Universal curve of the thermal neutron self-shielding factor in foils, wires, spheres and cylinders

The interpretation of the sample activation in a nuclear reactor requires the knowledge of two corrective parameters: the thermal neutron self-shielding factor, G th, and the resonance neutron self-shielding factor, G res. The authors established a universal curve of G res for isolated resonances and various geometries. The present paper deals with the description of G th in foils, wires, spheres and cylinders by means of a universal curve on the basis of a dimensionless variable which includes the physical, nuclear and geometrical properties of the sample. The universal curve is in good agreement with the experimental and calculated values obtained from the literature.