LCD simulation software efforts at NIU

1. LCD simulation software efforts at NIU Dhiman Chakraborty dhiman@fnal.gov Northern Illinois University (NIU)/ Northern Illinois Center for Accelerator and Detector Development (NICADD) http://nicadd.niu.edu/ ALCPGworkshop U. Of Texas, Arlington, 09-11 Jan, 2003

2. LC detector simulation software: work in progress • Transition from GISMO to GEANT4, • Modular, flexible design towards a universal package • Standardize interfaces to offer the best of all implementations currently available for • detector geometry description • input data (event generator output) • detector simulator output Simulation efforts at NIU Dhiman Chakraborty

3. The LCDG4 detector simulation package(M. Arov, R. McIntosh, V. Zutshi, D. Chakraborty, NIU/NICADD) • A GEANT4-based simulation program • Not tied to any specific platform (ROOT/JAS/PAW) • XML description of detector geometry • Needs structural improvements for better generality • Reads input data in STDHep format • SIO/ROOT/ASCII output • S(erial)IO compatible with JAS-based analysis code • LCDG4 can write and JAS can read ROOT files • Beta release imminent • 2 known problems fixed during the NIU workshop • The plan is to merge LCDG4 and MOKKA into a single package that combines the best of both. Simulation efforts at NIU Dhiman Chakraborty

4. Decoupling the simulator from Root • LCDG4 is adapted from LCDRoot (M. Iwasaki, T. Abe), • Root internal classes replaced by STL, CLHEP, • Now a standalone simulation program, not tied to any other application/analysis environment, • I/O compatible with the SLAC/HEP.LCD library & JAS, • Root output capability is preserved as an option. Simulation efforts at NIU Dhiman Chakraborty

5. Simulation efforts at NIU Dhiman Chakraborty

6. Advantages of the SIO format • (sequential) access to very large files without overburdening memory, • Allows simultaneous writing to multiple streams, • Has built-in file compression, which is important in view of large event sizes. Simulation efforts at NIU Dhiman Chakraborty

7. Non-projective and non-rectangular cell geometries (in the digitizer) • Gismo-based simulator only allows towers of constant (Δθ,Δφ), • An entirely projective tower design is not optimal for an E-flow calorimeter, • (r,θ) range is too large for uniform scaling. • Particular non-projective and non-rectangular geometries have been simulated in LCDG4 although more work is needed to make it more general and flexible, • Projective rectangular geometries are supported just as in Gismo. Simulation efforts at NIU Dhiman Chakraborty

8. NIU Prototype Z(k) (j,k) Layer (i) (0,2) Cell (j, k) (-1,1) (1,1) φ(j) (0,0) (-1,-1) (1,-1) (0,-2) The Cell “neighborhood”

9. Preliminary test results • Sampling fractions: • Passes “order-of-magnitude” sanity check, but perhaps not quite correct - being checked for bugs. Simulation efforts at NIU Dhiman Chakraborty

10. 140 120 100 80 60 40 20 0 0 2 4 6 8 10 12 14 16 Energy, GeV Total (EM+HAD) energy: 10 GeV π+ entries : 1001.0 min : 0 max : 16.318 mean : 9.9900 rms : 1.8152 Using LCDG4 with NICADD-designed detector

11. 50 45 40 35 30 25 20 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Energy, GeV Total HAD energy: 20 GeV π+

12. Energy, GeV 18 16 14 12 10 8 6 4 2 0 5 10 15 20 25 30 35 number of hits in 1000s Measured energy vs nhits in HCal: 20 GeV π+ Shape ok, but horizontal scale is ~7x Gismo!

13. Hcal longitudinal shower profile of 10 GeV π+

14. Total energy measured in Hcal: 10 GeV π+ (1000 events)

15. SIO file contents • Event header • Ecal hit list • Hcal hit list • Tracker and muon info • MC particle table Simulation efforts at NIU Dhiman Chakraborty

16. How to check it out • http://nicadd.niu.edu/simulations/software/ • Source + binary (Linux) are available • lcdg4-bin,tar.gz and materials.tar.gz • the shell command is > lcdg4 b input_file.xml output_file.sio Detector_ID MacroFile HepEvt_File Simulation efforts at NIU Dhiman Chakraborty

17. Known problems, things to do … • Primaries absent from the MC particle table • Cause found, figuring out fundamental changes in container structures which will optimize speed will also cure this problem. • Too many hits, excess energy may be due to overcounting (?), the above procedure should fix this as well. • Geometry is hard-coded in the non-projective version. Need to combine with the projective version, make it more general and flexible. • Some more “integration”/packaging needed. Simulation efforts at NIU Dhiman Chakraborty

18. Detector representation issues User Goals • portability – easy exchange of detector models • flexibility -- easy changes in detector configuration • uniformity (universality) in detector description for comparisons and cross checks across detectors. • … Driver + API-handler layer GUI editor API Geometry Database (mySQL?) API API API Det. Sim. Reconstruction Analysis Simulation efforts at NIU Dhiman Chakraborty

19. Summary and plans • A stand-alone simulation program based on GEANT4 is ready for testing. • Order events online at http://nicadd.niu.edu/ • Has all the capabilities of Gismo, plus some more. • A few problems – being fixed. • Emphasis on the need for global integration – working with SLAC, CALICE, to combine the best of Mokka and LCDG4 into one simulation package. • Figuring out the recipe for detector geometry description is a major challenge ahead. • Start with a lightweight, flexible, functioning system. • Documentation: manuals, tutorials, FAQs, … • It’s a major undertaking – collaborator(s) wanted. Simulation efforts at NIU Dhiman Chakraborty