Direct micro-imaging of point defects in bulk SiO2, applied to vacancy diffusion and clustering E. Suhovoy, V. Mishra, M. Shklyar, L. Shtirberg and A. Blank EPL, 90 2 (2010) 26009 Published online: 20 May 2010 DOI: 10.1209/0295-5075/90/26009