Isotope separation by high power pulsed laser through multiphoton dissociation

The field of this research has been the separation of 34S through multiphoton dissociation of SF6 molecules with irradiating focused pulses of a high-power CO2 pulsed laser in laboratory scale. To achieve the above goal, first the efforts were done to do a theoretical survey on electronic, rotational and vibrational energy states of atoms and molecules, along with a review on the isotopic effects of atoms on them. It provided a clear viewpoint about condition and structure of these states in atomic and molecular isotopic species. Secondly, on basis of the above knowledge, and so description of the two isotope selective process of atomic stepwise ionizationand molecular multiphoton dissociation, an exact and detailed study of the two laser isotope separation methods: AVLISand MOLIS, determining the abilities and disabilities of each one, particularly about the Uranium and Sulfur isotopes, was done. In addition to that, in comparison to the conventional non-laser methods, the other laser methods were reviewed to specify each one's advantages and disadvantages in compare to the other one. In experimental phase, after designing and manufacturing a suitable high-vacuum irradiation cell and related gas mixing and irradiation array, the phenomenon of selective multiphoton dissociation of 32SF6 molecules in a mixture of SF6 : H2 with ratio of 1:10 and in three initial pressures of 0.5, 0.1 and 0.05 (mbar) of SF6 were successfully experimented and more than 102 separation factor were achieved. As it was expected, exponential behavior of he separation factor and abundance of the isotopic species in terms of the number of incident pulses, and reduction of the separation factor and dissociation selectivity with the increase of the mixture pressure were clearly observed. Finally, it was indicated that the yield of the process, from the point of the achieved 34S mass versus the number of pulses, significantly increased with decreased of the mixture initial pressure