# Presentation: 175976

## Detector Simulation (Geant4) Activities at Fermilab

- V. Daniel Elvira
- CD Project Report

## Outline

-  PSM Current Activities on Detector Simulations:
-       LHC Physics Center (LPC).
-       CMS Experiment.
-       Fermilab Users Support (J. Yarba’s talk next).
-  Fermilab Proposal to the Geant4 Collaboration:
-       Tool kit development projects by PSM core group.
-       Collaboration with other Fermilab interested parties.

**Outline**

## What is Geant4 ?

- Fermilab is not yet a collaborating institution, a situation that partially limits the fulfillment of our mission.

**What is Geant4 ?**

**PSM and Detector Simulations**

- _Mission:_ support, stimulate, initiate simulation efforts associated with Fermilab programs; develop detector simulation expertise, including the use of software tools (nowadays mainly Geant4), among Fermilab users.

## Recent History at the Lab

- People involved: D. Elvira, L. Garren, J. Kallenbach, P. Lebrun,
-                          P. Spentzouris, J. Yarba

-   Implementation of time dependent EM fields in Geant4, visualization
-  Beam Tools to simulate accelerator elements – cooling simulations for Neutrino Source and Muon Collider feasibility studies.
-  CMS Hcal Test Beam simulation and hadronic physics validation
-  MiniBoone beam line, BTeV simulation framework, applications, and tests
-  Local installation of Geant4 releases twice a year
-  Three days tutorials in 2003, general support to FNAL users

**Recent History at the Lab**

## Current PSM Group Activities

- Daniel Elvira (scientist) –  85% simulation activities (down to 50% in 07)
- Julia Yarba (CP) – 100% simul. activities
- Sunanda Banerjee coming Sept06 (App. Phys.) – 100% simul. activities

- _In 05-06:_   improve general simulation support (see Julia’s talk),  support/participation USCMS simulation activities at the LPC, ILC-SLIC releases (L. Garren).
- _From 06 on:_  expand general simulation support, continue LPC/CMS activities, participate of G4 development as collaborating institution

-  Decision made to build a Geant4 core group within PSM

**Current PSM Group Activities**

## The LPC Simulations Group

- _LHC Physics Center_ created to provide USCMS collaborators with a physical place to work in their own time zone where they will find: a remote control room, excellent video meeting resources,  computing infrastructure, software expertise, and all elements to do physics in a collaborative environment.
-  LPC = the US CMSD0 equivalent of the D0 or CDF trailers.
-            A “virtual building 40” this side of the Atlantic
- _Simulations Group_:  H. Cheung, D. Elvira (Leaders), Julia Yarba (support, infrastructure software development, code integration)
- Provide support, generate expertise to help USCMS institutions to carry out their own simulation projects

- _Participating Institutions in LPC-Simulations:_  Brown, Carnegie-Melon, Colorado, FNAL, FSU, KSU, KU, Maryland, Mississippi, Northwestern, Notre Dame, Purdue-Calumet, Rutgers, Rockefeller, SUNY-Buffalo, UIC (USA)
-                                ~ 20 people, 70 in mailing list

## LPC-Simulation Activities

-  Luminosity Monitoring System Simulation
-  ECAL Crystal Response Studies
-  Zero Degree Calorimeter (ZDC) in Simulation
-  Forward Pixels Geometry and Simulation
-  Geant4 physics validation using TB data
-  Simulation Validation Suite
-   GFlash parameterization of hadronic showers

- Large and growing fraction of CMS simulation activities

- _Julia Yarba is a key contributor_ to infrastructure development (particle gun, vertex smearing), integration (simulation chain, validation suite), testing (debugging & timing studies), and support (questions, tutorials)
- _Responsibilities in international CMS:_  simulation group co-coordination & Physics Software Validation group coordination (D. Elvira).

- If you are a member of international CMS and work on simulations, the LPC is the best place to be

## The Phys. Soft. Validation Suite

-     PSVS software sub-systems
-     (dedicated  packages)

- Pre-generated samples:
- single particles,
- pp physics
- (Pool files,
- ROOT browsable, HepMC format)

**Packages currently available: Performance, Mixing,TrackerHits, TrackerDigis, EcalHits, EcalDigis, HcalHits, HcalDigis, Geometry, GlobalHits, TrackerRecHits, DTMuonsRecHits**

- Validation branch
- (Pool files,
- ROOT browsable)

- OVAL

- Configuration file: commands, tolerance values

**The Phys. Soft. Validation Suite**

- Detect automatically and correct problems in new release with respect to a previous reference.
-  The LPC developed the Simulation Validation Suite (G4 hits) – late 2005
-  Charge to the PSV Group: Develop Physics Software Validation Suite, for hits, digis, rechits, physics objects for CMSSW.

## PSVS: People & Documentation

- _USCMS Institutions and People Involved with PSVS:_
- S. Abdullin, H. Cheung, D. Elvira, J. Yarba – FNAL
- X. Huang -  Mayaguez (Puerto Rico),
- A. Kharchilava, M. Strang -SUNY Buffalo,
- L. Shabalina - UIC
- D. Andulin – Virginia
- + many more from international CMS

- _Status:_  first integrated version of the PSVS to be commissioned with CMSSW_07_0 by mid-June 2006

## HCAL TB04 Data/MC Comparison

**HCAL TB04 Data/MC Comparison**

- Final data analysis results from HCAL TB 2004 from _J. Damgov_,
- compared with Geant4 predictions by _S. Piperov_, based on
- OSCAR/G4.6.2.p02. Part of PTDR and shown in LCG-Simulation Validation

- VLE beam (ATLAS result not available yet)

- Plan to compare this data with G4.7.1 and G4.8.0 (improved hadronic shower)

## HCAL TB04 Data/MC Comparison

**HCAL TB04 Data/MC Comparison**

- TB06 this
- summer: better
- particle ID for
- VLE beams.

