Novel MgO/SiO2 double protective layers to prevent Ag mirror degradation S.-J. Choi, K.-H. Kim, J.-H. Jo, S.-J. Kwon, S. Cho and H. Oh Eur. Phys. J. Appl. Phys., 51 1 (2010) 10501 Published online: 17 June 2010 DOI: 10.1051/epjap/2010063