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0002
0003 =========================================================
0004 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
0005 =========================================================
0006
0007 amsEcal
0008 -------
0009
0010 1- GEOMETRY DEFINITION
0011
0012 AMS Ecal calorimeter is described in the joined documument : ams_ecal.pdf
0013
0014 - A single layer is a plane of scintillating fibers within a box of
0015 absorber material.
0016 - Single layers are positionned (eg. placement) within Module
0017 (called SuperLayer in the descriptive document),
0018 alternatively with a relative offset of +- 0.25*distanceInterFibers.
0019 - Modules are positionned within calorimeter, alternatively rotated of
0020 90 deg around beam axis (X_axis).
0021 Therefore all fibers are along Y_axis or Z_axis calorimeter.
0022
0023 The default geometry is constructed in DetectorConstruction class.
0024 In addition a transverse uniform magnetic field can be applied.
0025
0026 2- PHYSICS LISTS
0027
0028 Physics lists can be local (eg. in this example) or from G4 kernel
0029 (physics_lists subdirectory).
0030
0031 - "local" standard EM physics with current 'default' options.
0032
0033 From geant4/source/physics_lists/constructors:
0034 - "emstandard_opt0" standard EM physics with all default options
0035 - "emstandard_opt1" best CPU performance standard physics for LHC
0036 - "emstandard_opt2"
0037 - "emstandard_opt3"
0038
0039 Physics lists and options can be (re)set with UI commands
0040
0041 Please, notice that options set through G4EmProcessOPtions are global, eg
0042 for all particle types. In G4 constructors, it is shown how to set options per
0043 particle type.
0044
0045 3- PRIMARY GENERATOR : mono-energetic pencil beam
0046
0047 The primary kinematic is a single particle which hits the calorimeter
0048 perpendicular to the input face (eg. along X_axis).
0049 The type of particle and its energy are set in the PrimaryGeneratorAction,
0050 and can be changed via the G4 build-in commands of ParticleGun class
0051 (see the macros provided with this example).
0052
0053 One can choose randomly the tranverse position of the incident particle,
0054 eg. the width of the beam. The associated interactive command is built
0055 in PrimaryGeneratorMessenger.
0056
0057 4- DETECTOR RESPONSE
0058
0059 The program computes the 'visible' energy, eg. the energy deposited
0060 in scintillating fibers.
0061
0062 It also computes the total energy deposited per layer, either in absorber
0063 material or in scintillator material.
0064
0065 The list of fibers fired can be written event per event, on an ascii file.
0066 The file is filled at EndOfEvent(); uncomment the function WriteFibers()
0067 See EventAction::WriteFibers() and the format description : eventFormat.txt
0068
0069 NB: visible energy can be corrected for Birk's attenuation:
0070 see the function SteppingAction::BirksAttenuation() (not activated)
0071
0072 5- HISTOGRAMS
0073
0074 The Program contains 5 built-in 1D histograms, managed by G4AnalysisManager.
0075 These histograms can be activated individually with the command :
0076 /analysis/h1/set id nbBins valMin valMax unit
0077 where unit is the desired unit for the histo (MeV, keV, etc..)
0078 (see the macros xxxx.mac).
0079
0080 1 total energy in calorimeter (eg. summed all layers)
0081 2 vsible energy in calorimeter (eg. summed all layers)
0082 3 total energy per layer (eg. longitudinal profile)
0083 4 visible energy per layer (eg. longitudinal profile)
0084 5 visible energy per fiber (eg. lateral profile)
0085
0086 Histograms can be viewed using ROOT.
0087
0088 One can control the name and format of the histograms file with the command:
0089 /analysis/setFileName name (default amsEcal)
0090 /analysis/setFileType type (choice: root(default), XML, csv)
0091
0092 It is also possible to print selected histograms on an ascii file:
0093 /analysis/h1/setAscii id
0094 All selected histos will be written on a file name.ascii (default amsEcal)
0095
0096 6- VISUALIZATION
0097
0098 Visualization Manager is set in the main().
0099 Initialisation of the drawing is done via the commands :
0100 /vis/... in the macro vis.mac. In interactive session:
0101 PreInit or Idle > /control/execute vis.mac
0102
0103 Default view is a longitudinal view of the calorimeter.
0104
0105 Tracks are drawn at end of event, and erased at end of run.
0106 Optionaly one can choose to draw all particles, only charged one, or none.
0107 This command is defined in EventActionMessenger.
0108
0109 7- HOW TO START ?
0110
0111 - compile and link to generate an executable
0112 % cd amsEcal
0113 % gmake
0114
0115 - execute amsEcal in 'batch' mode from macro files
0116 % amsEcal run1.mac
0117
0118 - execute amsEcal in 'interactive mode' with visualization
0119 % amsEcal
0120 ....
0121 Idle> type your commands. For instance:
0122 Idle> /control/execute run1.mac
0123 ....
0124 Idle> exit
0125
0126 8- HANDLE RANDOM NUMBER SEEDS
0127
0128 The macro rndmSeed.mac shows how to create a set of random number seeds.
0129 Here we save the seed at begin of each run (the number of events per run
0130 is arbitrary). The seeds are stored in subdirectory random.
0131
0132 Macro rndmSeed.mac shows also how to start a run from one of these seeds.
