We calculate the continuum x-ray emissivity from a bremsstrahlung differential cross section using either the Bethe-Heitler[7] formula, or that from a screened-bremsstrahlung theory using a Thomas-Fermi model for the atom[8]. The cross section is taken to be isotropic in angle between the projectile electron and emitted photon. This cross section is combined with the target density, and local flux density of the electrons to determine the local volume emissivity of the target. Here again, it is straightforward to handle multilayer or compound targets. The results we present here use the Bethe-Heitler bremsstrahlung cross section.