The CMS Simulation Validation Suite

1. The CMS Simulation Validation Suite V. Daniel Elvira (Fermilab) for the CMS Collaboration V. Daniel Elvira

2. Detector Simulation Generation Digitization Reconstruction Pool HepMC data file Pool SimHit data file Pool Digi data file Simulation Software in CMS Generation – MC truth information from particle gun or physics generator about vertices and particles. Stored in HepMC format. Detector Simulation – Hit objects with timing, position, energy loss information. Based on the Geant4 tool kit. Digitization – Constructs Digi objects which include realistic modeling of electronic signal. Reconstruction – Physics Objects: vertices, photons, e, m, jets,…… V. Daniel Elvira

3. Physics Software Validation • Elements to validate: • Geometry description & magnetic field map • Physics of EM and Had showers in Geant4 - hits • Digitization Model - digis • Reconstruction Algorithms – physics objects For absolute validation: Use visualization tools, TB experiments, reference plots The Simulation Validation Suite (SVS) validates in an automated way each new release of the CMS simulation software, comparing values of quantities related to geometry, field, hits with reference values from a previously (absolutely) validated version. Expansion to “Physics Software Validation Suite” including digis, reco ……in progress V. Daniel Elvira

4. CMS Detector Systems SVS modular structure follows the detector sub-systems Solenoid Magnet: 4 Tesla Field Muon System Electromagnetic Calorimeter (Ecal) Hadronic Calorimeter (Hcal) Silicon Tracker 22 m long & 15 m in diameter More than 1 Million Geometrical volumes V. Daniel Elvira

5. SVS: General Description OVAL: testing tool created by CMS to detect changes in software behavior. Used as the SVS integration tool. It executes scripts and shell commands to control the suite execution and perform comparison tests. Pre-generated samples: single particles, pp physics (Pool files, ROOT browsable, HepMC format) SVS software sub-systems (dedicated simulation packages) Validation branch (Pool files, ROOT browsable) SimG4TrackerValidation SimG4EcalValidation SimG4HcalValidation SimG4MuonValidation SimG4GeomValidation SimG4FieldValidation SimG4GlobalValidation OVAL Configuration file: commands, tolerance values On the fly analysis: basic G4 objects processed into information to construct validation quantities. V. Daniel Elvira

6. SVS: General Description (II) Validation branch (Pool files, ROOT browsable) ROOT Analysis Macros OVAL • Construct Validation • Quantities • Create/fill histograms • Read reference files • Perform Validation Tests: • c2 or Kolmogorov-Smirnov Reference Histograms from previous version (ROOT file) Configuration file: commands, tolerance values (LCG PI Statistics Testing toolkit, or ROOT) One or more tests per sub-detector: low/high level quantities, different sub-detector components. List of differences for quantities not passing the tests (ASCII files) Results are reviewed by system experts: approve & release, or investigate problems V. Daniel Elvira

7. Tracker Validation Tracking system: Silicon Strip Tracker - Tracker Inner Barrel (TIB), Tracker Outer Barrel (TOB), Tracker Inner Disks (TID) and Tracker End Cap (TEC) Pixel Detector - Pixel Barrel and Pixel End Cap. Sample: Single muons, electrons or pions with pT =15 GeV in 12 bins of in the range -3<h<3 (1,500 events) Identical Distributions Reference Distribution Validation Quantities: Energy deposition Distribution of track entry and exit points Number of hits Time of flight,……, etc Current Distribution V. Daniel Elvira

8. Ecal Validation Electromagnetic Calorimeters:Ecal Barrel – Ecal Endcap (crystals) Preshower (Si/lead) Low Level Test: Single 30 GeV photons (2,000 events) • h vs f hit occupancy in crystals • E1, E2x2, E3x3, E4x4, E5x5 depositions • E1/E4, E4/E9, …, E9/E25 ratios • Percent of E in Barrel, Endcap, Preshower • Longitudinal shower development High Level Test: Single 10GeV, 20GeV, 30GeV, 40GeV, 50GeV(2,000 events) • E25 resolution vs the incident energy • Longitudinal shower development vs energy • Coefficient of Lead absorption vs incident • energy (preshower) V. Daniel Elvira

