Abstract
The development of soft x-ray lasers collisionally pumped by a relatively long prepulse and short main pulse has markedly improved the effectiveness of these devices. As a result it is possible to envisage their use in a well equipped university laboratory. In this note we break down the various elements of the interaction and pumping into their simple components in order to see how relatively simple analytic concepts can be used to identify the best mode of operation. However detailed simulation is still required to identify the actual experimental operating conditions. The scaling results are compared with simulation, confirming the value of this analysis.