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  • 82.40  (6)
  • 33.00  (4)
  • 1
    Electronic Resource
    Electronic Resource
    CO2 laser isotope separation of tritium with (CF3)3CT (1987)
    Springer
    Applied physics 42 (1987), S. 167-172 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60.Kg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new working molecule 1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)-propane-2-t (CF3)3CT, is reported for the isotope separation of tritium by TEA CO2-laser-induced multiphoton dissociation (MPD). Selective and efficient dissociation of (CF3)3CT was observed by irradiation at about 980 cm−1 where (CF3)3CH was nearly transparent. The critical fluence for dissociation of (CF3)3CT at 10R(28) 980.9 cm−1 was estimated to be as low as 4.6 J/cm2, which is the lowest of the tritiated halocarbons that we have ever reported. A detailed study was made of the pressure dependence of the dissociation rate constants for (CF3)3CT and (CF3)3CH to clarify the collisional effects in their MPD. The hydrogen isotope exchange between (CF3)3CH and HTO was found to be extremely rapid, which is advantageous in the practical laser separation cycle for tritium removal from water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00693880
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  • 2
    Electronic Resource
    Electronic Resource
    Cross section of supercooled238UF6 in multiphoton absorption induced by 16 micrometer Raman-laser radiation (1994)
    Springer
    Applied physics 59 (1994), S. 475-477 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 33.00
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Measurements of multiphoton absorption of 16 µm Raman-laser radiation in supercooled238UF6 at 90 K were performed by using a pulsed Laval nozzle with an optical path length of 50 cm. The laser fluence was varied between 50 and 500 mJ/cm2 for four frequencies in the range from 625 to 629 cm−1. The energy absorbed by238UF6 molecules was investigated as a function of laser frequency or fluence, and highly accurate results were obtained with the use of the nozzle whose optical path length is much greater than that of nozzles used before. The results indicated that the absorption cross section at the peak absorption frequency (627.8cm−1) was proportional to the −1/3 power of the fluence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081071
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  • 3
    Electronic Resource
    Electronic Resource
    Measurements of235U/238U isotopic ratio in the photoproduct UF5 by multiphoton ionization and time-of-flight mass spectrometry (1996)
    Springer
    Applied physics 62 (1996), S. 515-519 
    Details
    ISSN: 1432-0649
    Keywords: 07.75 ; 33.00 ; 82.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A MultiPhoton-Ionization Time-Of-Flight Mass Spectrometry (MPI/TOFMS) apparatus was developed for real-time measurement of the uranium isotopic ratio in nascent UF5 formed by the 266 nm photolysis of effusive UF6 ( 〈 300 K, ≈ 1.3 × 10−4 Pa). The UF5 was selectively and efficiently multiphoton ionized by 532 nm radiation at appreciably low fluences ( 〈 10 J/cm2). The main ions observed, U+ and U2+, were subsequently analyzed with a TOFMS with mass resolution of 1190 to separate235U n+ and238U n+ completely. The isotopic ratio measurements showed good precision resulting from the excellent agreement which was observed between the isotopic ratios in UF5 products and those in a parent UF6 sample. These results suggested that the MPI/TOFMS method can be applied to the real-time analysis of separation factors in the molecular laser isotope separation of uranium by ionization of UF5 following the infrared photodissociation of UF6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081053
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  • 4
    Electronic Resource
    Electronic Resource
    Vibrational predissociation of UF6 clusters in supersonic Laval nozzle flow (1996)
    Springer
    Applied physics 63 (1996), S. 57-61 
    Details
    ISSN: 1432-0649
    Keywords: 33.00 ; 82.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The time-dependent change in the concentration of UF6 monomers populated in the ground state was monitored in a supersonic Laval nozzle flow with an infrared diode-laser spectrometer in which the frequency of the laser beam was fixed at theυ = 1 ← 0 transition (627.7 cm−1) of theν 3 vibrational mode of the238UF6 monomer. The concentration of UF6 monomers in the ground state increased immediately after a single shot from a Raman laser tuned to a vibrational mode of UF6 clusters (614.8 cm−1) was applied to the gas in the nozzle. Subsequently, this concentration leveled off and slowly returned to the previous level. These results indicate that the population of UF6 monomers in the ground state increased as a result of the predissociation of UF6 clusters vibrationally excited with Raman laser radiation. It is demonstrated that one can utilize this procedure for vibrational predissociation of UF6 clusters as a technique to increase the concentration of UF6 monomers in an irradiation zone for molecular laser isotope separation of uranium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01112839
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  • 5
    Electronic Resource
    Electronic Resource
    Tritium isotope separation by CO2-laser irradiation at low temperatures (1984)
    Springer
