Surface modification of lead silicate glass under X-ray irradiation

Radiation-induced changes in the microstructure of lead silicate glass were investigated in-situ under MgKα irradiation in an ultra-high vacuum (UHV) environment by X-ray Photoelectron Spectroscopy (XPS). Lead-oxygen bond breaking to result in pure lead formation was observed. The segregation, growth kinetics and the structure relaxation of lead, plus the corresponding changes of oxygen and silicon on the glass surfaces were all studied by measuring the time-dependent changes in concentration, binding energy, and the full-width at half-maximum. A bimodal distribution of the oxygen XPS signal, caused by bridging and non-bridging oxygens, was found during the relaxation process. All experimental data indicate a reduction of the oxygen, a phase separation of lead from the glass matrix, and the metallization of lead during and after X-ray irradiation.