Nuclear-pumped Gas Lasers Research Articles

Active Element Diameter and Uranium Coating Thickness Effect on Nuclear-Pumped Gas-Laser Efficiency

A comparative experimental study is performed of the lasing characteristics of a laser operating on the 2.03 μm transition of atomic xenon with direct, uranium fission fragment, pumping of the active medium in the form of a mixture of the gases He, Ar, and Xe in cylindrical active elements of two types, differing by the diameter and thickness of the uranium coating. It is shown that a three-fold reduction of the diameter and coating thickness of the active element results in a 1.5-fold increase of the laser efficiency in terms of energy. One possible explanation of this effect is examined: a source of internal losses of laser radiation present in the active medium due to scattering by radial acoustic gas-density waves excited by the pump pulse.

A 500-J nuclear-pumped gas laser

A 500-J pulsed gas laser (laser module) pumped by uranium nuclear fission products has been created, which operates on xenon 5d[3/2]1 → 6p[3/2]1 transition with a wavelength of 2.03 μm. Experiments have been performed on a BARS-5 + RUN-2 complex comprising a fast aperiodic self-quenching reactor and a neutron multiplier reactor. A specific laser radiation energy in experiments achieved ∼32 J/dm3 at an efficiency of 3% (ratio of the laser output pulse energy and the energy transferred from fission fragments to gas medium).

Analysis of lasing threshold of a nuclear-pumped gas laser depending on the lasing medium residence time in the laser module case

It is shown experimentally that an increase in the lasing mixture residence time in the case of a laser module over 60–120 min prior to an experiment elevates the lasing threshold and deteriorates the energy parameter of the laser. The worsening of the energy parameters of the laser may be due to accumulation of impurity gases. It is shown that the presence of impurities affects the working characteristics of the laser media under investigation to various extents.

Lasing threshold of a nuclear-pumped gas laser versus the residence time of the lasing medium inside a laser unit

It is shown experimentally that, when the residence time of the lasing mixture in a laser unit increases from 60 to 120 min, the lasing threshold grows and the energy parameters of the laser degrade. The latter effect is associated with impurity gas accumulation. Impurities are found to variously influence the operating characteristics of the lasing media considered in this paper.

Generation on 3F4-3H6 transition in Tm3+ ion upon direct excitation of 3F4 state by nuclear pumped gas laser

The possibility of lasing in a YAP:Tm3+ crystal with 3F4 level of the Tm3+ ion directly pumped by narrowband radiation of a gas laser operating in the middle IR range has been studied. The efficiency of the pumped energy conversion into spontaneous emission on the 3F4-3H6 transition in the Tm3+ ion was within 65–75%. The efficiency of generation with respect to the absorbed pumping energy was ∼4%.

Energy deposition in helium-3-based nuclear-pumped gas lasers

The amount and distribution of energy deposition in the cylindrical cells of nuclear-pumped lasers excited by products of the 3He(n, p)3H nuclear reaction are investigated theoretically. Calculation results for three neutron energy distributions, as well as the energy deposition distributions inside the laser cell at helium-3 initial pressures of 1 and 2 atm, are presented.

Optical nonuniformities in nuclear-pumped lasers with plane uranium layers

Optical nonuniformities in the nuclear-pumped gas lasers are calculated. The nonuniformities are formed due to inhomogeneous energy deposition by the fission fragments from thin plane uranium layers that irradiate the laser active gas. The results of calculations agree with experimental data.

Optical nonuniformities in nuclear-pumped cylindrical lasers

The optical nonuniformities, formed as a result of the effect of the inhomogeneous energy deposition by the fission fragments irradiating the laser-active gas from thin uranium-containing layers, were calculated for cylindrical nuclear-pumped gas lasers. The results of the calculations agree with the experiment.

Nuclear-pumped gas lasers at temperatures up to 800˚C

This article describes the design of a laser setup excited by 3He(n, p)3H reaction products and intended for investigations of the laser characteristics of 3He mixtures with metal vapors or other gases at temperatures up to 800˚C. This setup could also be used to study the effect of the medium heating on the characteristics of nuclear-pumped gas lasers.

Ultimate efficiency of nuclear-pumped gas lasers

We suggest several cascade lasing schemes: (1) cascade of laser transitions between atom (ion) excited levels when the lower laser level of one laser transition is simultaneously the upper laser level of another transition located below; (2) successive lasing, first, on ion transitions, then after ion recombination on atom transitions; (3) while using multicomponent mixtures, successive lasing on atoms (ions) of separate components. These possibilities are discussed in terms of specific lasers, some of which have been studied experimentally.

Nuclear Pumped Gas Lasers

Gas lasers pumping by nuclear energy, discussing heavy particle interactions, threshold densities, population inversion, etc