THE EGS5 CODE SYSTEM

Table B.7: Variable descriptions for COMMON block MEDIA, include file egs5 media.f of the EGS5
distribution.
RLCM Array containing radiation lengths of the media in cm. (Note the name change
necessitated by combining EGS and PEGS.)
RLDU Array containing radiation lengths of the media in distance units established by
DUNIT.
RHOM Array containing density of the media in g/cm 3 . (Note the name change necessitated
by combining EGS and PEGS.)
NMED Number of media being used (default=1).
MEDIA Array containing names of media (default is NaI).
IRAYLM
Array of flags for turning on (=1) coherent (Rayleigh) scattering in various media.
Set in HATCH based on values of IRAYLR.
INCOHM* Array of flags for turning on (=1) use of incoherent scattering function for Compton
scattering angles in various media. Set in HATCH based on values of INCOHR.
IPROFM* Array of flags for turning on (=1) Doppler broadening of Compton scattering energies
in various media. Set in HATCH based on values of IPROFR.
IMPACM* Array of flags for turning on (=1) electron impact ionization in various media. Set
in HATCH based on values of IMPACR.
CHARD* Array of “characteristic dimensions,” or representative size (in cm) of scoring regions
in various media. Set by user code MAIN prior to PEGS5 call to invoke automated
electron step-size selection.
USEGSD* Array of flags indicating (on =1) whether given media uses Goudsmit-Saunderson
multiple scattering distribution. Set by user code MAIN prior to HATCH call (default=0).
Note that in the current implementation, it is a requirement that if one
elects to use this option in one media, one must use it in all media.
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