Jobcard switches for the Deuterium target

In section 8.4.1 of ​Oliver Buss' thesis there are details given on the GiBUU deuterium implementation. The aim of this wiki page is to outline jobcard switches, which are necessary to make use of this implementation.

First the target has to be adjusted to Deuterium:

! file: code/density/nucleus.f90
&target
      Target_Z =  1, Target_A =  2
/

To distribute the nucleons in position and momentum space we can choose between two different wave function models:

! file: code/init/deuterium.f90
&deuteriumFermi
      waveFunction_switch=2     ! 1=Bonn, 2=Argonne
/

Next, we need to define a potential to bind the two nucleons. For this we can't use a mean field, because Deuterium represents a too small system. Instead we use a real two-body potential. Using the parallel ensemble technique, the potential V for each nucleon in the jth ensemble is given by \( V=V_\text{2-body}(r_{1,j}-r_{2,j}) \) where \( r_{i,j} \) is the position of the ith nucleon in the jth ensemble. For the full ensemble method, a Deuterium potential is not yet properly implemented. So we choose for the general input and the propagation routines the following switches:

! file: ./inputOutput/input.f90
$input
      delta_T     = 0.025     ! small time step size since the two-body potential 
                              ! is stiff and therefore the propagation is sensitive 
                              ! to too large time steps
      fullensemble=.false.    ! => use parallel ensemble technique
      freezeRealParticles=.false.     
...
/

! file: code/density/density.f90
&initDensity
      densitySwitch = 2         ! 2=analytic
/

! file: code/propagation/propagation.f90
&propagation
      RungeKuttaOrder=2         ! 2=second order Runge-Kutta
/

! file: code/potential/baryonPotential.f90
&baryonPotential
      EQS_Type=7                ! => Two body potential for deuterium
/

In addition to the smaller time step size, we also used a finer grid.

Up to now is probably all you have to change.

Oliver prefers not to use perturbative particles with Deuterium, since there is no unperturbed nucleus left if there is a nuclear reaction in deuterium. So he chooses for his special case

! file: ./inputOutput/input.f90
$input
...
      length_perturbative=1   ! We don't use perturbative particles
...
/

$low_photo_induced
...
      realRun=.true. ! => reaction products are set into real particle vector
/

This may not work if you use another initialization.

Additionally, he used a finer grid,

! file: code/density/density.f90
&initDensity
...
      gridSize  =  8.0, 8.0, 8.0  ! size of grid
      gridPoints=  100, 100, 100  ! number of gridpoints
/

[It is not clear to me, whether this has any influence at all! (KG)]