Sampling of the multiple scattering angle

CALL GMULTS GMULTS is the steering routine for the sampling of the multiple scattering angle when the variable IMULTS in common /GCPHYS/ is 1 or 2. This variable can be controlled by the MULT data record. The routine decides if the material-dependent constant OMC computed by GMOLI during initialisation has to be corrected due to its dependence on $\beta$ and $Z$_inc , and selects Molière theory (GMOLIE) or single Coulomb scattering (GMCOUL). It updates the direction of the particle in the array VECT (COMMON GCTRAK). It is called by the tracking routines GTELEC, GTHADR, GTHION and GTMUON.

CALL GMOLIO (AC,ZC,WMAT,NLM,DENS,BETA2,CHARG2,OMC*)

BETA2

REAL $\beta 2$ of the particle;

CHARG2

REAL charge squared of the particle in electron charge unit ($Z$_inc² in the following).

All the other arguments are routine GMOLI. GMOLIO re-evaluates the material-dependent constant OMC. It is called by GMULTS, if needed.

CALL GMOLIE (OMEGA,BETA2,DIN*)

OMEGA

REAL $\Omega$₀ of the Molière theory;

BETA2

REAL $\beta 2$ of the particle;

DIN

REAL array of dimension 3 containing the new direction cosines with respect to the original direction of the particle.

CALL GMOL4 (Y*,X,VAL,ARG,EPS,IER*)

Y

REAL value of the interpolated function;

X

REAL value at which the function should be interpolated;

VAL

REAL array of four values of the function to interpolate;

ARG

REAL array of four values of the argument of the function to which the values contained in VAL correspond;

EPS

REAL required precision for the interpolation;

IER

INTEGER error flag;