Structural Analysis of a Completely Amorphous²³⁸Pu-Doped Zircon by Neutron Diffraction

The structure of a completely amorphous zircon was determined by time-of-flight neutron diffraction at Argonne's Intense Pulsed Neutron Source (IPNS). The sample of metamict zircon (ZrSiO₄), initially doped to 8.85 weight percent ²³⁸Pu, had been completely amorphized by alpharecoil damage since its synthesis in 1981 at the Pacific Northwest National Laboratory (PNNL). The measured diffraction structure factor, S(Q), indicated a completely amorphous sample, with no signs of residual zircon microcrystallinity. The pair distribution function obtained indicated that the structure was that of an oxide glass, retaining the Si-O, Zr-O, and O-O bond lengths of crystalline zircon.