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0003 =========================================================
0004 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
0005 =========================================================
0006
0007 field03
0008 -------
0009
0010 Example of tracking in magnetic field where field associated
0011 to selected logical volumes varies.
0012
0013 A global and a local magnetic field are defined in
0014 the ConstructSDandField() method in the F03DetectorConstruction class
0015 using the G4FieldBuilder class.
0016 The local magnetic field is set to the "Radiator" volume.
0017
0018 The interactive commands, under the /field directory, are created with
0019 the instantiation of G4FieldBuilder in the F03DetectorConstruction constructor,
0020
0021 1- GEOMETRY DEFINITION
0022
0023 The "Absorber" is a solid made of a given material.
0024
0025 Three parameters define the absorber :
0026 - the material of the absorber,
0027 - the thickness of an absorber,
0028 - the transverse size of the absorber (the input face is a square).
0029
0030 The volume "World" contains the "Absorber".
0031 In this test the parameters of the "World" can be changed , too.
0032
0033 A transverse global uniform magnetic field can be applied.
0034 In addition, the "Radiator" volume, which is placed in geometry next
0035 to the absorber, has a local magnetic field.
0036
0037 The default geometry is constructed in F03DetectorConstruction class,
0038 but all the parameters can be changed via
0039 the commands defined in the F03DetectorMessenger class.
0040
0041 2- AN EVENT : THE PRIMARY GENERATOR
0042
0043 The primary kinematic consists of a single particle which hits the
0044 absorber perpendicular to the input face. The type of the particle
0045 and its energy are set in the F03PrimaryGeneratorAction class, and can
0046 be changed via the G4 build-in commands of G4ParticleGun class (see
0047 the macros provided with this example).
0048
0049 It is also possible to change the position of the primary particle vertex
0050 or activate its randomization via the commands defined in the
0051 F01PrimaryGeneratorMessenger class.
0052
0053 A RUN is a set of events.
0054
0055 3- DETECTOR RESPONSE
0056
0057 A HIT is a record, event per event , of all the
0058 informations needed to simulate and analyse the detector response.
0059
0060 In this example a F03CalorHit is defined as a set of 2 informations:
0061 - the total energy deposit in the absorber,
0062 - the total tracklength of all charged particles in the absorber,
0063
0064 Therefore the absorber is declared
0065 'sensitive detector' (SD), see F03CalorimeterSD, which means they can contribute to the hit.
0066
0067 4- PHYSICS LIST
0068
0069 The particle's type and the physic processes which will be available
0070 in this example are set in the FTFP_BERT physics list. This physics list
0071 requires data files for electromagnetic and hadronic processes.
0072 See more on installation of the datasets in Geant4 Installation Guide,
0073
0074 5- HOW TO START ?
0075
0076 - Execute field03 in 'batch' mode from macro files e.g.
0077 % ./field03 field03.in
0078
0079 - Execute field03 in 'interactive' mode with visualization e.g.
0080 % ./field03
0081 ....
0082 Idle> /run/beamOn 1
0083 ....