9. Ecal Validation (II) V. Daniel Elvira

10. Hcal Validation Hadronic Calorimeters:Hcal Barrel – Hcal Endcap (copper/scint.) Hcal Forward (steel/quartz fibers) Single 50 GeV pions (1,000 events) • E depositions in each HB layer • Time dist. of Hit energy in 7x7 tower matrix • Number of hits in Ecal and Hcal • Energy in 1x1, 3x3, 5x5 tower matrices • Total energy in Hcal • Total energy in long fibers (HF) • Total energy in short fibers (HF) • ………… Time distribution in 7x7 tower matrix Layer 0 V. Daniel Elvira

11. Muon Validation Muon System: Drift Tubes (DT) in central region. Cathode Strip Chambers (CSC) in forward region. Resistive Plate Chambers (RPC) in both for trigger. Single 100 GeV muons (1,000 events) E lost by m in full CMS detector For 100 GeV m, <E>~8 GeV For each muon: • Energy lost • Deviation in position • Deviation in angle (deg) • Number of tracking steps For each type of muon process (ionization, bremsstrahlung, e+e− production, muon nuclear interaction, decay and capture): • Energy of secondary particles • Angle of secondary track with respect to primary muon track V. Daniel Elvira

12. Geometry Validation Computes the number of volumes and materials and the total number of radiation lengths through the CMS detector. Sample 1,000 m of E=10 TeV and random h, f (= neutral geantinos since physics/field off) Validation Quantities • The geometry summary: number of different materials, number logical volumes, physical volumes. • The number of radiation lengths after traversing the full detector. Material Budget (ROOT tree, histos, or ascii file) For each Geant4 step of each muon: • Accumulated track length, volume name, volume copy number, accumulated material budget (Number of radiation lengths), material radiation length. At the end of track: • Accumulated material budget. V. Daniel Elvira

13. Field Validation Checks the tracking in the CMS magnetic field. The test compares the deviation at the end of the track in position and direction. Sample 400 single muon events in four groups of 100 events with different energies: 1, 10, 100, 1000 GeV. The muons behaves as charged geantinos (physics is off). Validation Quantities Change in track angle, momentum, kinetic energy. V. Daniel Elvira

14. Global Validation Sub-system packages: dedicated validation tests for individual sub-systems. Geometry sub-set, field off. Global package: validates entire detector with real field, using pp physics samples. For example, min-bias. • Monte Carlo • Number of vertices from Geant4 • Number of tracks from Geant4 • Number generated particles • Position (x,y,z) of each Geant4 vertex • pT of each Geant4 track • Energy of each Geant4 track 2. Electromagnetic Calorimeter Number of Ecal hits Energy of each Ecal hit Time of flight for each Ecal hit Global h of each Ecal hit Global f of each Ecal hit Number of preshower Hits Energy of each preshower hit Time of flight for each preshower hit Global h of each preshower hit Global f of each preshower hit V. Daniel Elvira

15. Global Validation (II) 3. Hadronic Calorimeter Number of hits Energy of each hit Time of flight for each hit Global h of each hit Global f of each hit 4. Tracker Number of Pixel hits Global h of each Pixel hit Global f of each Pixel hit Time of flight of forward Pixel hits Time of flight of barrel Pixel hits Global R of barrel Pixel hits Global Z of forward Pixel hits Number of Silicon hits Global h of each Silicon hit Global f of each Silicon hit Time of flight of forward Silicon hits Time of flight of barrel Silicon hits Global R of barrel Silicon hits Global Z of forward Silicon hits 5. Muon Number of hits Global h of hits Global f of hits Time of flight for DT hits Global R of DT hits Time of flight for CSC hits Global Z of CSC hits Time of flight for RPC barrel hits Global R of RPC barrel hits Time of flight for RPC forward hits Global Z of RPC barrel hits V. Daniel Elvira

16. Summary & Outlook CMS simulation validation suite for hit derived quantities is operational – being ported to the CMSSW framework • Iterate on validation quantities • Optimize sample types, size, tune tolerance values In progress: • Expand Physics Validation Suite to include Digis (pulse • shape, pedestals, gains) In the future: • Incorporate reconstructed physics objects: jets, e, g, m V. Daniel Elvira