Isotopically Selective Multiphoton Dissociation of UF<SUB>6</SUB> in Static Gas Cell at -35°C
スポンサーリンク
概要
- 論文の詳細を見る
In molecular laser isotope separation of uranium (MLIS), the compound UF<SUB>6</SUB> is a natural choice since it is the most familiar material in conventional uranium enrichment processes. The UF<SUB>6</SUB> has the sufficient chemical stability and the highest vapor pressure of all known uranium compounds. However, the studies on MLIS have not been as successful as those on AVLIS (atomic vapor laser isotope separation) until recently owing to the lack of the suitable infrared lasers that can be tuned precisely to the absorption center of the <SUP>235</SUP>UF<SUB>6</SUB>ν<SUB>3</SUB> band near 16 pm.<BR>Many attempts have been made to develop the 16 μm lasers. Continuously tunable 16 μm radiation was obtained using an optical parametric oscillator<SUP>(1)(2)</SUP>. Since the available energy was very small, however, the second laser for dissociation of the vibrationally excited UF<SUB>6</SUB> was needed. The groups at Los Alamos National Laboratory and Centre d'Etudes Nucleaires at Saclay both utilized the UV laser for this purpose. But it was found<SUP>(3)(4)</SUP> that the use of the UV laser deteriorates the isotopic selectivity because even unexcited UF<SUB>6</SUB> absorbs the UV laser very strongly. Although infrared multiphoton excitation without using UV lasers was expected to yield better selectivity, no high-power gas laser had the capability of tuning the laser frequency to the center of the <SUP>235</SUP>UF<SUB>6</SUB> 16 μm band until the advent of the p-H<SUB>2</SUB> Raman laser. For example, the CO<SUB>2</SUB>-pumped CF<SUB>4</SUB> laser was found to be successful in dissociating UF<SUB>6</SUB> only in the region between 610 and 620 cm<SUP>-1(5)</SUP>, which corresponds to the lower frequency tail of the absorption of <SUP>238</SUP>UF<SUB>6</SUB>.<BR>Immediately after the proposal<SUP>(6)</SUP> and the following successful demonstration<SUP>(7)</SUP>, it was recognized that p-H<SUB>2</SUB> Raman laser is the most suitable 16 μm laser which is capable to tune over the region of <SUP>235</SUP>UF<SUB>6</SUB> absorption. It is a scalable gas laser based on well established CO<SUB>2</SUB> laser technology and on the very efficient stimulated rotational Raman scattering conversion in a gaseous medium.<BR>Using this p-H<SUB>2</SUB> Raman laser, Rabinowitz et al.<SUP>(8)</SUP> demonstrated infrared two-color multiphoton excitation to dissociate UF<SUB>6</SUB> selectively at ambient temperature. Although their choice of all-infrared excitation scheme itself is more advantageous than IR-UV excitation scheme, the selectivity was not very high probably owing to the fact that UF<SUB>6</SUB> was not cooled with an expansion nozzle. They reported a selectivity of 1.20. Since the amount of UF<SUB>6</SUB> treated in their experiment was small, they developed a complicated on-line detection system for the isotopic selectivity measurement.<BR>It is always of great interest from a practical viewpoint whether the selectivity observed at the time immediately after dissociation is deteriorated by the secondary reactions or not. In this note, an attempt was made to irradiate UF<SUB>6</SUB> contained in a static gas cell with one-frequency p-H<SUB>2</SUB> Raman laser and to obtain the selectivity based on the stable compound remaining in the cell after irradiation.
- 一般社団法人 日本原子力学会の論文
著者
-
Namba Susumu
Institute Of Physical And Chemical Research
-
Tashiro Hideo
Institute Of Physical And Chemical Research
-
TAKEUCHI Kazuo
Institute of Physical and CHemical Research (RIKEN)
-
MIDORIKAWA Katsumi
Institute of Physical and Chemical Research
-
ISOMURA Shohei
Institute of Physical and Chemical Research
-
OYAMA Toshiyuki
Institute of Physical and Chemical Research
-
SATOOKA Sakae
Institute of Physical and Chemical Research
-
TAKEUCHI Kazuo
Institute of Physical and Chemical Research
関連論文
- Laser-Acoustic Microscope : Ultrasonic Imaging and Microscopy
- Photoacoustic Subsurface Imaging by Laser Beam Irradiation : Ultrasonic Imaging
- Measurement of the Temporal Change in the Refractive Index of ZnS Thin Films
- Amplitude Modulation of 6328 Å Guided Wave in ZnS-Glass Directional Coupler by Free-Carrier Injection
- Relativistic Change in Bond overlap population for the Study of Relativistic Effects on Bond Length of Diatomic Molecules
- Ablation of Fused Quartz by Ultraviolet, Visible or Infrared Laser Coupled with VUV Laser
- Low Temperature Magnetoresistance of a Quasi-Ballistic Narrow Wire Confined by Split Metal Gates
- Dynamic Behavior of 30-ps Pulsed-Laser Annealing in Ion-Implanted Si
- Thermal Shift of Laser Wavelength in CdS during Excitation Pulse of Electron Beam
- Dependences of Laser Wavelength and Pumping Power at Threshold on Cavity Length in Electron-Beam-Pumped CdS Laser
- Low-Temperature Silicon Epitaxial Growth by CO_2 Laser CVD Using SiH_4 Gas
- Tritium isotope separation by multiphoton dissociation of CF3CTClF.
- Efficient energy utilization in laser-assisted isotope separation of tritium.
- Isotopically Selective Multiphoton Dissociation of UF6 in Static Gas Cell at -35°C