title: Note: discharging fused silica test masses with ionized nitrogen.
abstract: We have developed a technique for discharging fused silica test masses in a gravitational-wave interferometer with nitrogen ionized by an electron beam. The electrons are produced from a heated filament by thermionic emission in a low-pressure region to avoid contamination and burnout. Some electrons then pass through a small aperture and ionize nitrogen in a higher-pressure region, and this ionized gas is pumped across the test mass surface, neutralizing both polarities of charge. The discharge rate varies exponentially with charge density and filament current, quadratically with filament potential, and has an optimal working pressure of ∼8 mT. Adapting the technique to larger test mass chambers is also discussed.
authors.affiliation: Department of Physics and Astronomy, Trinity University, San Antonio, Texas 78212, USA. dugolini@trinity.edu
authors.forename: D
authors.initials: D
authors.lastname: Ugolini
authors.forename: Q
authors.initials: Q
authors.lastname: Funk
authors.forename: T
authors.initials: T
authors.lastname: Amen