Two-photon laser isotope separation of atomic uranium-spectroscopic studies, excited state lifetimes, and photoionization cross sections

Technical Report · Thu May 01 04:00:00 EDT 1975

OSTI ID:4129156

Janes, G S; Itzkan, I; Pike, C T; Levy, R H; Levin, L

Experimental studies are described wherein an atomic beam of uranium vapor produced by electron beam evaporation is selectively excited and ionized by light from two short-pulse, narrow bandwidth, tuned dye lasers, and detected and analyzed by a mass spectrometer. The total number of ions per pulse produced is small; however, the time of production is known precisely. By counting single ions, using digital logic and multiplexing the mass spectrometer between $sup 238$U and $sup 235$U, it is possible to measure isotope ratios as a function of exciter wavelength, and to correct for background effects and spurious ions. These results demonstrated 50 percent enrichment of $sup 235$U/$sup 238$U. Excited state lifetimes were measured by observing yields as a function of the delay between the two laser pulses. In addition, for an excitation wavelength of 4266.325 A the variation of two-step photoionization efficiency was measured as a function of the wavelength of the ionizing laser. The maximum yield at an ionizing wavelength of 3609 A corresponds to a cross section of 2 x 10$sup -17$ cm$sup 2$ for matched linewidths. Also, the ionization potential of uranium was determined to be 6.187 +- .002 eV. (auth)

• Research Organization: Avco-Everett Research Lab., Everett, Mass. (USA)
• NSA Number: NSA-33-009408
• OSTI ID: 4129156
• Report Number(s): NP--20736
• Country of Publication: United States
• Language: English

Related Subjects

*URANIUM 235-- LASER ISOTOPE SEPARATION
*URANIUM 238-- LASER ISOTOPE SEPARATION
050503* --Nuclear Fuels--Enrichment--Laser Excitation
DYE LASERS
IONIZATION POTENTIAL
N47120* --Isotope & Radiation Source Technology--Isotope Separation (Industrial)--Uranium