Ultimate performance of a superconducting quantum detector A. Semenov, A. Engel, K. Il'in, G. Gol'tsman, M. Siegel and H.-W. Hübers Eur. Phys. J. AP, 21 3 (2003) 171-178 Published online: 27 February 2003 DOI: 10.1051/epjap:2003009