A plasma source suitable for repetitive operation, going beyond single shot experiments for research into soft x‐ray lasers, is reported. Successful operation of an ultrafast, small‐diameter, highly uniform z pinch has been achieved at currents of 35–50 kA, for a variety of gases and a large range of mass densities. Due to an efficient preionization of the working gas, a high‐temperature and a high cooling rate of the plasma column are obtained. The plasma is less than 1 mm in radius, over 30 mm long, and over 1018 cm−3 ion density. A soft x‐ray recombination laser experiment for the λ≊182 Å Balmer‐alpha‐like transition in C vi is proposed.