[en] Results of the first phase of an experimental investigation of the minimum e-beam current density requirements for repetitively pulsed XeF lasers with 10 to 100-mJ pulse energy are presented. Measurements were made in the self-sustained and e-beam preionized mode of operation. The e-beam preionized experimental results were similar to those obtained with uv preionization at other laboratories, indicating that ionization phenomena (rather than photodissociation) are dominant in both experiments. Multi-pulse e-beam experiments in a single gas fill resulted in rapid gas degradation, possibly due to electron bombardment of insulated surfaces with subsequent evolution of gaseous impurities