Gabriele Cosmo
152 lines
5.2 KiB
Plaintext
152 lines
5.2 KiB
Plaintext
$Id: README,v 1.26 2008/10/23 13:08:23 maire Exp $
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-------------------------------------------------------------------
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=========================================================
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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=========================================================
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TestEm2
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-------
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How to do shower profiles in an homogenous medium, with virtual
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voxelisation.
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1- GEOMETRY DEFINITION
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The geometry consists of a cylinder of homegenous material.
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The default geometry is constructed in DetectorConstruction class,
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but all of the above parameters can be modified interactively via
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the commands defined in the DetectorMessenger class.
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Material can be choosen: Air Water lAr Al Fe BGO PbWO4 Pb.
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eg: /testem/det/setMat PbWO4
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The cylinder is virtually sliced longitudinaly (slice) and radialy (ring).
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The size of the slices and rings are expressed in radiation length units
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and can be changed.
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eg: /testem/det/setLbin 20 1. ---> 20 slices of 1. radl
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/testem/det/setRbin 5 0.25 ---> 5 rings of 0.25 radl
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/testem/det/update ---> rebuild the geometry
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(MaxBin = 500 in both directions)
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An uniform magnetic field along the cylinder axis can be set.
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eg: /testem/det/setField 5 tesla
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2- PHYSICS LISTS
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Physics lists can be local (eg. in this example) or from G4 kernel
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physics_lists subdirectory.
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Local physics lists:
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- "standard" standard EM physics with current 'best' options setting.
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these options are explicited in PhysListEmStandard
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- "livermore" low-energy EM physics using Livermore data
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- "penelope" low-energy EM physics implementing Penelope models
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From geant4/source/physics_lists/builders:
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- "emstandard" recommended standard EM physics for LHC
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- "emstandard_opt1" best CPU performance standard physics for LHC
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- "emstandard_opt2"
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- "emstandard_opt3"
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Physics lists and options can be (re)set with UI commands
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Please, notice that options set through G4EmProcessOPtions are global, eg
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for all particle types. In G4 builders, it is shown how to set options per
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particle type.
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3- AN EVENT : THE PRIMARY GENERATOR
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The primary kinematic consists of a single particle which hits the
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cylinder perpendicular to the input face. The type of the particle
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and its energy are set in the PrimaryGeneratorAction class, and can
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changed via the G4 build-in commands of ParticleGun class (see
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the macros provided with this example).
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A RUN is a set of events.
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4- VISUALIZATION
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The Visualization Manager is set in the main().
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The initialisation of the drawing is done via the commands
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/vis/.. in the macro vis.mac. In interactive session:
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PreInit or Idle > /control/execute vis.mac
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The detector has a default view which is a longitudinal view of the
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cylinder.
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The tracks are drawn at the end of event, and erased at the end of run.
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Optionaly one can choose to draw all particles, only the charged one,
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or none. This command is defined in EventActionMessenger class.
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5- PHYSICS DEMO
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The particle's type and the physic processes which will be available
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in this example are set in PhysicsList class.
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In addition a build-in interactive command (/process/inactivate proname)
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allows to activate/inactivate the processes one by one.
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The threshold for producing secondaries can be changed.
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eg: /testem/phys/setCuts 100 microm
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/run/initialize
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The shower profiles are histogramed, if histograming is activated.
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They can be also printed with the command /testem/run/verbose 1
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6- HOW TO START ?
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- compile and link to generate an executable
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% cd TestEm2
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% gmake
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- execute TestEm2 in 'batch' mode from macro files
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% TestEm2 run01.mac
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- execute TestEm2 in 'interactive mode' with visualization
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% TestEm2
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....
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Idle> type your commands
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....
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Idle> exit
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7- HISTOGRAMS
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TestEm2 produces several histograms:
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Content of these histo:
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1 : energy deposit per event
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2 : charged track length per event
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3 : neutral track length per event
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4 : longitudinal energy profile
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5 : cumulated longitudinal energy profile
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6 : rms of cumulated longitudinal energy profile
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7 : radial energy profile
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8 : cumulated radial energy profile
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9 : rms of cumulated radial energy profile
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Note that, by default, histograms are disabled. To activate them, uncomment
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the flag G4ANALYSIS_USE in GNUmakefile. To define the output file name with
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histograms and the type of these file the following UI commands can be used:
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"/testem/histo/setFileName name"
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"/testem/histo/setFileType type"
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The following types are available: "hbook", "root", "XML"
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By default the name is "testem2" and the type "root".
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Before compilation of the example it is optimal to clean up old files:
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gmake histclean
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gmake
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8- USING HISTOGRAMS
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To use histograms, at least one of the AIDA implementations should be
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available. See InstallAida.txt
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