CHARACTERISTICS OF THE ACTIVE ELEMENT OF A NUCLEAR-PUMPED CADMIUM-VAPOR LASER

摘要

The influence of the active-element characteristics on the efficiency of a cadmium-vapor laser pumped by uranium fission fragments was studied experimentally. The 441.6 nm laser radiation of the cadmium ion was studied. An aluminum tube with diameter 15 mm and an inner coating of U3O8 with thickness 3 mg/cm(2) served as the active element. The neutron source was the BARS-6 pulsed, fast, aperiodic, self-extinguishing reactor. A comparison of the efficiency of the laser with similar data previously obtained under the same conditions for a 48 mm in diameter active element with a 10 mg/cm(2) thick uranium metal coating shows that a three-fold reduction of the diameter of the active element and uranium coating thickness results in a 2.5-fold increase of the laser efficiency. This confirms the hypothesis of internal losses of laser radiation in the active element of a fission-fragment pumped laser which are due to the scattering of light by transverse sound waves of the gas density which appear during a pumping pulse because of the radial non-uniformity of the energy input.