[en] Experimental results are reported on the production of ion beams in a ribbon ion diode 80 cm long with self-insulation and an ion beam density in the range 20--60 A/cm². The diode operates at 0.25--0.4 of z/sub v/, where z/sub v/ is the vacuum impedance, with an ion beam density which increases in the drift direction. The beginning of the production of the ion beam is correlated with the formation of a magnetized electron sheet. The ion spectrum has a bimodal structure, with a high concentration (> or approx. =30%) of carbon ions. The efficiency of the diode is (27--33)%, in agreement with theoretical predictions. The simplicity of this diode and the good reproducibility of the characteristics of the ion beams which it generates make this diode promising for use in transverse pumping of long active media