field/field02/README.md

0001 \page Examplefield02 Example  field02
0002
0003  Test for investigation of tracking in electric field
0004  and field dependent electromagnetic processes.
0005
0006 ## FIELD DEFINITION
0007  The field is a constant electric field.
0008
0009  Technical note: in order to use any electric field, it is
0010  necessary to create the objects for its equation of motion,
0011  the stepper and driver for the integration, and the
0012  chord finder.
0013
0014  The class that does these is G4FieldBuilder. Its object
0015  is created in the F02DetectorConstruction constructor and
0016  its instantiation adds the /field UI commands that allow user
0017  to choose the field configuration parameters.
0018
0019  The electric field (G4UniformElectricField) is then created in
0020  F02DetectorConstruction::ConstructSDandField() and passed to
0021  G4FieldBuilder, that constructs all necessary objects according
0022  to the user defined (or default) configuration parameters.
0023
0024 ## GEOMETRY DEFINITION
0025
0026  The "Absorber" is a solid made of a given material.
0027
0028  Three parameters define the absorber :
0029  - the material of the absorber,
0030  - the thickness of an absorber,
0031  - the transverse size of the absorber (the input face is a square).
0032
0033  The volume "World" contains the "Absorber".
0034  In this test the parameters of the "World" can be changed , too.
0035
0036  In addition a transverse uniform electric field can be applied.
0037
0038  The default geometry is constructed in F02DetectorConstruction class,
0039  but all the parameters can be changed via
0040  the commands defined in the F02DetectorMessenger class.
0041
0042 ## AN EVENT : THE PRIMARY GENERATOR
0043
0044  The primary kinematic consists of a single particle which hits the
0045  absorber perpendicular to the input face. The type of the particle
0046  and its energy are set in the F02PrimaryGeneratorAction class, and can
0047  be changed via the G4 build-in commands of G4ParticleGun class (see
0048  the macros provided with this example).
0049
0050  It is also possible to change the position of the primary particle vertex
0051  or activate its randomization via the commands defined in  the
0052  F01PrimaryGeneratorMessenger class.
0053
0054  A RUN is a set of events.
0055
0056 ## DETECTOR RESPONSE
0057
0058
0059  A HIT is a record, event per event , of all the
0060  informations needed to simulate and analyse the detector response.
0061
0062  In this example a F02CalorHit is defined as a set of 2 informations:
0063  - the total energy deposit in the absorber,
0064  - the total tracklength of all charged particles in the absorber,
0065
0066  Therefore  the absorber is declared
0067  'sensitive detector' (SD), see F02CalorimeterSD, which means they can contribute to the hit.
0068
0069 ## PHYSICS LIST
0070
0071  The particle's type and the physic processes which will be available
0072  in this example are set in the FTFP_BERT physics list. This physics list
0073  requires data files for electromagnetic and hadronic processes.
0074  See more on installation of the datasets in Geant4 Installation Guide,
0075
0076 ## HOW TO START ?
0077
0078  - Execute field02 in 'batch' mode from macro file e.g.
0079 ```
0080 % ./field02 field02.in
0081 ```
0082
0083  - Execute field02 in 'interactive' mode with visualization e.g.
0084 ```
0085 % ./field02
0086 ....
0087 Idle> /run/beamOn 1
0088 ....
0089 ```