Intelligent

1. Intelligent Detector Design Norman Graf (SLAC) SuperB computing mini-Workshop Pearl Harbor Day, 2007

2. Linear Collider Detector Environment • Detectors designed to exploit the physics discovery potential of e+e- collisions at s ~ 1TeV. • Perform precision measurements of complex final states with well-defined initial state: • Tunable energy • Known quantum numbers & e─ , e+,  polarization • Possibilities for  , e─ ,e─ e─ • Very small interaction region • Momentum constraints (modulo beam & bremsstrahlung)

3. LCD Simulation Mission Statement • Provide full simulation capabilities for Linear Collider physics program: • Physics simulations • Detector designs • Reconstruction and analysis • Need flexibility for: • New detector geometries/technologies • Different reconstruction algorithms • Limited resources demand efficient solutions, focused effort.

4. Overview: Goals • Facilitate contribution from physicists in different locations with various amounts of time available. • Use standard data formats, when possible. • Provide a general-purpose framework for physics software development. • Develop a suite of reconstruction and analysis algorithms and sample codes. • Simulate benchmark physics processes on different full detector designs.

5. Fast Detector Response Simulation • Covariantly smear tracks with matrices derived from geometry, materials and point resolution using Billoir’s formulation. http://www.slac.stanford.edu/~schumm/lcdtrk • Derivative of TRKERR. • Provides smeared tracks with full covariance matrix.

6. lelaps • Fast detector response package. • Handles decays in flight, multiple scattering and energy loss in trackers. • Parameterizes particle showers in calorimeters. • Produces lcio data at the hit level. • Uses runtime geometry (compact.xml  godl). • An excellent tool for designing tracking detectors! http://lelaps.freehep.org/index.html

7. Lelaps: Decays, dE/dx, MCS Ω-→ Ξ0π- Ξ0 → Λπ0 Λ → p π- π0 → γ γas simulated by Lelaps for the LDC model. gamma conversion as simulated by Lelaps for the LDC model. Note energy loss of electron.

8. Detector Design (GEANT 4) • Need to be able to flexibly, but believably simulate the detector response for various designs. • GEANT is the de facto standard for HEP physics simulations. • Use runtime configurable detector geometries • Write out “generic” hits to digitize later.

9. Full Detector Response Simulation • Use Geant4 toolkit to describe interaction of particles with matter. • Thin layer of LC-specific C++ provides access to: • Event Generator input ( binary stdhep format ) • Detector Geometry description ( XML ) • Detector Hits ( LCIO ) • Geometries fully described at run-time! • In principle, as fully detailed as desired. • In practice, will explore detector variations with simplified approximations.

10. MC Event (stdhep) Raw Event (lcio) slic Geometry (lcdd) Compact Geometry Description (compact.xml) Reconstruction, Visualization, … LC Detector Full Simulation GEANT4

11. Geometry System LCDD GDML Identifiers Sensitive Detectors Regions Physics Limits Visualization Magnetic Fields Expressions (CLHEP) Materials Solids Volumes

12. Geant4 Data Binding

13. LCDD XML Format Container Elements <lcdd> <header> <iddict> <sensitive_detectors> <regions> <limits> <display> <gdml> <define> <materials> <solids> <structure> <volume> </structure> <setup> </gdml> <fields> </lcdd> Core Elements <idspec> – identifier <sd> - sensitive detector <region> – geometry region <limitset> – set of physics limits <vis> – visualization attributes references GDML Volume Extensions <sdref> – reference to subdetector <regionref> – reference to region <limitsetref> – reference to limits <visref> – reference to vis attributes

14. Volume Element <volume name=“EcalBarrelEnvelope”> <materialref ref=“Air”/> <solidref ref=“EcalBarrelTube”/> <sdref ref=“EcalSD”/> <regionref ref=“EcalBarrelRegion”/> <limitsetref ref=“EcalBarrelLimits”/> <visref ref=“EcalBarrelLimits”/> <phsvol> <volumeref ref=“EcalLayer1”/> <physvolid id=“1”/> </physol> </volume>

