Selection of the discharge-tube material for a nitrogen longitudinal-discharge ultraviolet laser to ensure the maximum average radiation power

A theoretical and experimental analysis was made of the influence of the material of the surface of a discharge tube on the frequency characteristics of a molecular nitrogen laser emitting ultraviolet radiation under conditions when the influence of the translational temperature of the gas could be ignored. The experimental dependences of the average output power on the repetition frequency of the excitation pulses yielded the rate constants of the deactivation of vibrationally excited molecules and the accommodation coefficients of different surfaces. It was found that the discharge tube materials ensuring the maximum average output power and the highest repetition frequency of the excitation pulses in the case of lasers utilizing ultraviolet transitions in nitrogen molecules are substances with the highest accommodation coefficients and thermal diffusivity. These requirements were satisfied best by copper, aluminum, and graphite. The advantages of these materials were utilized in segmented metal discharge tubes.