Atomic Laser Isotope Separation Research Articles

Uranium Isotopes Separation Technique

This work describes the atomic laser isotope separation (LIS). The (LIS) plant means calculating the values of a large number of parameters in order to optimize some objective function. Here we use simple model to describe the elementary physical processes: evaporation, vapor expansion, interaction between photons and atoms, ion extraction etc...concentrated on theoretical and empirical bases. An optimization process for the separation of Uranium isotopes is described and discussed.

Uranium Isotopes Separation Technique

This work describes the atomic laser isotope separation (LIS). The (LIS) plant means calculating the values of a large number of parameters in order to optimize some objective function. Here we use simple model to describe the elementary physical processes: evaporation, vapor expansion, interaction between photons and atoms, ion extraction etc...concentrated on theoretical and empirical bases. An optimization process for the separation of Uranium isotopes is described and discussed.

Molecular laser isotope separation versus atomic vapor laser isotope separation

In this work, the competitive molecular and atomic laser isotope separation methods are investigated to evaluate the potential of each une for more economical fuel fabrication of enriched uranium celas which can be practically used in light water reactors (LWR). The advantages, drawbacks and feasibility of various techniques of laser isotope separation including AVLIS and the main MLIS methods such as MOLIS, CRISLA, and SILARC techniques have been reviewed. Laser isotope separation (LIS) deserves an intensive research, because laser techniques have a number of advantages over traditional ones, such as highly selective elementary separation event, possibility of separating the required isotope, low energy consumption, short start up time and practically single-stage production, which may economize fuel processing [11.

Spatial Effects of Laser Beam Propagation and Photoionization in a Multilevel Photoionization System

Spatial near-resonant effects on laser beam propagation in an atomic laser isotope separation system have been studied by 2D simulation. It was found that the initial amplitude of nonuniformity grows up during the propagation, which degrades the photoionization rate of the target atom. The spatial effects become large for the longer incident laser pulse.

Reduction of Charge Transfer Loss in Atomic Laser Isotope Separation by Production of Excited Ions through Autoionization Levels

A new technique to reduce charge transfer loss when extracting ions from photoionized plasma has been developed, thereby increasing the efficiency of atomic vapor laser isotope separation (AVLIS). By selecting autoionization levels, specific isotopes are ionized to the excitation levels of the ions. Cross sections for charge transfer between specific excited ions and ground state atoms are smaller than those between ground state ions and ground state atoms. The effectiveness of this technique was confirmed by measuring the difference in charge transfer cross sections between Gd++Gd and Gd+*+Gd. When the gadolinium atoms were ionized at the 53,616cm-' autoionization level, the kinetic energy of the released electrons was measured with a time of flight electron spectrometer (energy resolution>30meV) and the produced ions were determined to be at levels of 4f 75d6s'0D13/2 and 8D,/2. The charge transfer cross section for Gd+*(10D13/2 1,935cm-', 8D,,2 3,427 ~m-')fGd(~D~) was 1.5~10-'~m~ at an impact energy of 250eV, which was a smaller value than that for Gdf(Dsl2 O~m-')+Gd(~D~)(2.5xlO-'~ m'). When specific isotopes of gadolinium were ionized by autoionization, the charge transfer loss could be reduced from 14% to 9% at an atomic density of 1 x 10'' m-' in the typical isotope separation region. Because this effect is also expected in charge transfer between other heavy metallic ions, it should be possible to improve the ion collection efficiency for isotopes like uranium by selecting autoionization levels to produce specific excited ions.

Reduction of Charge Transfer Loss in Atomic Laser Isotope Separation by Production of Excited Ions through Autoionization Levels.

A new technique to reduce charge transfer loss when extracting ions from photoionized plasma has been developed, thereby increasing the efficiency of atomic vapor laser isotope separation (AVLIS). By selecting autoionization levels, specific isotopes are ionized to the excitation levels of the ions. Cross sections for charge transfer between specific excited ions and ground state atoms are smaller than those between ground state ions and ground state atoms. The effectiveness of this technique was confirmed by measuring the difference in charge transfer cross sections between Gd+Gd and Gd+*+Gd. When the gadolinium atoms were ionized at the 53,616cm−1 autoionization level, the kinetic energy of the released electrons was measured with a time of flight electron spectrometer (energy resolution>30meV) and the produced ions were determined to be at levels of 4ƒ 75d6s 10 D 13/2 and 8 D 7/2. The charge transfer cross section for Gd+* (10 D 13/2 1,935cm−1, 8 D 7/2 3,427 cm−1)+Gd(9DJ) was 1.5×10−18 m2 at an impact energy of 250eV, which was a smaller value than that for Gd+ (10 D 5/2 0cm−1)+Gd(9DJ)(2.5×m−18 m2). When specific isotopes of gadolinium were ionized by autoionization, the charge transfer loss could be reduced from 14% to 9% at an atomic density of 1×1019 m−3 in the typical isotope separation region. Because this effect is also expected in charge transfer between other heavy metallic ions, it should be possible to improve the ion collection efficiency for isotopes like uranium by selecting autoionization levels to produce specific excited ions.

Analysis of Laser Beam Propagation Effects in Atomic Laser Isotope Separation

In the atomic laser isotope separation process, the laser beams propagate through the atomic vapor over a long distance. It has been shown that the laser-atom interactions significantly modify the laser pulse shape and propagation velocity, resulting in degradation of the isotope separation efficiency. These propagation effects have been analyzed quantitatively, and a simple scaling formula has been derived to estimate the necessary laser energy for such optically thick atomic vapor. The optimum conditions of incident laser pulse have also been discussed.

Numerical study of propagation of laser pulses in a multilevel photoionization system

Propagation of laser pulses in a multilevel photoionization system is studied for atomic laser isotope separation. For this purpose a simulation code called cealis-p has been developed. Through numerical solutions of coupled Maxwell–Bloch equations we illustrate the propagation characteristics and the influence on the photoionization efficiency. It is shown that near-resonant interactions with the nontarget isotope will significantly alter the laser-pulse shape, carrier frequency, and propagation velocity, resulting in degradation of the photon-utilization efficiency and ionization efficiency.