“…Electron microscope observations of the defects produced in beryllia, BeO, by neutron irradiation have been reported by Chute & Walker (1964), Wilks & Clarke (1964), Elston, Frisby & Labbe (1964) and others. These authors also reported in greater or lesser detail that electron irradiation in the electron microscope could produce visible defect aggregates in electron microscope images and could result in an eva-poration of the beryllia crystals, leaving fibrous remnants with the fibres parallel to the c axis.…”