| 摘要 |
This disclosure relates to the production of coherent waves of electromagnetic radiation, especially of short wavelengths including X rays, in the form of pulses or continuous beams, utilizing mutually interacting beams of charged particles that include positive ions and electrons. The atoms of which the ions are formed exist in states of excitation energy by virtue of their ionization. The ions capture electrons as the two beams interact, thereby becoming capable of undergoing de-excitation and emitting characteristic electromagnetic radiation. When heavy elements and a high degree of ionization are involved, the radiation so produced can be of high frequency; often X rays. The radiation energies can be of large natural widths which make conditions favorable for the emissions to be composed into a coherent pulse or beam. Despite the extremely short life times of the excited states, the required level of population inversion of the laser medium can be achieved by a specialised approach; population inversion is generated in a limited region on the laser medium, a beam of highly positive ions, by flooding the region with electrons drawn out from an adjacent beam. The population so formed in a region is advanced along the medium, region to region, in synchronization with the progress of the coherent photons. A preferred mode of the invention that generates a coherent X ray pulse of 11.2 keV photons having an energy output of 3.6 J and a power rating 360 GW is described.
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