CORRFACT

    allows to alter material density for dE/dx and nuclear processes on a
    region-by-region basis

    See also ASSIGNMAt, COMPOUND, LOW-MAT, MATERIAL, MAT-PROP

     
WHAT(1)
: > 0.0 : density scaling factor for charged particle ionisation
                      processes (dE/dx, delta ray production, Möller and Bhabha
                      scattering)
              = 0.0 : ignored
              -2 < 
WHAT(1)
 < 0:
                      |
WHAT(1)
| assumed relative to 
WHAT(2)
, the final
                      density correction factor will be |
WHAT(1)
| X 
WHAT(2)
                =<-2: reset to default (1)
              
Default
: 1.0

     
WHAT(2)
: > 0.0 : density scaling factor for all other processes
              = 0.0 : ignored
              < 0.0 : reset to default
              
Default
: 1.0

     
WHAT(3)
: not used

     
WHAT(4)
: lower index bound (or corresponding name) of regions where the
              scaling factors shall apply
               "From region 
WHAT(4)
..."
              
Default
: 2.0

     
WHAT(5)
: upper index bound (or corresponding name) of regions where the
              scaling factors shall apply
               "...to region 
WHAT(5)
..."
              
Default
: 
WHAT(4)

     
WHAT(6)
: step length in assigning region numbers
               "...in steps of 
WHAT(6)
"
              
Default
: 1.0

     
SDUM
   : not used

     
Default
 (option CORRFACT not requested): no density scaling factors are
             applied


     
Note:
      1) Option CORRFACT is mainly used in connection with voxel geometries
         derived from a CT scan, where particle transport is done often in an
         equivalent material (e.g., water), but accounting for the density
         variations provided by scan at the voxel level. While this approach
         is reliable for what concerns ionisation, other reactions, which do
         not scale with density, must be simulated for the actual material
         composition.

      2) Only density scaling factors in the range [2/3 , 3/2] are allowed.

     Example, in a number-based input:

 *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
 * Multiply density by a 0.85 factor for what concerns atomic processes
 * in regions 7, 8, 9, 10, 11, 12
 CORRFACT        0.85       0.0       0.0       7.0       12.

     The same example, in a name-based input, supposing that the geometry is
     made of 12 regions:
 CORRFACT        0.85       0.0       0.0  The7thRg  @LASTREG
 * Note the use of the name @LASTREG to indicate the maximum number of regions
 * in the problem

Previous Index Next