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/ ALCPG workshop U. Of Texas, Arlington, 09-11 Jan, 2003

2. ALCPG workshop, UTA, 09-jan-03 Simulation efforts at NIU Dhiman Chakraborty 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

3. ALCPG workshop, UTA, 09-jan-03 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.

4. ALCPG workshop, UTA, 09-jan-03 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.

5. ALCPG workshop, UTA, 09-jan-03 Simulation efforts at NIU Dhiman Chakraborty 5

6. ALCPG workshop, UTA, 09-jan-03 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.

7. ALCPG workshop, UTA, 09-jan-03 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.

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

9. ALCPG workshop, UTA, 09-jan-03 Simulation efforts at NIU Dhiman Chakraborty 9 Preliminary test results Sampling fractions: Passes “order-of-magnitude” sanity check, but perhaps not quite correct - being checked for bugs. SimulatorEM fracHad frac Gismo0.021870.06338 LCDG40.059360.07421

10. Total (EM+HAD) energy: 10 GeV π + Using LCDG4 with NICADD-designed detector entries :1001.0 min :0 max :16.318 mean :9.9900 rms :1.8152

11. Total HAD energy: 20 GeV π +

12. Measured energy vs n hits 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. ALCPG workshop, UTA, 09-jan-03 Simulation efforts at NIU Dhiman Chakraborty 15 SIO file contents Event header Ecal hit list Hcal hit list Tracker and muon info MC particle table

16. ALCPG workshop, UTA, 09-jan-03 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

17. ALCPG workshop, UTA, 09-jan-03 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.

18. ALCPG workshop, UTA, 09-jan-03 Simulation efforts at NIU Dhiman Chakraborty 18 Detector representation issues 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 Geometry Database (mySQL?) User Det. Sim.ReconstructionAnalysis API

19. ALCPG workshop, UTA, 09-jan-03 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.