Advanced Examples

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Advanced Examples

• Alex Howard, Imperial College, UK
• on behalf of the LowE/advanced examples WG

http//www.ge.infn.it/geant4/examples/index.html
Geant4 Users Workshop, CERN, November 12th 2002
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Advanced Examples ..

• They are advanced, therefore show complete
  applications of real experiments. In some case
  simplifications but nonetheless something
  tangible from an experimental point of view
• e.g. a test-beam set-up, a module of a detector
  etc.
• Invariably can be compared with real data
• Address a wide set of inter-related issues
• the usage of simulation components in a typical
  experimental environment
• complementary interactive features (graphics,
  G/UI)
• Have up-to-date Analysis implementation
• In December AIDA 3.0 will be incorporated in ALL
  the advanced example. To switch on set the
  environment variable G4ANALYSIS_USE before
  compilation giving histogramming, plotting the
  physics results of the simulation while it is
  still running etc

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Analysis

• Its a great benefit to analyse data either after
  or during simulation
• histograms, ntuples to plot relevant physics
  distributions from the simulation
• In addition implementation within core of G4
  allows the possibility to plot histograms while
  the simulation is running, to monitor whether
  everything looks fine, or to decide when to stop
  the accumulation of statistics
• All advanced examples adopt AIDA (Abstract
  Interfaces for Data Analysis)
• to avoid introducing into Geant4 dependencies
  from any specific analysis tool
• users can choose their preferred analysis system
  (without having to change one single line of
  code) by loading the appropriate shared library
• documentation in http//www.ge.infn.it/geant4/exam
  ples/analysis.html

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X-ray telescope

• The first advanced example
• Originally a workshop project (Geant4 Workshop
  1999, hosted by ESA)
• A module of a Chandra/XMM-like telescope
• Physics for space radiation background studies

Well documented example of how to use a variety
of visualisation drivers, various (G)UI options,
GGE, GPE, histograms, ntuples etc.
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g telescope

• A tracker a calorimeter a veto counter
• Standard electromagnetic processes
• Example of how to build a simple trigger out of
  digitised signals
• How to plot histograms with physics distribution
  while the simulation is running

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X-ray fluorescence

• Test beam set-up of a typical X-ray analysis
• A photon beam impinging on a material sample the
  fluorescence spectrum of the material is measured
  by a semiconductor detector
• Physics Low Energy processes, atomic relaxation

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brachytherapy

• A general purpose application for the calculation
  of dose distributions from a radiotherapy source
• Fancy geometry to configure different
  brachyterapy techniques in the same application
• How to create/destroy/replace a geometry at
  run-time
• Low energy electromagnetic processes for precise
  calculation of dose distribution
• Developed in collaboration with cancer research
  groups in hospitals

8
Underground physics

• A liquid Xenon cell, with a typical underground
  background environment
• Record scintillation light in PMTs
• Physics neutrons, LowE processes for ions,
  scintillation, radioactive decay module etc.
• Full lab geometry (important for n scattering)
• Cavern door, cupboards, desks in the
  experimental environment
• Xenon vessel accurately reproducing a real
  prototype
• Complex primary generator (GPS) and standalone
  gun (derived)

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In preparation

• ? For Next G4 Release
• LHC-like test beam set-ups
• Atlas-like forward calorimeter
• CMS-like composite calorimeter
• LHCb-like RICH
• ? At least 2 of the 3 in the December Release.
  CMS-like composite calorimeter basis of the
  tutorial at this workshop
• ?And in the future
• Radioprotection
• Contamination from radioactive isotopes in human
  body (and environment?)
• IORT
• Model of a compact accelerator
• Gravitational wave experiment
• Space charging
• and more to come
• proposed at the G4workshop, discussed yesterday
  modular RunManager for integration in experiment
  framework

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Conclusions

• The advanced examples have been developed by
  users for users
• They offer (simplified) solution to real-life
  experimental situations and (almost) complete
  applications in a variety of disciplines from
  deep underground to deep space, including medical
  physics and (now) the LHC
• They have been produced in collaboration with
  developers and therefore demonstrate aspects of
  Geant4 not easily accessible through the manuals
  and more novice examples
• The examples offer up-to-date analysis allowing
  both interactive and batch production of user
  defined histograms
• They are an expanding area with more users
  getting involved and releasing their code with
  the general public release of Geant4
• Collaboration welcome
• More information in http//www.ge.infn.it/geant4/e
  xamples/index.html