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

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…

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 http://www.ge.infn.it/geant4/examples/analysis.html

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.

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

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

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

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

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

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 http://www.ge.infn.it/geant4/examples/index.html