    Applied physics 33 (1984), S. 83-90 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Tritium isotope separation by CO2-laser induced multiphoton dissociation of CTF3 is investigated. For the optimization of the performance of this working substance, trifluoromethane, the conditions to yield high-selectivity at high-operating pressure and low-critical fluence for complete dissociation are studied using our deconvolution procedure. The irradiation conditions are varied over the following ranges; wavenumber: 1052–1087 cm−1, gas temperature: 25°C to −78°C, CHF3 pressure: 5–205 Torr. The selectivities exceeding 104 are observed for 85–205 Torr CHF3 at −78°C by the irradiation at 1057 cm−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688351
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  • 6
    Electronic Resource
    Electronic Resource
    Laser isotope separation of tritium from deuterium: CO2-laser-induced multiphoton dissociation of C2TF5 in C2DF5 (1983)
    Springer
    Applied physics 32 (1983), S. 33-34 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Isotope separation of tritium from deuterium in heavy water was attempted by CO2-laser-induced, highly-selective multiphoton dissociation of C2TF5 present in C2DF5. Single-step T/D separation factors exceeding 3000, 1000, and 500 were attained, respectively, for the first time with CO2 laser 10P(34) 931.0 cm−1 at 10, 20, and 30 Torr pentafluoroethane pressures at −78 °C (i.e., equivalent to 15, 30, and 45 Torr at room temperature).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688772
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  • 7
    Electronic Resource
    Electronic Resource
    CO2-laser isotope separation of tritium with pentafluoroethane-T (C2TF5) (1982)
    Springer
    Applied physics 28 (1982), S. 341-348 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Isotope separation of tritium by CO2 laser-induced multiphoton dissociation (MPD) of C2TF5 is reported for the first time. The MPD spectrum obtained for C2TF5 comprised a broad peak at about 940 cm−1 where C2HF5 was nearly transparent. The unimolecular dissociation of C2TF5 was induced with much lower laser fluence than that for CTF3, another working molecule we proposed for laser isotope separation of tritium. The mechanisms and kinetics of the dissociation of C2TF5 and C2HF5 were investigated under various experimental conditions: laser frequency, pulse energy, pulse duration, tritium concentration, sample pressure, buffer gas pressure and irradiation geometry. Single-step separation factors exceeding 500 were achieved with the most efficientP(20) line in 00o–10o0 transition at 944.2 cm−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686364
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  • 8
    Electronic Resource
    Electronic Resource
    Contrast ratio and separation factor in multiphoton dissociation of supercooled UF6 irradiated with multifrequency 16 μm Raman-laser radiation (1996)
    Springer
    Applied physics 62 (1996), S. 77-81 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 33.00
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In infrared multiphoton dissociation of supercooled UF6 irradiated with multifrequency para-H2 Raman laser beams, separation factors and contrast ratios were measured by selective multiphoton ionization of the photoproduct UF5 at 532 nm followed by time-of-flight mass spectrometric analysis. The relationship between separation factor and contrast ratio is discussed theoretically and quantitatively investigated in the experiments. From this relationship, we obtain the irradiation conditions of the laser-beam fluences for attaining a high separation factor and estimate the value of the intrinsic separation factor in multifrequency dissociation of UF6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081251
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  • 9
    Electronic Resource
    Electronic Resource
    Laser isotope separation of tritium using CF3CTBrF/CF3CHBrF (1985)
    Springer
    Applied physics 37 (1985), S. 67-72 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new working molecule 2-bromo-1,1,1,2-tetrafluoroethane is reported for laser isotope separation of tritium. The multiphoton dissociation rate of CF3CTBrF is studied as a function of irradiation wavenumber, using a CO2 or NH3 laser. In a tightly focused irradiation geometry where the dissociation saturates both for CF3CTBrF and CF3CHBrF, their threshold fluences of dissociation and the geometrically biased selectivity are measured near the maximum of the dissociation rate of CF3CTBrF. When the irradiation geometry is optimized, a high selectivity exceeding 2700 is obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692551
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  • 10
    Electronic Resource
    Electronic Resource
    Growth enhancement of UF5 nano-particles assisted byα-ray ionization (1996)
    Springer
    Applied physics 62 (1996), S. 373-379 
    Details
    ISSN: 1432-0630
    Keywords: 81.40 ; 82.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract It was demonstrated experimentally for the first time that particle growth of photoproduced UFS was enhanced by ionizing radiation from an α-emitting241Am source. A gas mixture of UF6, CH4, and Ar in a reaction cell was irradiated with a single shot of a KrF laser at 248 nm to form UF5 particles. Transmission electron microscope images of the samples indicated that the average size of UF5 particles produced without the α-ray source was independent of the laser energy. UFS particles produced with the α-ray source were found to be much larger in size than those produced without the a-ray source, and the enhancement of particle growth was marked when the laser energy was low. An explanation was attempted for the anomalous behaviors of particle size distribution from the viewpoint of competition between the second-order coagulation rate and the rate of diffusion from the reaction zone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01594236
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