Electron Paramagnetic Resonance Study on a 28Si Single Crystal for the Future Realization of the Kilogram

In the future realization of the kilogram using the x-ray crystal density method, isotopically enriched silicon crystals grown by the floating zone method are employed. In this paper, we present the electron paramagnetic resonance study on 28 Si single crystal AVO28. We revealed that the concentrations of various kinds of vacancy defects in the crystal are less than ${1\times 10^{12}}\text{cm}^{-3}$ . Consequently, the necessary mass deficit correction due to these vacancy defects is estimated to be less than ${0.4} \mu \text{g}$ for 1 kg AVO28 spheres.