Timescale: spring 2011 – spring 2015 (4 years). • ILD track reconstruction • Processor in MarlinReco: wrapped legacy Fortran code,used for the 2009 LoI. Urgent need of new C++ code ! • Timescale: now – early 2012, to be used for the DBD. • Pragmatic solution • Coding for ILD may serve as a “pilot implementation”. • Experience gained will be used for the AIDA deliverable. • Next slides: ruminations on the ILD Fwd. Tracking. AIDA Kick-off Meeting WP2

  6. Forward tracking sub3-tasks • FTD geometry description, • FTD drivers in Mokka, • FTD digitizations in Marlin, • FTD stand-alone track search(very fwd. and intermediate regions, 50 < ϑ < 25.50), • TPC-supported track search(optional in intermediate region, 11.50 < ϑ < 25.50), • DAF-based final hit associations, • Precision forward track fit. • Region 25.50 < ϑ < 36.70 is “mostly barrel” (VTX, SIT, TPC) with only one FTD 1 ➯ barrel or fwd. task ? AIDA Kick-off Meeting WP2

  7. Fwd. track search strategies • Stand-alone in FTD: • This is the only possible strategy in the very forward region, • Various algorithms exist – which to chose needs careful study, • For small ϑ, hits from beamstrahlung-induced background may cause further problems (we need a reliable estimate), • Layout for optimized track resolution (e.g. strip orientation and stereo angle) not necessarily optimal for track search. • Combined TPC–FTD: • This may be an optional strategy for the intermediate region: • Inward extrapolation of tracks found by local PR in the TPC,FTD hits tested against and associated to them, • Timing problems hopefully solved by “time stamps”. • Soft hit association: • Hits may be shared among tracks, and the final association relegatedto track reconstruction based on the DAF. AIDA Kick-off Meeting WP2

  8. Forward track reconstruction • Algorithms used: • Based on the Kalman Filter, with robustification by the adaptive Deterministic Annealing Filter (DAF): • (1) Testing and updating the track hypothesis (hit associations) by identifying and removing “outliers”, and resolving ambiguous associations from the track search, • (2) Performing a precision track fit. • Special features: • Flexible track propagation in the complex intermediate region, • Energy loss of electrons modeled by the Gaussian Sum Filter (GSF) ➯ requires extension of the LCIO data model, • Magnetic field distortions by the “anti-DiD” taken into account (small “Billoir corrections” on helices, or Runge-Kutta). AIDA Kick-off Meeting WP2

  9. Open questions of the design • The user API should be common for barrel and forward tracks. • However, the implementation is suggested to be separate and complementary for the barrel and the forward regions: • Optimal track search algorithms will differ for barrel and fwd., • Internal track representations may differ (e.g. 1/pT vs. 1/P), • Coordinated independence of the two programming teams. • A small MarlinReco control processor for the required top-level steering “barrel vs. fwd. calls”, transparent to the user. • Coordination is enhanced by a common skeleton toolkit (GenFitor KalTest), and a pool of utility classes and libraries. • Both implementations will rely on common interfaces, e.g. for • Using available results from a previous track search in TPC, • Persistency by the new LCIO data model, augmented for GSF, • Interfacing to the new GEAR geometry toolkit (A. Münnich, CERN). • Clear separation of generic vs. detector-dependent functionality. AIDA Kick-off Meeting WP2

  10. Sharing of responsibilities Discussions at the ILD Software WS (DESY, July ‘10) and thereafter, consent about sharing of tasks for the new ILD tracking: • DESY Hamburg:Overall coordination and all barrel tracking: work has started. • Spain (Santander, Valencia) and HEPHY Vienna:All forward tracking, with the sub3-tasks • (1,2) FTD geometry description, drivers in Mokka: Spain, • (3) FTD digitizations: Spain with contributions by Prague, • (4) FTD stand-alone fwd. track search: Spain and Vienna, • (5) TPC-supported fwd. track search: Vienna, • (6,7) DAF-based fits, precision track fit: Vienna. Active work expected to start after this Meeting (April ‘11 ?). AIDA Kick-off Meeting WP2

  11. Manpower & funding in Vienna • Commitment: • Expect a PhD student in his/her first year, to work full-time on WP2 sub3-tasks 4–7 from spring 2011 for 1+ year; • Follow-up study of background radiation in the forward region, starting in spring 2012 (overlap with WP9.4 work); • Supervision by Winni M., backed by Rudi Frühwirth; • Work for WP9.4 from mid 2012 onwards (Thomas Bergauer). • AIDA Proposal: • Rely on 1/3 refunding for 3+ student-years, and travelling costs. • Budget crisis: • Complementary 2/3 funding by the Austrian Academy of Sci.(official AIDA partner) is in danger due to severe budget cuts ! • Fallback solution if funding fails ? Who could take over ? AIDA Kick-off Meeting WP2

  12. Thank you ! AIDA Kick-off Meeting WP2

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