The Neutron Total Cross Section of ¹²⁹I below 1 keV

Abstract

Although the isotope ¹²⁹I is known to be an important fission product of conventional nuclear power plants, only few measurements describe its properties in the resonance region ^1,)2,)3 mainly because of sample procurement and handling problems. In order to improve nuclear data for nuclear waste transmutation purposes, time-of-flight measurements (TOF) of the total cross section of ¹²⁹I have been performed in the energy range from 0.14eV up to 100keV at the white neutron source GELINA of the Institute of Reference Materials and Measurements (IRMM) in Geel, Belgium.

The neutron resonance shape fitting program REFIT ⁴⁾ was used to determine the energy E₀, the radiative width Γ_γ and the neutron width Γ_n of the resonances.

Keywords:

• TOF technique
• total neutron cross section of¹²⁹I and of¹²⁷I
• resonance parameters of¹²⁹I from shape analysis