Effect of the rate of rise in discharge current on the output of a 46.9-nm soft X-ray laser based on capillary discharge

Abstract

The rate of rise in discharge current (dI/dt) is an important parameter in an X-ray laser pumped by fast capillary discharge. The effect of this parameter on the energy of an argon plasma-based 46.9-nm soft X-ray laser pulse has been experimentally studied. It was found that an X-ray laser pulse with ~2 μJ energy, which can be obtained at a discharge current of ~40 kA with dI/dt value of ~7.1 × 1011 A/s, can also be obtained at a much lower peak current of ~26 kA if the quarter period (T/4) of the discharge current is made shorter to achieve a comparable dI/dt value. For a fixed T/4, the laser energy could be enhanced from 2 to 4 μJ for an increase in the dI/dt value from 7.1 × 1011 to 1.3 × 1012 A/s by increasing the peak current from 26 to 44 kA. It was also observed that for a fixed dI/dt, mere increase in the discharge current does not increase the laser energy.