The k0 and Q0 values for 94Zr(n,)95Zr(E
= 724.2+756.7 keV) and 96Zr(n,
)97Zr(
–) 97mNb (E
= 743.4 keV) were re-investigated. The aim was to further improve the reliability of the neutron spectrum characterization (f and
monitoring) in k0-NAA, based on "bare monitor" methods with the use of these Zr radionuclides. So as to achieve this goal, experimental determinations were performed in three reactor centers: KFKI AEKI, Budapest (WWR-M reactor); INW, Gent (THETIS reactor); SCK·CEN, Mol (BR1 reactor). The results were: Q0(94Zr) = 5.306; Q0(96Zr) = 251.6; k0(95Zr, 724.2+756.7 keV) = 2.000E-4; k0(97Zr/97mNb, 743.4 keV) = 1.237E-5. This means that the newly evaluated k0-values are about 4.7% lower than the formerly reported ones. It is also emphasized that the 97Zr half-life is 16.74 hours, contrary to the
1% higher values usually reported.