Control of charge on insulating glass in vacuum by plasma processing

In order to control the charging of insulating glass used in HV vacuum equipment, the effect of H/sub 2/ plasma processing on the glass surface was studied. The electron-beam irradiation method was used to verify the effectiveness of the charging control. Borosilicate glass plates were used as test samples. When the glass was exposed to H/sub 2/ plasma produced by ac (60 Hz) voltage application, the surface resistivity of the glass was decreased, varying with H/sub 2/ plasma processing time. By exposure to H/sub 2/ plasma for 20 min, the surface resistivity was reduced from /spl sim/10/sup 17/ to /spl sim/10/sup 12/ /spl Omega/. Due to the reduction of the surface resistivity, charging of the glass can be controlled to a level below that which could cause surface flashover.