RF-plasma treatments of surface-conductive alkali-lead silicate glass and microchannel plate devices

RF-plasma treatments of surface-conductive alkali-lead silicate glasses and microchannel plate devices were performed using argon, ammonia and nitroge n gas mixtures. The effects of the different plasma-treatments on the compo sition of the glass surface were studied using Secondary Ion Mass Spectrosc opy (SIMS) and X-ray Photoelectron Spectroscopy (XPS). A surface depletion of rubidium and cesium due to migration into the bulk of the glass and due to sputtering/vaporization of alkali ions from the glass surface was observ ed after the plasma treatments. The use of N-2 and NH3 in the plasma gas re sulted in the incorporation of nitrogen into the glass surface up to a dept h of similar to 100 Angstrom. The effect of the plasma treatments on the wa ter adsorptivity of actual microchannel plates was studied using Temperatur e Programmed Desorption (TPD). The TPD results showed that the argon plasma treatments helped in improving the short-term water adsorptivity propertie s of the microchannel plate devices, but long-term (> 6 months in air) bene fits were lost. (C) 1999 Published by All rights reserved.