1. Advanced Examples Alex Howard, Imperial College, UK
on behalf of the LowE/advanced examples WG
Geant4 Users Workshop, CERN, November 12th 2002

2. 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…

3. Analysis
It’s 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

4. 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.

5. 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

6. 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
Scattered
photons
Fe lines
GaAs lines
sample
detector
beam

7. 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 mirror LXe GXe source PMT
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)
LXe
GXe
PMT
mirror
source

9. In preparation And in the future:  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

10. More information in http://www.ge.infn.it/geant4/examples/index.html
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