Dependence of the Ratio between the Resonance Integral and Thermal Neutron Cross Section on the Deviation of the Epithermal Neutron Spectrum from the 1\E Law

In k0- Neutron Activation Analysis (k0-NAA), the conversions from the tabulated Q(0) (ratio of the resonance integral to thermal neutron cross-section) to Q(0) (alpha) (alpha is the shape factor of the epithermal neutron flux, indicating the deviation of the epithermal neutron spectrum from the ideal 1/E shape) are calculated using a developed program written in FORTRAN. The calculation was carried out for most elements that can be detected by neutron activation using different values of the parameter (alpha) ranging from -0.1= alpha = +0.1. The obtained data were used to study the dependence of alpha upon the irradiation position factor in (k0-NAA) equation for some selected isotopes having different resonance energy and Q(0) values. The result showed that, the irradiation factor is affective mainly for low thermal to epithermal flux ratio f especially for Q(0) value greater than 50. So consequently determining the irradiation parameters alpha is not needed for irradiation positions with high thermal neutron densities. But for high f values the irradiation position factor should be taken into account. On the other hand the developed program can be applied to calculate Q(0) (alpha) directly for different values