The generation of a plasma by fission‐fragment ionization of noble gases is reported. The experimental data consist of steady‐state current‐voltage (I‐V) characteristics obtained with ceramic‐metal ionization tubes which were operated in the high neutron flux region of a nuclear reactor. The observed dependence of I on V½ for applied potentials <100 V is shown to be consistent with the theory that the predominant charge loss in the plasma is volume recombination of diatomic ions and electrons. The ion generation rate is calculated from the energy loss rate of the fission fragments in the gas and I‐V characteristics for the noble gases are computed. These characteristics, which do not contain any adjustable parameters, are in agreement with the experimental data within±10%. Data are presented for neon, argon, xenon, and neon‐argon (Ar/Ne=10−3) for gas pressures in the range 30 to 400 Torr. Typically, for a gas pressure of 240 Torr and a neutron flux of 1013 cm−2·sec−1, the computed values for ion generatio...

Noble Gas Plasma Produced by Fission Fragments

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=4896&context=rtd

Theoretical and experimental investigation of the auxiliary discharge type converter

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=5125&context=rtd

Investigation of an auxiliary discharge thermionic converter using barium oxide electrodes

The ionization of pure, mixed and cesium-seeded noble gas systems by fission fragments has been investigated using ceramic-metal tubes operated in a high neutron flux region of a nuclear reactor. An analysis of the production and transport of ions and electrons in the tube has shown that when the charge loss in the plasma is predominantly by volume recombina¬ tion of molecular ions and electrons, the tube current is proportional to (voltage) / . Experimental current-voltage data in neon, argon, xenon and a neon-argon mixture with Ar/Ne of 10"3 for gas pressures of 240 and 4-00 torr and a neutron flux 10 3 cm ^ sec ^ exhibited the dependence of current on (voltage)' . Calculation of the magnitude of the current com¬ pletely from theory, using a detailed model of ion generation rate, showed an agreement with the experimental data within +10%. For a gas pressure of 24-0 torr, where the ion generation rate was of order 5 x 10lf^ cm"3 sec’1 the average ion density computed for the pure gases was2.5 x 1011 cm" ’ but for the Ne-Ar mixture (where the loss rate of argon ions is reduced) the ion density was about four times higher, i,e. —<1.0 x 1012 cm’3. Some preliminary studies of reaction kinetics in Ne-Ar mixtures, designed to maximize ion number density, have indicated that with the known ion genera¬ tion rates^at a^neutron flux of 1013 cm'2 sec'1, densities as high as ^ 4 x 10 cm 3 may be obtained for a mixture with Ar/Ne of lO"^ at values of p 100 torr . Lack of detailed knowledge of some of the relevant con¬ version processes in an argon-cesium mixture inhibits at present a similar study of reaction kinetics in this system. However, preliminary currentvoltage data for Ar/Cs of 10 ^ at an argon pressure of 240 torr, appears to follow a current-(voltage)1^2 relationship and indicates that the ion gen¬ eration rate is significantly higher than that for Ne-Ar or the pure gases under the same conditions .

INVESTIGATIONS ON THE DIRECT CONVERSION OF NUCLEAR FISSION ENERGY TO ELECTRICAL ENERGY IN A PLASMA DIODE. Report No. 5. Annual Report, November 1, 1963-October 31, 1964

R. Silver

Papers

Nuclear generated plasmas in noble gas thermionic converters