Shohei Isomura

Separation of Boron-10 by Low Temperature Distillation of Boron Fluoride-Methyl Fluoride Complex

A method for low temperature distillation of boron fluoride-methyl fluoride complex in a packed column was studied. The minimum volume of the column for producing highly enriched 10B was found to be smaller than required for the low temperature distillation of boron fluoride.

High enrichment of 28Si by infrared multiple photon decomposition of Si2F6

High enrichment of 28Si has been carried out using the laser isotope separation technique based on the isotopically selective infrared multiple photon decomposition of Si2F6. When about 2 Torr of Si2F6 was irradiated at a fluence of 1.0 J/cm2 per pulse with the 10P(8) line of a TEA CO2 laser at 954.55 cm-1, the compound decomposed very efficiently with high isotope selectivity. The products SiF4 and white solids were enriched with 29Si and 30Si, while the residual Si2F6 was enriched with 28Si. The atomic fraction of 28Si in residual Si2F6 increased with increasing decomposition of Si2F6; 99.9% of 28Si was obtained at a consumption of 50% of initial Si2F6. The large-scale flow experiment yielded 99.7% 28Si at a production rate of 2.5 g/h, where a mixture of 3.3 Torr Si2F6 and 6.6 Torr argon was irradiated with 10P(8) laser pulses at a repetition rate of 5 Hz. Merits and demerits of the present laser separation are discussed in comparison to those of conventional separation methods. Laser enrichment of 28Si seems promising for economical production of large quantity of pure 28Si. Various applications of silicon isotopes are briefly reviewed.

Separation of isotopes of nitrogen and oxygen by low temperature distillation of nitrogen oxide.

本報では, 一酸化窒素低温蒸留法による窒素および酸素の同位体分離を目的として, 分離過程の非定常解析法を確立し, 装置設計に必要な理論段相当高さ (HETP) などの蒸留因子の決定を試みた。その結果, 通常用いられている定常解析法による結果とも良く一致し, また実験操作時間を大幅に短縮することが可能となった。