Abstract: A neutron generating system comprising a hermetically sealed housing containing an ionizable gas and a ring anode and target cathode of a Penning ion source. The housing is provided with a recess axially oriented relative to the ring anode and target cathode and adapted to accept a removable samarium/cobalt magnet such that degassing and sealing of the housing can be performed in the absence of the permanent magnet. The cathode target is an OHFC copper rod of substantially the same cross-sectional area as the target with one polished end of the rod containing a titanium film within the housing to serve as the target and the other end of the rod extending out of the housing such as to remove thermal energy from the target during operation. An ion screen between the anode ring and cathode target containing an axially positioned gridded aperture provides a broad ion beam of reduced power per unit area.