## A FAST ALGORITHM FOR THE CALCULATION OF NEUTRON SELF-SHIELDING FACTORSLNETI/ICEN/DEENInstitute of Nuclear Sciences and Engineering 2685 Sacavém, Portugal Thermal neutron self-shielding factors are calculated for different materials used in reactor dosimetry. The effect of multiple scattering inside the probe is taken into account within a new theoretical formalism recently proposed with application to foils. Here, the method is extended to probes of cylindrical geometry. A fast algorithm is developed for the calculation of the self-shielding based on an approximation equivalent to nearly six collisions inside the probe, which gives quite satisfactory results in the thermal region. KEYWORDS: self-shielding, scattering, thermal neutrons, wires, foils |