"Spectral Cross-section" is the cross-section for a process in which the energy of the ejected or scattered particle is in an interval of energy, divided by the range $dE$ of this interval.
Applicable units are those of quantitykind:SpectralCrossSection
http://en.wikipedia.org/wiki/Cross_section_(physics)
$\sigma = \int \sigma_E dE$
http://www.iso.org/iso/catalogue_detail?csnumber=31895