GEANT321/gphys/gmgaus.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:21:26  cernlib
   6 * Geant
   7 *
   8 *
   9 *    EX GMUL
  10 #include "geant321/pilot.h"
  11 *CMZ :  3.21/02 29/03/94  15.41.22  by  S.Giani
  12 *-- Author :
  13       SUBROUTINE GMGAUS(BETA2,DIN)
  14 C.
  15 C.    ******************************************************************
  16 C.    *                                                                *
  17 C     *       Compute multiple scattering angles for a particle        *
  18 C.    *       with parameters VECT in common /GCTRAK/                  *
  19 C.    *       in current medium described in common /GCMATE/           *
  20 C.    *       Output angles overwrite VECT                             *
  21 C.    *                                                                *
  22 C.    *    ==>Called by : GMULTS                                       *
  23 C.    *       Authors    R.Brun, M.Maire, G.Lynch  *********           *
  24 C.    *                                                                *
  25 C.    ******************************************************************
  26 C.
  27 #include "geant321/gctrak.inc"
  28 #include "geant321/gcphys.inc"
  29 #include "geant321/gcmulo.inc"
  30 #include "geant321/gconsp.inc"
  31       DIMENSION DIN(3),RNDM(3)
  32 *
  33 *     ------------------------------------------------------------------
  34 *
  35 * *** Computes mean deviation angles in radian
  36 *
  37 *     Scattering corresponding to OMEGA0 = 4E4 scatters and F=0.98.
  38 *
  39       SIGMA  = 2.557 * CHCMOL*SQRT(STMULS)/(GETOT*BETA2)
  40 *
  41       CALL GRNDM(RNDM,3)
  42       PHI = TWOPI*RNDM(2)
  43       THETA  = SIGMA*SQRT(-2.*LOG(RNDM(1)))
  44       IF(RNDM(3).GT.0.5)THETA=-THETA
  45       SINT   = SIN(THETA)
  46       DIN(1) = SINT*SIN(PHI)
  47       DIN(2) = SINT*COS(PHI)
  48       DIN(3) = COS(THETA)
  49 *
  50       END