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Example rdecay01

Survey G4RadioactiveDecay process. See Physics Reference Manual, chapter 36. See also http://ie.lbl.gov/decay.html

Geometry construction

It is a simple box which represente an 'infinite' homogeneous medium.

Physics list

PhysicsList.cc defines only G4RadioactiveDecay, G4Transportation processes, and relevant particle definitions. Therefore, once created, particles or ions travel as geantino.

Primary generator

Default kinematic is an ion (Ne24), at rest, at coordinate origin. Can be changed with particleGun commands.

Physics

As said above, all particles and ions behave as geantino, eg. no energy loss.

A flag:

/rdecay01/fullChain (true or false)

allows to limit to single decay or full decay chain (default). In case of full decay chain, G4TrackStatus of ions is set to fStopButAlive in order to force decay at rest.
In case of single decay, G4TrackStatus of secondary ion is set to fStopAndKill.

At each decay, one counts and plots energy spectrum of created particles and ions, and energy-momentum balance of that decay.

Total time of life of decay chain is plotted. Activity is computed.

The command

 /rdecay01/timeWindow

allows to survey activity of each nuclide in a specified time window [t1,t2] : population at t1 and t2, nb of decays within [t1,t2], mean activity. See timeWindow.mac

Few macros are given in example. Debug.mac is to be run in interactive mode.

User data files

Users can redefine RadioactiveDecay and PhotonEvaporation data, via commands:

/grdm/setRadioactiveDecayFile
/grdm/setPhotoEvaporationFile 

Examples of such files are given in subdirectory UserData.
Formats are described in readme
Examples in macros Cf238.mac and No252.mac

example of biasing

macro timeWindowBiased.mac illustrates one of the biasing capabilities of the radioactiveDecay package. Ca47 is forced to decay within 20 days (eg. 1728000 seconds in data file). It is instructive to plot time of life (histo 8) with and without the weight of the track: see line 189/190 of TrackingAction.cc And also to compare with analog decay mode : comment out /grdm/ commands in the macro.

Visualisation

Visualization Manager is set in the main () (see rdecay01.cc). Initialisation of the drawing is done via the commands /vis/.. in the macro vis.mac. This macro is automatically read from the main in case of interactive running mode.

  • e- red
  • e+ blue
  • nu_e white
  • anti_nu_e white
  • gamma green
  • alpha yellow
  • GenericIon grey

How to start ?

  • Execute rdecay01 in 'batch' mode from macro files
    % rdecay01   singleDecay.mac
    
  • Execute rdecay01 in 'interactive mode' with visualization
    % rdecay01
    ....
    Idle>   ---> type your commands. For instance:
    Idle> /control/execute debug.mac 
    ....
    Idle> /run/beamOn 1
    ....                            
    Idle> exit
    

Macros provided in this example:

  • Co60.mac: Co60
  • Gd158.mac: Gd158 excited state
  • No158.mac: read user data file
  • Po212.mac: Po212 excited state
  • Ra228.mac: Ra228 excited state
  • alpha.mac: Po212 alpha decay
  • atomicDeexcitation.mac: plot Auger cascade
  • fullChain.mac: U238
  • neutron.mac: Li10 neutron emission
  • proton.mac: Co53 proton emission
  • singleDecay.mac: Ne10
  • timeWindow.mac: print activity within a given time window
  • timeWindowBiased.mac: force decay within a given time window

Macros to be run interactively:

  • Cf238.mac: read user data file
  • debug.mac: Pb210
  • electronicCapture.mac: Fe55 electronic capture
  • vis.mac: To activate visualization

Histograms

rdecay01 produces several 1D histograms which are saved as rdecay01.root by default.

  • 1 : energy spectrum: e+ e-
  • 2 : energy spectrum: nu_e anti_nu_ev
  • 3 : energy spectrum: gamma
  • 4 : energy spectrum: alpha
  • 5 : energy spectrum: ions
  • 6 : total kinetic energy (Q)
  • 7 : momentum balance
  • 8 : total time of life of decay chain
  • 9 : total visible energy

The histograms are managed by G4AnalysiManager and its Messenger. The histos can be individually activated with the command :

/analysis/h1/set id nbBins  valMin valMax unit 

where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)

One can control the name of the histograms file with the command:

/analysis/setFileName  name  (default rdecay1)

It is possible to choose the format of the histogram file : root (default), xml, csv, by using namespace in HistoManager.hh

It is also possible to print selected histograms on an ascii file:

/analysis/h1/setAscii id

All selected histos will be written on a file name.ascii (default rdecay1)


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