Isotope separation scheme

Although the formidable difficulties associated with isotope separation schemes based on photochemical vibrational excitation plus chemical reaction continue to attract considerable attention, some earlier hopes appear to have been dashed. An experiment performed in 1970 by Mayer et al. has been much quoted. They reported irradiating mixtures of CHjOH and CD3OD in the presence of Bts with lines from an HF laser that are absorbed only by CH3OH. Product analysis indicated the selective depletion of the CH3OH. This observation was interpreted in terms of a selective reaction between vibrationally excited CH3OM and Bra, nnd it appeared to point the way to an economic method for the production of heavy water. However, the results of a careful re-examination of this system have just... 

The essential requirements for any photochemical isotope separation scheme follow ... 

The essential ingredients for a scheme of isotope separation by lasers are 154e)... 

Prior to about 1955 much of the nuclear information was obtained from application of atomic physics. The nuclear spin, nuclear magnetic and electric moments and changes in mean-squared charge radii are derived from measurement of the atomic hyperfine structure (hfs) and Isotope Shift (IS) and are obtained in a nuclear model independent way. With the development of the tunable dye laser and its use with the online isotope separator this field has been rejuvenated. The scheme of collinear laser/fast-beam spectroscopy [KAU76] promised to be useful for a wide variety of elements, thus UNISOR began in 1980 to develop this type of facility. The present paper describes some of the first results from the UNISOR laser facility. 

In alkaline solutions, the mechanism is apparently the same as that found in acid solutions at high values of the overpotential, namely the first charge-transfer step is at quasi-equilibrium, with the ion-atom recombination step following as the rate-determining step at high surface coverage. This scheme is also confirmed by the high value of the isotope separation factor observed in this system. 

A second Welsh chemical warfare establishment was at Rhy-dymwyn, near Mold in Clwyd. Here, the Ministry of Supply built a gas factory which was joined, in 1942., by an even more secret installation an isotope-separation plant, part of the British project to create an atom bomb. The atomic plant employed over one hundred people, supervised by twenty Oxford scientists from the Clarendon Laboratory. Employees from one site were not allowed into the other, but as workers at both had to carry gas masks it was assumed by the local inhabitants that they were all engaged on the same project this, it was rumoured, was a scheme to manufacture synthetic rubber. 

Other schemes for isotope separation or enrichment based on photodtemical excitation with i.r. lasers, but not involWog chamical reaction, have also been successful. As these fall outside the mainstream of this chapter thty will be described only briefly. 

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