15. Sensitive Detectors and Identifiers Sensitive Detectors <calorimeter name=“EMBarrel” hits_collection=“EcalBarrHits”> <idspecref ref=“EcalBarrHits”/> <projective_cylinder ntheta=“1000” nphi=“2000”/> </calorimeter> Identifiers <idspec name="EcalBarrHits" length="54"> <idfield signed="false" label="layer" length="7" start="0" /> <idfield signed="false" label="system" length="6" start="7" /> <idfield signed="false" label="barrel" length="3" start="13" /> <idfield signed="false" label="theta" length="11" start="32" /> <idfield signed="false" label="phi" length="11" start="43" /> </idspec>

16. Regions, Fields & Limits Regions Fields <region name="TrackingRegion" store_secondaries="true" cut="10.0" lunit="mm" threshold="1.0" eunit="MeV"> <limitsetref ref=“TestLimitSet”/> </regions> <solenoid name="GlobalSolenoid" inner_field="solenoid_inner_field" outer_field="solenoid_outer_field" zmin="solenoid_zmin" zmax="solenoid_zmax" inner_radius="solenoid_rmin" outer_radius="solenoid_rmax" funit="tesla" lunit="mm"/> Physics Limits <limits> <limitset name="TestLimitSet"> <limit name="step_length_max" particles="*“ value="1.0" unit="mm"/> <limit name="track_length_max" particles="pi+, pi-, p0" value="100.0" unit="cm"/> </limitset> </limits>

17. Compact Description Example Two different layer stacks in same Ecal. <detector id="2" name="EMBarrel" type="CylindricalBarrelCalorimeter" readdout="EcalBarrHits"> <dimensions inner_r = "150.1*cm" outer_z = "208.0*cm" /> <layer repeat="20"> <slice material = "Tungsten" thickness = "0.25*cm" /> <slice material = "G10" thickness = "0.068*cm" /> <slice material = "Silicon" thickness = "0.032*cm" sensitive = "yes" /> <slice material = "Air" thickness = "0.025*cm" /> </layer> <layer repeat="10"> <slice material = "Tungsten" thickness = "0.50*cm" /> <slice material = "G10" thickness = "0.068*cm" /> <slice material = "Silicon" thickness = "0.032*cm" sensitive = "yes" /> <slice material = "Air" thickness = "0.025*cm" /> </layer> </detector>

18. SLIC Overview • C++ user application using Geant4 toolkit • hub package  most of functionality implemented in subpackages • standard data formats for ILC • LCIO (output): HEP data model with generic Calorimeter and Tracker hits • StdHep (input): physics events • LCDD (input): GDML-based geometry system • command line or macro commands / interactive

19. SLIC Diagram StdHep Physics Events Simulator for the Linear Collider (SLIC) Linear Collider Detector Description (LCDD) Geometry Description Markup Language (GDML) Linear Collider IO (LCIO) reads LCIO Output File Reconstruction & Visualization SLIC Geant4 Simulator reads / writes writes reads reads LCDD XML Geometry Compact XML Geometry translated to

20. SLIC Commands • All command-line options have equivalent Geant4 command • Sample command • slic -g geometry.lcdd -i events.stdhep -x -O -l LCPhys -r 1000 • Equivalent macro • /lcdd/url geometry.lcdd • /run/initialize • /physics/select LCPhys • /generator/filename events.stdhep • /lcio/fileExists delete • /lcio/autoname • /run/beamOn 1000

21. Diagnostic Histograms • Diagnostic plots of event data • MCParticles, hits, clusters • Runs on different detectors • must have compact description • also need sampling fractions • Easy to use and setup • SLAC CVS project • cvs –d :pserver:jeremy@cvs.freehep.org:/cvs/lcd co SlicDiagnostics • ./build.sh • ./bin/SlicDiagnostics [...]

