Epithermal NAA:

the Epithermal neutrons are narrowly defined as those having energy in the range of 0.1 to 1.0 eV. In practice the lower end of the neutron energy range used in ENAA is closer to 0.5 eV, which is the Cd cutoff energy (~ 0.55 eV) and the higher end of the range extends through the resonance neutrons up to several keV. Epicadmium neutrons, like thermal neutrons, also induce (n, γ) reactions and delayed gammas are detected for many elements. These neutrons have limited applicability for a number of elements such as Ag, As, Au, Ba, Br, Cs, Eu, Ga, Gd, Hf, Ir, La, Ni, Rb, Sm, Sn, Sr, Ta, Tb, U, W and Yb which can be determined with higher sensitivity.