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\page ExampleHadr00 Example Hadr00
\author V.Ivanchenko \n
CERN, Geneva, Switzerland
This example demonstrates a usage of G4PhysListFactory to build
Physics List and G4HadronicProcessStore to access cross sections.
## GEOMETRY
The Target volume is a cylinder placed inside the World volume. Following
UI commands are available to modify the geometry:
```
/testhadr/TargetMat G4_Pb
/testhadr/WorldMat G4_AIR
/testhadr/TargetRadius 10 mm
/testhadr/TargetLength 20 cm
```
By default beam direction coincides with the target axis and is Z axis
in the global coordinate system. The beam starts in the middle of the target.
G4ParticleGun is used as a primary generator. The energy and the type of
the beam can be defined via standard UI commands
```
/gun/energy 15 GeV
/gun/particle proton
```
## PHYSICS
Physics List is defined by its name given in the 3d argument of the of the
run command.
```
./Hadr00 my.macro QGSP_BERT
```
If 3d argument is not set then by the PHYSLIST environment variable.
By default FTFP_BERT Physics List will be instantiated.
## CROSS SECTION
At the end of any run the set of cross sections is built and can be printed
out for a given projectile particle and a target element, which can be
defined via UI commands:
```
/testhadr/particle pi+
/testhadr/targetElm Pb
/testhadr/verbose 1
```
The level verbosity above zero provides printout of the cross section table.
The energy/momentum limits and number of bins can be set via UI commands:
```
/testhadr/nBinsE 900
/testhadr/nBinsP 700
/testhadr/minEnergy 1 keV
/testhadr/maxEnergy 1 TeV
/testhadr/minMomentum 1 MeV
/testhadr/maxMOmentum 10 TeV
```
## VISUALIZATION
The vis.mac file can be used as an example of visualization.
## HISTOGRAMS
All histograms are provided in decimal logarithmic scale (log10(E/MeV)
and log10(p/GeV)) for one projectile particle and one target element.
The element is taken from the Geant4 NIST database, natural isotope
composition is assumed.
Only ROOT histograms are available.