This works deals with a laboratory model 100 A-class hollow cathode with a sintered lanthanum hexaboride (LaB6) emitter for high-power Hall thrusters. The cathode has been fired up to 70 A with xenon as working gas. The cathode architecture, test setup , ignition procedure and power consumption are described first. The second part of this contribution comments on the emitter temperature, the current-voltage characteristics and the discharge modes obtained for discharge currents in the 30-70 A range and mass flow rates in the 15-30 sccm range. Finally we present electron temperatures and densities measured in the cathode plasma plume by means of incoherent Thomson scattering.