22. LCIO Overview • Object model and persistency • Events • Monte Carlo • Raw • Event and run metadata • Reconstruction • Parameters, relations, attributes, arrays, generic objects, … • All the ILC simulators write LCIO • Enables cross-checks between data from different simulators • Read/write LCIO from • Fast MC / Full Simulation • Different detectors • Different reconstruction tools

23. Physics Lists: LCPhys • standard Geant4 EM physics • hadronic models • Bertini Cascade • 0 to 9.9 GeV for p, n, pi+, pi- • 0 to 13 GeV for K+, K-, K0L, K0S, Lambda, Sigma+, Sigma-, Xi0, Xi- • Low energy parameterized models • 9.5 to 25 GeV • Quark-Gluon String Model: use for • 12 GeV to 100 TeV for p, n, pi+, pi-, K+, K-, K0L, K0S • additional neutron processes • neutron-induced fission • neutron capture • gamma-nuclear

24. Other Available Physics Lists • FTFC • Fritjof with CHIPS • FTFP • Fritjof with precompound • LHEP • low / high energy parameterised • QGSC • Quark-Gluon String with CHIPS • QGSP • Quark-Gluon String with precompound • QGSP_BERT • Quark-Gluon string with precompoind + Bertini Cascade • LHEP_BERT • low / high energy parameterised + Bertini Cascade

25. Event Sources • General Particle Source (GPS) • advanced single particle source builtin to Geant4 • angular distributions • randomized energy • one or more particles • generate in volume (box, tube, etc.) • StdHep • common binary format for event generators • HEPEVT block • your favorite event generator • PYTHIA, HERWIG, WHIZARD, etc. • LCIO • converts LCIO MCParticle block into G4PrimaryParticles • read output from other simulators (Mokka, JUPITER, etc.) • EXPERIMENTAL

26. Event Source Conversion • use LCIO MCParticle data structure for bookkeeping during simulation\\ • GPS or G4ParticleGun • no initial MCParticle collection necessary • convert directly from Geant4 trajectory container • StdHep or LCIO event source • create initial LCIO MCParticle tree • make G4PrimaryParticles for each MCParticle if • travels > mininum tracking distance • intermediate or final (documentation not tracked) • predecays • preassigned decays from the generator • assign time, daughters, etc. • Geant4 may still override (e.g. if it interacts before predecay occurs) • no vertex  determined from parent particle

27. Software Distribution • SLIC requires • Geant4, CLHEP, GDML, LCDD, Xerces, LCPhys, LCIO • Automated build system provided • Binary downloads • http://www.lcsim.org/dist/slic • Linux, Windows (Cygwin), OSX • All packages (dist) or just runtime dependencies (bin) • Or checkout and build from scratch • cvs –d :pserver:anonyous@cvs.freehep.org:/cvs/lcd co SimDist • cd SimDist; ./configure; make • Installed at SLAC, NICADD, FNAL, IN2P3, UC, ... • Report any problems to jeremym@slac.stanford.edu

28. GeomConverter LCDD slic lcio • Small Java program for converting from compact description to a variety of other formats GODL lcio lelaps GeomConverter Compact Description HEPREP wired org.lcsim Analysis & Reconstruction

29. Detector Variants • Runtime XML format allows variations in detector geometries to be easily set up and studied: • Stainless Steel vs. Tungsten HCal sampling material • RPC vs. GEM vs. Scintillator readout • Layering (radii, number, composition) • Readout segmentation (size, projective vs. nonprojective) • Tracking detector technologies & topologies • TPC, Silicon microstrip, SIT, SET • “Wedding Cake” Nested Tracker vs. Barrel + Cap • Field strength • Far forward MDI variants (0, 2, 14, 20 mr )

30. Example Geometries Cal Barrel SiD SiD Jan03 MDI-BDS Cal Endcap Test Beam

31. Far forward calorimetry Machine Detector Interface and Beam Delivery System polycones boolean solids

32. Summary • The American Linear Collider Physics Group simulation group has developed a suite of tools being used to design detectors for the ILC. • Flexible, fully-featured Geant4-based detector response simulator, slic, uses runtime detector geometry description. • Supports arbitrarily complex geometries (lcdd) • Many elements common to collider detectors are also available through a compact description • provides bindings to fastMC, visualization, reconstruction.

