Cross section for inelastic neutron scattering from Ir at 6 MeV.

Two samples, one of natural iridium and the other of enriched Ir, were irradiated with a monoenergetic neutron beam of energy 6.0 MeV at the Triangle Universities Nuclear Laboratory. The product of the Ir [Formula: see text] Ir reaction was determined by means of measuring X-rays following electron conversion of the isomeric state at 80.

New precision measurements of the 235U(n,γ) cross section.

The neutron capture cross section of (235)U was measured for the neutron incident energy region between 4 eV and 1 MeV at the DANCE facility at the Los Alamos Neutron Science Center with an unprecedented accuracy of 2-3% at 1 keV. The new methodology combined three independent measurements. In the main experiment, a thick actinide sample was used to determine neutron capture and neutron-induced fission rates simultaneously.

Abrupt change in radiation-width distribution for 147Sm neutron resonances.

We obtained the total radiation widths of s-wave resonances through an R-matrix analysis of (147)Sm(n,γ) cross sections. Distributions of these widths differ markedly for resonances below and above E(n)=300 eV, which is in stark contrast to long-established theory. We show that this change, as well as a similar change in the neutron-width distribution reported previously, is reflected in abrupt increases in both the average (147)Sm(n,γ) cross section and fluctuations about the average near 300 eV.