Impact of extinction effects on neutron transmission in solid beryllium metal

Time-of-flight neutron transmission and diffraction measurements were performed on four solid beryllium metal grades using the HIPPO neutron time-of-flight diffractometer equipped with an energy-resolved neutron imaging detector at Los Alamos National Laboratory. Analysis of the extracted total neutron cross sections from the transmission measurements revealed a reduction in the coherent elastic scattering component compared with the values predicted for an ideal polycrystalline material. This reduction could be explained by a lattice-plane-dependent extinction model, which underscores the need to account for extinction effects in neutron transmission measurements. The diffraction measurements rule out texture as the cause of the discrepancies between the calculated and observed cross sections. This study highlights neutron time-of-flight transmission as a sensitive method for investigating extinction phenomena.