Fission fragments and energy spectra of primary electrons in a fissioning plasma

Abstract

Some isotopes like 3He, 23BUF6 gases irradiated by thermal neutron flux may produce partially ionized plasma with the presence of fast particles like protons, tritium or heavy fission fragments. If a sample with 3He gas sets in thermal neutron flux, the helium atoms may born highly energetic particles: protons and tritium nuclei, which create in their own turn primary electrons and their other successive generations.In the present paper Boltzmann kinetic equation for plasma, created by volume source of ionization is developed and solved for special cases, like presence of external electric field, strong enough to cause Townsend ionization. The ways of possible existing of highly energetic electrons accelerated by strong electric field energy also thoroughly discussed. Statistical approach based on the Monte Carlo technique including definition of self-consistent electric field formed by boundary conditions and nuclear induced plasma internal properties coupled with direct Boltzmann formalism also was developed and discussed. Thus the outbreak or the time explosion of the energy distributions of all fast particle including primary and secondary electrons are calculated in the programming complex as a function of time from 10 ps to 10 ns and for different neutron flux pulses and neutrons homogeneous spatial distribution. Non-linear problems such as an electron–ion recombination and successive generation of secondary electrons and electron queues are solved by Monte Carlo technique and comprehensively described. Detailed calculations show that so called runaway electrons are not appearing in nuclear induced plasma and whatever strong external electric field applied, there is no way to supply them relativistic energy and create so called runaway electrons. The appearance of electrons with an energy around MeV is possible when electrons (beta electrons) are born within nucleus due to internuclear transformations of up and down quarks affected by neutrinos oscillations. It takes place in nuclear fission process provoked by neutrinos and antineutrinos Reines et al (1960 Phys. Rev. 117 159). Time dependent spectra of primary electrons as well as their successive generations are calculated and compared with existing experimental data and developed for nuclear induced Boltzmann kinetic equation solutions. It is also should be noted that the bremsstrahlung radiation or braking radiation can not be treated as a type of force (friction force). It is clear that the transformation of kinetic energy into electromagnetic energy is a unique phenomenon and if it exists while fast electron is stopping in the medium, then there should be the reversed process, when electron gains its kinetic energy from surrounding electric field.