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FLUKAFIX


     Sets the size of the step of muons and charged hadrons to a fixed
     fraction of the kinetic energy in different materials

     See also EMFFIX, MULSOPT, STEPSIZE

     
WHAT(1)
= fraction of the kinetic energy to be lost in a step (cannot be > 0.2)
Default
: if option DEFAULTS is used with
SDUM
= ICARUS, the default is 0.02. With
SDUM
= HADROTHErapy or PRECISIOn, the default is 0.05. If
SDUM
= CALORIMEtry, the default is 0.08. With any other
SDUM
value, or if DEFAULTS is missing, the default is 0.1. * Start_Devel_seq
WHAT(2)
= "epsilon" parameter used to check the finite size of the nucleus when the nuclear form factor is not invoked by the multiple scattering algorithm (see Note 3 below) For code development only, do not change!
Default
= 0.15
WHAT(3)
= high-energy limit for the fraction of energy to be lost in a step (the fraction is given by
WHAT(3)
times
WHAT(1)
) For code development only, do not change!
Default
= 0.012 * End_Devel_seq * Start_Prod_seq
WHAT(2)
,
WHAT(3)
: reserved for code development * End_Prod_seq
WHAT(4)
= lower index bound (or corresponding name) of materials where the specified energy loss per step is to be applied (From material
WHAT(4)
...)
Default
= 3
WHAT(5)
= upper index bound (or corresponding name) of materials where the specified energy loss per step is to be applied (... to material
WHAT(5)
...)
Default
=
WHAT(4)
WHAT(6)
= step length in assigning indices (...in steps of
WHAT(6)
)
Default
= 1
SDUM
: not used
Default
(option FLUKAFIX not given): the defaults listed above apply
Notes:
1) Usually there is no need for changing the general default value of 10% (0.1) for
WHAT(1)
* Start_Devel_seq 2) The input value is actually applied as such only at intermediate energies (between about a few tens of MeV and 1 GeV): at low energies it is slowly increased to twice the requested value, while at high energies it decreases to a limit controlled by
WHAT(3)
, usually about one hundredth of the input value. 3) The "epsilon" parameter controls the accuracy of the multiple scattering algorithm by limiting the step. In most cases the length of the step is practically limited anyway by the hadron interaction length, so the "epsilon" default value is of little importance and does not need to be changed. However, in some problems of large dimensions, especially when transporting muons, a small value of epsilon can slow down the calculations without necessity. In such cases,
WHAT(2)
can be safely set = 1000.0 * End_Devel_seq * Start_Prod_seq 2) The input value is actually applied as such only at intermediate energies (between about a few tens of MeV and 1 GeV): at low energies it is slowly increased to twice the requested value, while at high energies it decreases to a limit usually about one hundredth of the input value. * End_Prod_seq Example (number based):
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....
FLUKAFIX 0.03 0. 0. 21. 0. 0.
* The maximum fractional energy loss for hadrons and muons is set to
* 3 percent in material 21.
The same example, name-based: FLUKAFIX 0.03 0. 0. CALCIUM 0. 0.

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