Spectra of the optical transmission and ion-induced photon emission (IIPE) of silica glass were measured during implantation of 60 keV Cu-ions at ion fluxes from 1 to 75 mu A/cm(2) up to a fluence of 2 x 10(17) ions/cm(2), aimed at monitoring the formation of Cu nanoparticles. The precipitation threshold of Cu atoms is flux-dependent. At fluxes from 1 to 10 mu A/cm(2), the formation of nanoparticles is efficient up to fluences of 2 x 10(17) ions/cm(2). The efficiency of IIPE of Cu+ solutes in silica glass (band at 2.25 eV) is proportional to a total concentration of Cu solutes. In a single-phase region (solid solution of Cu atoms), the efficiency of IIPE of Cu+ solutes is flux-independent. In a two-phase region (solid solution and Cu nanoparticles), the dynamic balance between the nanoparticles and Cu solutes determines the flux-dependent behavior of the efficiency of IIPE. (c) 2004 Elsevier B.V. All rights reserved.