 subroutine sibyll_ini
      CALL PAR_INI   ! some parameteres are fixed
      CALL JET_INI   ! compute cross sections
        !   and table of probability for the production of
        !   multiple soft and hard interactions
        !   output --> /S_CCSIG/  contains
        !    h-p, h-Air x-sections, and cumulative prob. of
        !    of NS soft and NH hard interactions

      CALL ZSAMPLE_INI  ! structure func.
      CALL BLOCK_INI    ! some param
      CALL NUC_GEOM_INI  ! .Initialize all nucleus profiles 2<=A<=56
      CALL SIG_AIR_INI  ! init of p,pi,K-air xsec and mfp
          SIB_SIGMA_HP  ! hp int. h=p,n,pi,K
          SIG_H_AIR     ! convert hp->h-air.  GLAUBER
                      ! is used but it can treat target of  4<A<18.


      SUBROUTINE SIBNUC (IAB, IAT, SQS)
   IAB(A) IAT(A') collsion generator
   SQS  roots of A/n A'/n
      SUBROUTINE NUC_NUC_INI
       init for A-A' col.