Investigation of ¹²⁷I(n,2n)¹²⁶I and ²³Na(n,2n)²²Na Reactions Using ²⁵²Cf Neutron Source

This work deals with ²³Na(n,2n)²²Na and ¹²⁷I(n,2n)¹²⁶I reactions in the ²⁵²Cf spontaneous fission neutron source. ²⁵²Cf neutron source with approximate emission of 6·× 10⁸ n/s was employed for the irradiation of sodium iodide. The spectrum-averaged cross sections (SACS) were then inferred from experimentally determined reaction rates and compared with calculations in MCNP6 using various nuclear data libraries. The experimental reaction rates were derived from the net peak areas (NPAs) measured using the high purity germanium spectroscopy. The measured SACS for the ²³Na(n,2n)²²Na reaction in the ²⁵²Cf spectrum was determined as equal to (8.98±0.32)·× 10⁻⁶ b. The resulting SACS for the ¹²⁷I(n,2n)¹²⁶I reaction in the ²⁵²Cf spectrum was derived as (2.044±0.0072)·× 10⁻³ b. These experimental data can be used for nuclear data libraries validation and to specify high energy tail of the ²⁵²Cf neutron spectrum.