## Forward Pixels Simulation

- People Involved:
- Victoria Martin (NW) – wrote plaquette geometry
- Dmitri Onoprienko (KS) – main geometry developer (DDD expert)
- Xingtao Huang (Mayaguez/Pto.Rico) – implemented numbering scheme, simulation under CMSSW, digi validation.
- Colorado group - geometry of pixel service cylinder, partial pixel test 07
- Neeti Parashar (LTU-Calumet) – geometry, hits, validation representative to simulation and validation groups.

- Activity initiated at the LPC in March 2005. Now these team is a main player in the pixels simulation

- _Status:_ simulation operational under CMSSW,  geometry re-written to reflect changes in engineering drawings. Validation packages ready for integration to the suite.

## Forward Pixels Simulation (II)

- Disks

- Pannel

- Plaquette

## Zero Degree Calorimeter (ZDC)

**Zero Degree Calorimeter (ZDC)**

- _People Involved:_  Michael Murray-Project Manager (KU)
-                            Megan Lehnherr (KU),  Chadd Smith (UIC)– in OSCAR
-                            Edmundo Garcia (UIC) ported to CMSSW

- _Status:_   Edmundo Garcia recently finished the porting the standalone
-               ZDCTest simulation to CMSSW, fixed bugs, validate physics of G4
-               using RIHC test beam experiment. Next: digitization, shower parameteriz.

- # of photons per fiber in layers of Hadronic section of ZDC
- 1000 GeV neutron
- 500 GeV neutron

## GFlash Parameteriz. of Hadronic Showers

- GFlash is a package (developed by H1) to parameterize particle
- showers in a MC simulation. We could gain:
-  Speed, but this is not main goal.
-  _Accuracy_, by tuning it to data in case that the MC is not accurate enough.
- The Geant4 team is working hard to understand underlying physics processes in the particle shower, and provide a most accurate product possible given the current physics knowledge.
- GFlash can help us take the additional step towards final tuning of our detector simulation to test beam and collider data.
- Long Term Goal: accurate (and fast enough) MC to derive, understand, estimate corrections, systematic uncertainties in data analysis.

- _USCMS (LPC) Team_: R. Godang & R. Kroeger (Mississippi), Soon Jun & M. Paulini (Carnegie-Mellon), Anwar Bhatti (Rockefeller) + others from international CMS

## The Future

- With very little man-power our proto-Geant4 core group initiated,
- enabled, and currently supports a significant amount of simulation activity
- Related to Fermilab research programs.
- Where/how should be expand?
- Should we become members of the Geant4 Collaboration?
- Number 1 is an open question: ILC, neutrino, astrophysics experiments,...
- YES to 2. The high level of expertise needed to pursue  our goals can only
- be achieved through direct participation in the simulation toolkit
- development team. Collaboration membership would also enable Fermilab to
- have a say in the future evolution of the project, as well as improve
- communication in both directions.

- Fermilab Proposal to the Geant4 Collaboration in preparation

## The Proposal

- _Who?_
- The members of the PSM Geant4 core group (Julia, Sunanda, Daniel) & all
- who are willing to do work would be members of the G4 Collab.
- Other interested parties will be invited to sign the proposal in support.
- _Conditions:_ presentation of proposal (no # FTE requirement). But 2 FTE
- needed for representation in the Steering Board (direction of the
- Collaboration)
- _What?_
- Hadronic Physics. An area of significant interest for Fermilab programs
- and scientists: hadron calorimetry at the ILC and LHC, neutrino fluxes and
- atmospheric showers. An area where the G4 team is in need for help.
- _For How Long?_
- For as long as Geant4 is relevant to the Fermilab programs or
- all related issues of interest have been addressed/solved.

## Hadronic Physics

- Physics modeling of hadronic interations for ranges from
- thermal energies for neutron cross-sections, through ~7 TeV
- (LHC), to higher energies in cosmic ray physics.
- _Interaction Cross-Sections and Modeling of final states:_
- measured data, parameterizations/extrapolations based on
- experimental data under theoretical assumptions, or theory
- based.
- _Examples (physics “sets” or “lists”):__ _
- LHEP model based on data carried over from Geant4
- (GHEISHA)
- QGSP based on Quark Gluon String theoretical model for high
- Energy hadron-nucleus inelastic scattering.

## Hadronic Physics Tasks

-  _Validation._ Connect macroscopic quantities (such as shower shapes) with Geant4 physics processes and identify the problems.

**Hadronic Physics Tasks**

-  _Others:_  Alternate models.
-                 Had. shower parameterization infrastructure,...

- Current issue is that showers too narrow and short at high E. Investigating, by particle type, contributions from process cross-section, neutron production, energy spectrum at different depths, etc. Current LHC TB programs useful tool for validation.

- Iterating with G4 Collaboration

## Summary

- Follow model of creating user based teams for relevant projects.
- Ready to take next step: Geant4 toolkit development
- Opportunities to collaborate with Fermilab user institutions, eventually external funding.

**Summary**