V. Daniel Elvira

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Geant4 at Fermilab V. Daniel Elvira CD Project
Report
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Introduction
Geant4 is a toolkit for the simulation of the
passage of particles through matter. (
Collaboration of more than 100 physicists
computing professionals CERN, SLAC,,
universities )
Fermilab - fragmented, isolated but significant
contributions to
validation, support, development
- No clear plan, decreasing man-power (not
including users)


00-01 n-source BT development
support, e.m.(t), cooling simulations,
visualization, B-TeV tests, bi-annual releases
(ups/upd only the n-source version).
2 FTE 02-03 same projects as 00-01 but
more modest contributions, discontinued
n-source and added CMS in 03 (CMS
HCAL test beam implementation,
hadronic physics validation), tutorials 0.7 FTE

04 CMS HCAL physics
validation, releases, some support lt 0.5 FTE
People involved D. Elvira, L. Garren, J.
Kallenbach, P. Lebrun, P. Spentzouris,
J. Yarba
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Development, Usage, Validation
MiniBoonE
beam line (P. Spentzouris usage/support)
CDF
geometry would inherit from G4 classes to allow
use of the nice visualization tools (L. Sexton-K
overlooking usage/support)
Abandoned in 2000

test beam implementation, time performance test
documented in two BTeV notes (J. Yarba, P.
Lebrun, D. Morozov -usage/ validation/support) Sti
ll evaluating and learning. Most of the work by
INFN-Milano
BTeV
D0
Considered G4 for Run IIb in 2003 (before it was
cancelled)
Neutrino Source/Muon Collider/MICE
Visualization

Integration of the OpenInventor package to G4,
driver (J.Kallenbach development/ support)
Retired in 2001
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Development, Usage, Validation
Beam Tools
OO design of a set of classes to model
accelerator problems, n source targeted by
extensible ( D. Elvira, P. Lebrun, P.Spentzouris
) development/usage/validatio
n support)
Coolling Cell
Time dependent electric fields added to Geant4
libraries, classes to construct magnets, r.f.
cavities, absorbers, r.f. tuning mechanism,
interface to Root cooling simulations,
bunching, phase rotation
Publications n source feasibility study, gt5
conference proceedings, user manual (Fermi-pubs),
many experiment internal notes, article to JCP
(in preparation) Web Page cepa.fnal.gov/psm/g
eant4/G4BeamTools
Stopped by end of 2002, minimal support in 2003
(MICE has performed further development
mantainance)
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Development, Usage, Validation
CMS
Hcal test beam

• OSCAR librarian (H. Wenzel -support)
  Retired in 2003

eCal
HO
Beam Line

• Hcal02 test beam simulation OSCAR validation
  (V. Daniel Elvira -usage/validation)
  Current

HB
HO
100 GeV pion

• US-CMS users based at Fermilab (S. Esen, Taylan
  Yetkin) Current

TB02-03 programs tested pions 20-300 GeV range.
TB04 will test low energies 2-9 GeV, transverse
and longitudinal profiles
Critical for hadronic physics validation (big
impact in understanding jetMET) critical for
Higgs/New phenomena discovery
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Development, Usage, Validation
Significant progress in understanding hadronic
physics. Joint effort of the CERN LCG-validation
group (LCG note in preparation.) More to come in
2004 !
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Development, Usage, Validation
CMS note draft ready and another one in
preparation
Transverse Profile
Longitudinal Profile
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Support

• Successful 3-days Geant4 tutorial Fermilab-SLAC
  tutorial held at Fermilab (October 2003)
  conferences.fnal.gov/g4tutorial

• More than 50 people attended (CMS, D0, CDF,
  neutrinos, etc).
• 8 to 12 people at a time followed
  video-stream transmission live.
• All tutorial videos available in the Visual
  Media Services web page (thanks to CMS-CD
  department)

Good training for current and to be LHC
collaborators !
Close contact with Geant4 principals (joint
tutorials with SLAC experts M. Asai -
co-spokesperson et al., periodic
conversations with J. Apostolakis at CERN
co-spokesperson)
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Support

• Geant4 web page at Fermilab cepa.fnal.gov/psm/g
  eant4

Picture CMS HCAL test beam 02
simulation
G4-CERN home page
Workshops
Tutorial at Fermilab
CMS simulations
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Support

