A method for inducing chemical reactions using X-ray radiation, comprising: (a) generating an X-ray irradiation volume within the interior of a reaction vessel by introducing X-ray radiation into the interior of the reaction vessel; (b) introducing at least a feedstock reactant into the X-ray irradiation volume; (c) introducing at least one reactant, other than the at least a feedstock reactant, into the X-ray irradiation volume via one or more X-ray shielded injector pipes that extend into the X-ray irradiation volume; each of the one or more X-ray shielded injector pipes having a main X-ray shielded path extending along a majority of a length of the X-ray irradiation volume and having a plurality of injector apertures; i) each injector aperture extending transversely outwardly from the main X-ray shielded path and opening into the X-ray irradiation volume to allow said at least one reactant to reach the X-ray irradiation volume; ii) said plurality of injector apertures including injector apertures that are spaced along said main X-ray shielded path for a majority of the length of the X-ray irradiation volume; and (d) inducing selective reactions to occur in said X-ray irradiation volume through control of the fluence and energy of said X-ray radiation so as to totally or partially ionize, within said X-ray irradiation volume, all or part of the at least a feedstock reactant, the at least one reactant other than the at least a feedstock reactant, and any subsequently created intermediate reactant or reactants. (a) generating an X-ray irradiation volume within the interior of a reaction vessel by introducing X-ray radiation into the interior of the reaction vessel; (b) introducing at least a feedstock reactant into the X-ray irradiation volume; (c) introducing at least one reactant, other than the at least a feedstock reactant, into the X-ray irradiation volume via one or more X-ray shielded injector pipes that extend into the X-ray irradiation volume; each of the one or more X-ray shielded injector pipes having a main X-ray shielded path extending along a majority of a length of the X-ray irradiation volume and having a plurality of injector apertures; i) each injector aperture extending transversely outwardly from the main X-ray shielded path and opening into the X-ray irradiation volume to allow said at least one reactant to reach the X-ray irradiation volume; ii) said plurality of injector apertures including injector apertures that are spaced along said main X-ray shielded path for a majority of the length of the X-ray irradiation volume; and i) each injector aperture extending transversely outwardly from the main X-ray shielded path and opening into the X-ray irradiation volume to allow said at least one reactant to reach the X-ray irradiation volume; ii) said plurality of injector apertures including injector apertures that are spaced along said main X-ray shielded path for a majority of the length of the X-ray irradiation volume; and (d) inducing selective reactions to occur in said X-ray irradiation volume through control of the fluence and energy of said X-ray radiation so as to totally or partially ionize, within said X-ray irradiation volume, all or part of the at least a feedstock reactant, the at least one reactant other than the at least a feedstock reactant, and any subsequently created intermediate reactant or reactants.