Software for LCTPC Astrid M¨ unnich TPC Review DESY 4. November 2013 Astrid M¨ unnich (DESY) Software for LCTPC 1
Overview Concept: The Framework MarlinTPC Simulation Reconstruction Analysis Missing Items & Challenges Summary & Outlook Astrid M¨ unnich (DESY) Software for LCTPC 2
The Framework ILCSoft provides software packages for the linear collider community: LCIO: Common persistent data format, classes used for the TPC: TrackerRawData, TrackerData, TrackerPulse, TrackerHit, Track GEAR: Geometry description: position of modules, design of pad plane, transformation between local and global coordinates Marlin: Processor based reconstruction and analysis framework MarlinTPC: Implementation of reconstruction, analysis and tools needed for data analysis and simulation Astrid M¨ unnich (DESY) Software for LCTPC 3
MarlinTPC: The Clients Reconstruction framework for many different technologies: Pads Pixel MicroMega GEM MicroMega GEM Pixel raw data AFTER raw data ALTRO raw data Pulse Finding Pulse Finding Cluster Finding Cluster Finding Hit Finding Hit Finding Hit Finding (pad based) (pad based) (cluster based) Hits Tracking Astrid M¨ unnich (DESY) Software for LCTPC 4
MarlinTPC: The Structure The packages structure: Marlin Framework Principle: analysis calibration LCCD LCEvent digitization GEAR examples general Marlin Processor reconstruction LCEvent simulation tools tpcconddata Information about MarlinTPC: validation https://znwiki3.ifh.de/MarlinTPC/MarlinTPC > 150 processors svn repository: ≈ 40 developer branches https://svnsrv.desy.de/desy/marlintpc/ BUT: only < 10 active Astrid M¨ unnich (DESY) Software for LCTPC 5
Simulation within MarlinTPC Different simulation approaches with different detail level: Simple Digitisation Electron Cloud Simulation Primary Electron Simulation Generator Particle Geant4 Hit Geant4 Hit Ionisation Ionisation Primary Ions Electron Cloud Primary Electrons E−Field Calculator B−Field Electrical Field Smearing Drift and Diffusion incl. B−Field Distortions Drift and Diffusion Drift and Diffusion incl. E−Field Distortions Drift and Diffusion Drifted Cloud Drifted Electrons Amplification Amplification Backdrifting Ions Charge in Voxels Amplified Cloud Amplified Electrons Electronics TPCRawData Simulation for amplification and resistive anode with MicroMegas is missing. Astrid M¨ unnich (DESY) Software for LCTPC 6
Examples: Electron Cloud Simulation Simulation of laser calibration system Photodots on cathode Tool to measure field distortions 4.270e+02 3.920e+02 3.531e+02 3.142e+02 2.753e+02 2.364e+02 1.976e+02 1.587e+02 1.198e+02 8.089e+01 4.200e+01 Overflows Underflows Astrid M¨ unnich (DESY) Software for LCTPC 7
Examples: Primary Electron Simualation Particle ID 10 muons 9 electrons Simulation of small prototypes to protons 8 kaons verify simulation pions 7 dE/dx [keV/cm] 6 Use simulation for large ILC TPC 5 4 Study e.g. dE / dx or ion back flow 3 2 1 0 1 0.1 1 10 100 simulation P5 particle momentum [GeV] measurement P5 single point resolution in x [mm] simulation TDR 0.8 Ion back flow 500 BX measurement TDR 0.6 0.4 0.2 0 0 50 100 150 200 250 drift distance [mm] Astrid M¨ unnich (DESY) Software for LCTPC 8
Field Simulation CST ➋ : Simulation of field configurations for a given geometry, e.g. a readout module: Garfield ++ : Simulation of movement and other processes like amplification of charge carriers in electric and magnetic fields. Astrid M¨ unnich (DESY) Software for LCTPC 9
Reconstruction Task: Provide the tools to get from the raw data to a track. Do that for all the different applications: GEMs with pads MicroMegas with pads GEMs with pixel MicroMegas with pixel Simulation Cathode laser dots ... Goal: Use as many common tools as possible. Provide consistent methods and concepts. Astrid M¨ unnich (DESY) Software for LCTPC 10
Reconstruction Example: Step 1 The first step is a pre-reconstruction: Provide information from data base 1 TrackerRawData Reconstruct pulses on each channel 2 TrackerRawDataToDataConverter Map hardware channel to GEAR pads TrackerData 3 Reconstruct 3D space points PulseFinder 4 TrackerPulse Tracking: Finding and Fitting 5 Obtain calibration factor to transform ChannelMapping 6 ADC counts to primary electrons RowBasedHitFinder Now determine: TrackerHit Pulse time cut off according to cathode Pulse time shift according to anode TrackFinder + Fitter position Track Other calibration info or corrections ADC2PrimaryElectron Fill conditions data base: drift velocity, diffusion, charge conversion etc... Astrid M¨ unnich (DESY) Software for LCTPC 11
