LCD simulation software efforts at NIU Dhiman Chakraborty [email protected] Northern Illinois...
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Transcript of LCD simulation software efforts at NIU Dhiman Chakraborty [email protected] Northern Illinois...
LCD simulation software efforts at NIU
Dhiman [email protected]
Northern Illinois University (NIU)/ Northern Illinois Center for Accelerator
and Detector Development (NICADD)
http://nicadd.niu.edu/
ALCPG workshopU. Of Texas, Arlington, 09-11 Jan, 2003
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
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.
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.
ALCPG workshop, UTA, 09-jan-03
Simulation efforts at NIU Dhiman Chakraborty
5
O rg an iza tio n o f L CD G 4 p a cka geC la sse s m arke d in g ree n a re n e w o r rew ritten
HADCallorimeterEM Callorimeter
TrackerVXD etc.
XYZtoID classInitialization
Required for futureSpecialization of the detector
XML2G4DetConstExtracts the info
about the dimmentions ofthe detector
SIO record constructor
Primary Detector Construction
STDHEP inputUnder construction
PrimaryGeneratorActionMain Physics content
XYZtoID convertionProdices the HitID
HAD HitsEM HitsMU Hits
etc.
SIO record fillThe final output stream
EventAction TrackerActionStepingAction
(MCpart Mannager)
LCDG4The Main Driver
XML parserReads in the detector description
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.
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.
(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
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.
Simulator EM frac Had frac
Gismo 0.02187 0.06338
LCDG4 0.05936 0.07421
Total (EM+HAD) energy: 10 GeV π+
Using LCDG4 with NICADD-designed detector
Energy, GeV
0 2 4 6 8 10 12 14 160
20
40
60
80
100
120
140 entries : 1001.0 min : 0 max : 16.318 mean : 9.9900 rms : 1.8152
Energy, GeV
1 2 3 4 5 6 7 8 9 10 11 12 13 14 1505
101520253035404550
Total HAD energy: 20 GeV π+
number of hits in 1000s
Energy, GeV
0 5 10 15 20 25 30 35
2468
1012141618
Measured energy vs nhits in HCal: 20 GeV π+
Shape ok, but horizontal scale is ~7x Gismo!
Hcal longitudinal shower profile of 10 GeV π+
Total energy measured in Hcal: 10 GeV π+ (1000 events)
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
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
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.
ALCPG workshop, UTA, 09-jan-03
Simulation efforts at NIU Dhiman Chakraborty
18
Detector representation issuesGoals
• 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
GeometryDatabase(mySQL?)
User
Det. Sim. Reconstruction Analysis
API API API
API
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.