• We have a listserv.fnal.gov gean4-users (little
  activity)

• We try to have latest Geant4 version available
  to users (ups/upd)
• geant_4_6_0 (4_6_1 is supposed to have physics
  related bugs)
• There are 2 major annual releases (June,
  December) x 1-2 patches x 1-2 intermediate
  versions lt 8 annual releases.
• Past wait for patches to come (a few weeks
  from main release), and built geant4 for the
  Linux, gcc, visualization combination used for
  n-source applications.
• Number of users increasing exponentially
• - CMS is a big Geant4 consumer
  
  - for example BTeV has recently requested 5
  different combinations of operating
  system compiler
• - Requests from individuals (standalone
  use) surged recently Andreas
  Jansson (Tevatron), Sudhir Malik (D0), Alan Bross
  (explosive detectors), Hogan Nguyen,
  CMS-HCAL visitors/students, etc.

We are doing badly answering these requests
state of crisis
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Future (as I thought it in March 2003)
Geant4 is a young adult time to setup a
local collaborative group (Fermilabusers) with
critical mass for
Still a good idea, and now we have the LPC

• Providing expertise
• Support ?
• Development ?

Initially centered around CMS expanding as the
Fermilab program becomes more clear i.e. request
from LCG for participation in a G4 fast shower
parameterization project
We actually collaborated with the LCG group on
validation
Not critical, but natural
Join the Geant4 Collaboration (rules more
flexible now) ? Organize users
meeting/tutorials by 2004 ?
We did it
Isolated/fragmented effort project, need
at least 1 more FTE to achieve the most modest
goals
Still true
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Basic Proposal for Support Activities
Based on 1 additional FTE (CP with physics
background)

• Make Geant4 code available at Fermilab

For standalone users Build the G4 libraries in a
FNALU Linux node (i.e. flxi02) consistent with
operating system, compiler, visualization tools
made available there. It would be a ups/upd
product.
For experiments Potentially time consuming, not
clear it would be practical either. - Number of
releases In the case of BTeV, would we need up
to 5x840 releases per year? - Customization
Experiments tend to make their own unique
choices. CMS would not be interested.

• Be informed about the changes bug fixes,
  improvements
• Maintain web page, keep the listserv
  GEANT4-users active
• Know the basics on G4 took kit usage to help
  setup applications and answer questions on
  gun, geometry, e.m. field, physics,
  visualization, interface with analysis code.

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Extended Proposal for Support Activities

• Physics expert (understand, incorporate/modify,
  write code related with physics models)
• Need of the Geant4 Collaboration from a
  conversation with J. Apostolakis).
• Local magnetic field management to increase
  speed (by using different steppers, accuracy
  parameters in different regions)
• A need of the CMS Collaboration

• Parallelization of Geant4 (may need external
  funding)
• Some tests were done in the past at
  Northeastern University
• Need of the Geant4 Collaboration from a
  conversation with J. Apostolakis).

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CMS G4/OSCAR Potential Activities

• CMS OSCAR/G4 projects Framework, geometry,
  physics, propagation

- Take over HCAL representation after the
summer - Write DDD-XML versions of geometry for
some sub-detectors. - Develop tools to quickly
validate new OSCAR releases - Framework tool to
mix FAMOS (fast simulation) and OSCAR. In
general overlap tools like MC with data, TB
single particle with MC pileup. - Migration to
HEPMC (common interface with all generators). -
Physics/validation Test beam 04 data analysis,
comparison with simulations, modifications to
physics models.
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Future (as I think of it today)

• There has been significant progress in the
  understanding of the G4 hadronic physics, and
  there is more to come (LHC test beam programs)

• Geant4 has been adopted by major collaborations
  CMS, ATLAS, and BTeV (?). CMS is generating
  millions of G4 events which will be analyzed
  and be part of the physics TDR due by the end of
  2005

CMS is a significant part of the Fermilab
program the LHC Physics Center (LPC) should
develop expertise on simulation, reconstructions,
particle ID, physics.
Significant increase in the number of users who
need support (both for experiment related or
standalone applications)
The project needs at least 1 additional FTE to
maintain the basic G4 support and activities, gt 2
additional FTEs for extended program.