anchor.diff:    nhit    = 0
     fracab  = zero
     mirror  = one
  -
  -!==> SLICE here
  -
  -!- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  +  cRot    = cos_mb(c_rotation)
  +  sRot    = sin_mb(c_rotation)
  +
     do j = 1, nev
   ! SR-GRD (04-08-2005):
   !   Don't do scattering process for particles already absorbed
  
positive.code: !     &                                   .and. mirror.lt.0.) then
  ! changed xp_pencil0(icoll) to xp_pencil0 due to definition mismatch
  ! this has to be solved if necassary and understood
  !                 c_tilt(2) = -1.*(xp_pencil0(icoll)*cos_mb(c_rotation)+    &
  !     &                       sin_mb(c_rotation)*yp_pencil0(icoll))
  !                 c_tilt(2) = -1.*(xp_pencil0*cos_mb(c_rotation)+           &
  !     &                       sin_mb(c_rotation)*yp_pencil0)
  !                 write(*,*) "INFO> Changed tilt2  ICOLL  to  ANGLE  ",  &
  !     &                   icoll, c_tilt(2), j
  !                 changed_tilt2(icoll) = .true.
  
negative.code: !++  First check whether particle was lost before
  !        if (x.lt.99d-3 .and. z.lt.99d-3) then
  !++  First do rotation into collimator frame
      x  =  x_in(j)*cRot + sRot*y_in(j)
      z  =  y_in(j)*cRot - sRot*x_in(j)
      xp = xp_in(j)*cRot + sRot*yp_in(j)
      zp = yp_in(j)*cRot - sRot*xp_in(j)
  !
  !++  For one-sided collimators consider only positive X. For negative
  !++  X jump to the next particle
  