Abstract: An oxygen diffusion barrier is used to maintain a purity level of lasing gas in a ring laser gyroscope or other gas discharge device. The oxygen diffusion barrier reduces a release of contaminate gases into a cavity of the ring laser gyroscope and/or absorbs the contaminate gases in the cavity. The oxygen diffusion barrier may be formed on walls of the cavity before or after assembly of the ring laser gyroscope. Alternatively, a material may be applied to inside walls of a cathode mounted on a block of the ring laser gyroscope to maintain the purity level of the lasing gas. As a result of maintaining the purity level of the lasing gas, the ring laser gyroscope operates more efficiently.