Reconstruction Example: Step 2 RawDataCutter TrackerRawData TrackerRawDataToDataConverter TrackerData Apply timing cut 1 Apply time offset TimeShiftCorrection 2 Apply correct drift velocity 3 PulseFinder Apply charge conversion 4 TrackerPulse during hit finding ChannelMapping Correct time offset of RCU 5 Do the tracking again 6 RowBasedHitFinder TrackerHit Calculate correction for 7 field distortions TrackFinder + Fitter Track DistortionAnalysis Astrid M¨ unnich (DESY) Software for LCTPC 12
Reconstruction Example: Step 3 Correct distortions: Move 1 hits accordingly along row and along z Repeat tracking 2 Similar procedure for all module technologies. Small difference between GEMs and MicroMegas for pulse and hit finding, some due to technology, some to electronics. Fundamentally different between pad and pixel readout up to hit level. Astrid M¨ unnich (DESY) Software for LCTPC 13
Testbeam Data on the Grid Storage for raw data and converted LCIO data for all groups: srm://dcache-se-desy.desy.de/pnfs/desy.de/ilc/tpc/ year description/comments electronics RAW avail. LCIO avail. 2010 MicroMegas T2K NO NO 2010 3 Asian GEM ALTRO YES NO 2010 Octopuce (8 Ingrids) Timepix+Muros NO NO 2011 DESY GridGEM ALTRO YES YES 2012 6 MicroMegas int. AFTER YES YES 2012 DESY GridGEM ALTRO YES YES 2012 Asian GEM ALTRO YES YES 2013 7 MicroMegas int. AFTER YES YES 2013 DESY GridGEM ALTRO YES YES LCIO format provides the basis to exchange data! Astrid M¨ unnich (DESY) Software for LCTPC 14
Conditions Data LCCD: The L inear C ollider C onditions D ata toolkit User-defined data classes can be stored in LCIO files or a data base. A Marlin processor provides this information during run-time: Channel mapping Channel quality Pedestals v drift + diffusion Gas conditions E-field settings B-field settings HV settings Field maps Electronics information Calibration Conditions data base available at DESY: lctpcconddb01.desy.de Astrid M¨ unnich (DESY) Software for LCTPC 15
Analysis Task: Evaluate performance of LP modules Single point resolution Hit efficiency Data quality Momentum resolution Needs: In order to produce comparable results Common analysis code Rules and conventions Common cuts Use the same tools → recent progress made, several new analysis processors for common use in the last 3 weeks! Astrid M¨ unnich (DESY) Software for LCTPC 16
Missing Items & Challenges Reconstruction: Correction of over-range pulse and dead channel in hits. Correction: Correct field distortion, ideally with a well understood model and not data driven. Calibration: Calibration of electronics and gain uniformity still outstanding. Alignment: Disentangle real geometric misalignment of modules from other effects like distortions. Geometry description needs to able to represent misalignment. Tracking needs to able to handle misalignment. Astrid M¨ unnich (DESY) Software for LCTPC 17
Summary A lot of progress has been made within the last 2 years: Simulation: Various detailed simulation chains available within MarlinTPC. External programs are used to simulate electrostatic and magnetic field maps. Reconstruction: Full reconstruction chain available for all technologies. Calibration and correction procedures are starting to develop based on recent testbeam campaigns. Effort to use as much code and tools in common as possible has started again. Analysis: Common rules and tools have been defined. A selection of plots has been agreed on. Astrid M¨ unnich (DESY) Software for LCTPC 18
Outlook Tracking Evaluate and compare different available packages Solve tracking issues for pixel readout Corrections Better non data driven correction method for field distortions. Alignment Gain experience with Millepede II mainly for alignment studies, but it can also be used to determine any parameter influencing the position measurement Simulation Readout module with gating grid Continue with simulation of field distortions Continue ion back flow studies and calculations Detailed simulation for MicroMegas dE/dx: Requires good calibration also of the gain stability and homogeneity Momentum Resolution: External reference is needed. Would also be useful for distortion studies. Astrid M¨ unnich (DESY) Software for LCTPC 19
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