GEOMETRY DEFINITION

The geometry consists of a single block of a homogenous material, placed in a world.

Four parameters define the geometry :

the material of the box
the thickness of the box
the tranverse dimension of the box
the maximal step size in target

The default is 10 cm of alumunium, step is limited by 5mm. Equivalent UI commands are following:

/testex/det/setMat G4_Al
/testex/det/sizeX  10 cm
/testex/det/sizeYZ 5 cm
/testex/det/setStepSize 5 mm

The default geometry is constructed in DetectorConstruction class, but all of the above parameters can be changed interactively via the commands defined in the DetectorMessenger class.

In addition, a global, uniform, and transverse magnetic field can be applied via G4MonopoleFieldSetup class, with the default z-value 0.2 tesla. This value can be changed via UI command:

/testex/fld/setField 0.2 tesla

PHYSICS LIST

The physics list includes standard FTFP_BERT physics and the additional builder for monopole physics. To define monopole parameters an extra string should be provided via the program arguments:

./monopole -s '2 0 200 GeV'              # in the interactive mode
./monopole -m file.mac -s '2 0 200 GeV'  # in the batch mode

AN EVENT : THE PRIMARY GENERATOR

The primary kinematic consists of a single particle which hits the block perpendicular to the input face. The type of the particle and its energy are set in the PrimaryGeneratorAction class, and can changed via the G4 build-in commands of G4ParticleGun class (see the macros provided with this example). The default is monopole 100 GeV

VISUALIZATION

The Visualization Manager is set in the main() for interactive session, the initial parameters of the program are defined in the init_vis.mac macro which then executes the visualisation macro, vis.mac.

The detector has a default view which is a longitudinal view of the box.

The tracks are drawn at the end of event, and erased at the end of run.

HOW TO RUN ?

This example handles the program arguments in a similar way as the basic B4 example. It can be run with the following optional arguments:

 % ./monopole [-m macro ] [-s setupMonopole] [-t nThreads]

The -s option was already explained in the Physics list section. The -t option is available only in multi-threading mode and it allows the user to override the Geant4 default number of threads. The number of threads can be also set via G4FORCENUMBEROFTHREADS environment variable which has the top priority.

Execute program in the 'batch' mode from macro files
```
% ./monopole  -m monopole.in [-s setupMonopole]
```

Execute program in the 'interactive mode' with visualization

% ./monopole [-s setupMonopole]
  ....
Idle> type your commands
  ....
Idle> exit

HISTOGRAMS

The result is five histograms:

Monopole eneregy deposition in current material
dedx for proton
dedx for monopole
range for proton in current material
range for monopole in current material

The histogram is saved in Root file. Limit of bin size can be set with testex/run/binSize (default 5mm). Real size is chosen as a minimal between this and step limit (see Geometry section)