The Dudnikov type Penning source has been operated successfully with low work function LaB6cathodes in a cesium‐free discharge. It is found that the extracted H−current density is comparable to that of the cesium‐mode operation and H−current density of 350 mA/cm2have been obtained for an arc current of 55 A. Discharge current as high as 100 A has also been achieved for short pulse durations. The H−yield is closely related to the source geometry and the applied magnetic field. Experimental results demonstrate that the majority of the H−ions extracted are formed by volume processes in this type of source operation.