4.3.12 SUBROUTINE ZDLPAR(EGAMMA, ATMNB, LAMBDA) : Lambda for PAiR-production

This routine finds the mean free path (LAMBDA) until e+e- pair- production occurs by a photon with a given energy.

ARGUMENTS:

INPUT :

    EGAMMA : The energy of the photon.
    ATMNB : Atom-number of the material

OUTPUT :

    LAMBDA : The mean free path, in radiation lengths. -ve if below
             cut-off

IMPLICIT INPUTS:

    none.

IMPLICIT OUTPUTS:

    none

CALLED BY :

ZDPAIR, generate PAIR production (see 4.3.10).

CALLED ROUTINE(S):

none

SIDE EFFECTS:

none

AUTHORS:

M. Berggren, UFRJ (adopted from the anonymous SXPPAR in DELSIM)

CREATION DATE:

03-apr-1996