33. Additional Information • Wiki - http://confluence.slac.stanford.edu/display/ilc/Home • lcsim.org - http://www.lcsim.org • org.lcsim - http://www.lcsim.org/software/lcsim • Software Index - http://www.lcsim.org/software • Detectors - http://www.lcsim.org/detectors • ILC Forum - http://forum.linearcollider.org • LCIO - http://lcio.desy.de • SLIC - http://www.lcsim.org/software/slic • LCDD - http://www.lcsim.org/software/lcdd • JAS3 - http://jas.freehep.org/jas3 • AIDA - http://aida.freehep.org • WIRED - http://wired.freehep.org

34. xml: Defining a Module <module name="VtxBarrelModuleInner"> <module_envelopewidth="9.8" length="63.0 * 2" thickness="0.6"/> <module_componentwidth="7.6" length="125.0" thickness="0.26" material="CarbonFiber" sensitive="false"> <position z="-0.08"/> </module_component> <module_componentwidth="7.6" length="125.0" thickness="0.05" material="Epoxy" sensitive="false"> <position z="0.075"/> </module_component> <module_componentwidth="9.6" length="125.0" thickness="0.1" material="Silicon" sensitive="true"> <position z="0.150"/> </module_component> </module> Maryland Physics Department Colloquium

35. xml: Placing the modules <layer module="VtxBarrelModuleInner" id="1"> <barrel_envelope inner_r="13.0" outer_r="17.0" z_length="63 * 2"/> <rphi_layout phi_tilt="0.0" nphi="12" phi0="0.2618" rc="15.05" dr="-1.15"/> <z_layout dr="0.0" z0="0.0" nz="1"/> </layer> <layer module="VtxBarrelModuleOuter" id="2"> <barrel_envelope inner_r="21.0" outer_r="25.0" z_length="63 * 2"/> <rphi_layout phi_tilt="0.0" nphi="12" phi0="0.2618" rc="23.03" dr="-1.13"/> <z_layout dr="0.0" z0="0.0" nz="1"/> </layer> <layer module="VtxBarrelModuleOuter" id="3"> <barrel_envelope inner_r="34.0" outer_r="38.0" z_length="63 * 2"/> <rphi_layout phi_tilt="0.0" nphi="18" phi0="0.0" rc="35.79" dr="-0.89"/> <z_layout dr="0.0" z0="0.0" nz="1"/> </layer> <layer module="VtxBarrelModuleOuter" id="4"> <barrel_envelope inner_r="46.6" outer_r="50.6" z_length="63 * 2"/> <rphi_layout phi_tilt="0.0" nphi="24" phi0="0.1309" rc="47.5" dr="0.81"/> <z_layout dr="0.0" z0="0.0" nz="1"/> </layer> <layer module="VtxBarrelModuleOuter" id="5"> <barrel_envelope inner_r="59.0" outer_r="63.0" z_length="63 * 2"/> <rphi_layout phi_tilt="0.0" nphi="30" phi0="0.0" rc="59.9" dr="0.77"/> <z_layout dr="0.0" z0="0.0" nz="1"/> </layer> Maryland Physics Department Colloquium

36. The Barrel Vertex Detector Maryland Physics Department Colloquium

37. LCIO SimTracker Hits from Vertex CAD Drawing GEANT Volumes LCIO Hits Maryland Physics Department Colloquium