Applicability of the 1/E1+α epithermal spectrum representation and the effective resonance energy\bar E_r in NAA

The practical applicability of the 1/E¹⁺ epithermal spectrum representation and of the effective resonance energy in NAA is investigated. Attention is paid to fundamental considerations such as definitions and approximations, error propagation functions, uncertainty statements, reliability of nuclear data and formal dimensioning problems. As to the latter, it is concluded that the applicability of the -concept is not dependent on the choice of a reference energy. The usefulness of the parameters and in NAA is demonstrated by new experimental evidence obtained from and Q₀ determinations in three different reactors: the WWR-M reactor (Budapest, Hungary), the THETIS reactor (Gent, Belgium) and the DR-3 reactor (Risø, Denmark).