DYNAMIC EFFECTS IN ENERGETIC PARTICLE-INDUCED LUMINESCENCE OF SIO2

Dynamical measurements of ion-induced luminescence and in-reactor lumi nescence of SiO2 glass have been performed. First the dynamic effects of the ion-induced luminescence are compared between D+ and He+ ion ir radiations. and then the time evolution of the in-reactor luminescence change with neutron fluence is compared with that observed in the ion -induced luminescence. Finally, the origin of the luminescence center is discussed. The luminescence spectra of silica glasses induced by D and He+ irradiation have been found to be very similar to cathodolumi nescence originating from the centers associated with oxygen vacancies , and the intensity is proportional to the deposited energy by electro n excitation irrespective of the incident ion species. The luminescenc e intensity changes with ion fluence, first increasing, then reaching a maximum and finally decreasing to the nearly steady value after prol onged irradiation. When the fluence is converted to displacement per a tom (dpa) value, changes of the luminescence intensity under D+ and He irradiations are very similar. from dynamical change of the luminesce nce intensity, the first increase of the Luminescence intensity is att ributed to the increase of newly produced point defects or to an oxyge n deficiency due to atomic displacement. The observed decrease is attr ibuted to the association of the point defects, for example, formation of segregated Si or more complex defects. In-reactor luminescence als o reveals an intensity increase caused by neutron; induced displacemen t. The present work clearly demonstrates that dynamic measurement of t he ion-induced luminescence can give detailed information on the proce sses of defect formation in optically transparent materials. (C) 1998 Elsevier Science B.V.. All rights reserved.