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0003 =========================================================
0004 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
0005 =========================================================
0006
0007 field02
0008 -------
0009
0010 Test for investigation of tracking in electric field
0011 and field dependent electromagnetic processes.
0012
0013 1- FIELD DEFINITION
0014 The field is a constant electric field.
0015
0016 Technical note: in order to use any electric field, it is
0017 necessary to create the objects for its equation of motion,
0018 the stepper and driver for the integration, and the
0019 chord finder.
0020
0021 The class that does these is G4FieldBuilder. Its object
0022 is created in the F02DetectorConstruction constructor and
0023 its instantiation adds the /field UI commands that allow user
0024 to choose the field configuration parameters.
0025
0026 The electric field (G4UniformElectricField) is then created in
0027 F02DetectorConstruction::ConstructSDanField() and passed to
0028 G4FieldBuilder, that constructs all necessary objects according
0029 to the user defined (or default) configuration parameters.
0030
0031 1- GEOMETRY DEFINITION
0032
0033 The "Absorber" is a solid made of a given material.
0034
0035 Three parameters define the absorber :
0036 - the material of the absorber,
0037 - the thickness of an absorber,
0038 - the transverse size of the absorber (the input face is a square).
0039
0040 The volume "World" contains the "Absorber".
0041 In this test the parameters of the "World" can be changed , too.
0042
0043 In addition a transverse uniform electric field can be applied.
0044
0045 The default geometry is constructed in F02DetectorConstruction class,
0046 but all the parameters can be changed via
0047 the commands defined in the F02DetectorMessenger class.
0048
0049 2- AN EVENT : THE PRIMARY GENERATOR
0050
0051 The primary kinematic consists of a single particle which hits the
0052 absorber perpendicular to the input face. The type of the particle
0053 and its energy are set in the F02PrimaryGeneratorAction class, and can
0054 be changed via the G4 build-in commands of G4ParticleGun class (see
0055 the macros provided with this example).
0056
0057 It is also possible to change the position of the primary particle vertex
0058 or activate its randomization via the commands defined in the
0059 F01PrimaryGeneratorMessenger class.
0060
0061 A RUN is a set of events.
0062
0063 3- DETECTOR RESPONSE
0064
0065
0066 A HIT is a record, event per event , of all the
0067 informations needed to simulate and analyse the detector response.
0068
0069 In this example a F02CalorHit is defined as a set of 2 informations:
0070 - the total energy deposit in the absorber,
0071 - the total tracklength of all charged particles in the absorber,
0072
0073 Therefore the absorber is declared
0074 'sensitive detector' (SD), see F02CalorimeterSD, which means they can contribute to the hit.
0075
0076 4- PHYSICS LIST
0077
0078 The particle's type and the physic processes which will be available
0079 in this example are set in the FTFP_BERT physics list. This physics list
0080 requires data files for electromagnetic and hadronic processes.
0081 See more on installation of the datasets in Geant4 Installation Guide,
0082
0083 5- HOW TO START ?
0084
0085 - Execute field02 in 'batch' mode from macro file e.g.
0086 % ./field02 field02.in
0087
0088 - Execute field02 in 'interactive' mode with visualization e.g.
0089 % ./field02
0090 ....
0091 Idle> /run/beamOn 1
0092 ....
