INFLUENCE OF BORON ON CLUSTERING OF RADIATION DAMAGE IN GRAPHITE .3. PHYSICAL PROPERTY MEASUREMENTS

X-ray lattice parameters and electrical resistivity, magnetoresistivity and Hall coefficient have been measured as a function of boron concentration in graphite single crystals. These measurements are consistent with boron forming a substitutional solid solution up to a concentration of 1% boron in graphite. After irradiation to a dose of 7·6 × 1019 n/cm2 (Ni) at 150°C, 650°C or 900°C, the electronic property changes were correlated with the effect of addition of boron in solid solution to give an estimate of the defect concentration. X-ray diffraction of the crystals irradiated at 650°C showed that the Bragg reflections had both a diffuse and a sharp component, the intensity of the diffuse component increasing and of the sharp component decreasing with increasing boron content. The lattice parameter change, as measured by the shift in position of the sharp component of the reflection, was associated with vacancies, isolated or in small clusters up to a boron concentration of 4 × 10−4. © 1969 Taylor & Francis Group, LLC.