Abstract: A system and process for the production of nitrogen-13 ammonium ions from a target material in the form of a dilute solution of ethanol in natural water by the reaction of protons with oxygen-16 within the target material. The system includes a device for producing a proton beam which travels along a preselected path and strikes the target material in a target chamber. This target chamber is positioned in the path of the proton beam such that subjection of the target material to the beam produces nitrogen-13 atoms in a predetermined form. These nitrogen-13 atoms are converted in the aqueous solution to ammonium, ions and oxides and are conducted from the target holder to a purification device for collecting a purified product containing such ammonium ions. A cooling system serves to dissipate heat generated during the production of the nitrogen-13 atoms by the reaction of protons with the oxygen. Other solutes for the target material are discussed.