Isotope separating element

The three isotopes of hydrogen are almost indistinguishable for most chemical purposes, but a mass Spectrometer can see them as three different entities of mass 1, 2, and 3 Da. Isotopes of other elements can also be distinguished. Mass spectrometry is important for its ability to separate the isotopes of elements. 

Different combinations of stable xenon isotopes have been sealed into each of the fuel elements in fission reactors as tags so that should one of the elements later develop a leak, it could be identified by analyzing the xenon isotope pattern in the reactor s cover gas (4). Historically, the sensitive helium mass spectrometer devices for leak detection were developed as a cmcial part of building the gas-diffusion plant for uranium isotope separation at Oak Ridge, Tennessee (129), and heHum leak detection equipment is stiU an essential tool ia auclear technology (see Diffusion separation methods). 

Laser isotope separation techniques have been demonstrated for many elements, including hydrogen, boron, carbon, nitrogen, oxygen, sHicon, sulfur, chlorine, titanium, selenium, bromine, molybdenum, barium, osmium, mercury, and some of the rare-earth elements. The most significant separation involves uranium, separating uranium-235 [15117-96-1], from uranium-238 [7440-61-1], (see Uranium and uranium compounds). The... 

Enrichment, Isotopic—An isotopic separation process by which the relative abundances of the isotopes of a given element are altered, thus producing a form of the element that has been enriched in one or more isotopes and depleted in others. In uranium enrichment, the percentage of uranium-235 in natural uranium can be increased from 0.7% to >90% in a gaseous diffusion process based on the different thermal velocities of the constituents of natural uranium (234U, 235U, 238U) in the molecular form UF6. 

MS is based on the production of gas phase ions and on their separation according to their mass-to-charge (m/z) ratios. It was introduced at the end of the nineteenth century and for a long time it was confined to the physical sciences, being used to study elementary particles of matter. Pioneering works by J. J. Thomson, F. W. Aston and A. J. Dempster provided the basis for the determination of the isotopes of elements. In the 1940s, MS... 

Using mass spectrometry, it is possible to determine the molecular weight of the compound being analyzed. It is also possible to distinguish between isotopes of elements. Thus, 14N and 15N can be separated and quantified using mass spectrometry. 

In 1994 and 1995 Dr. Darleane Hoffinan of LLNL in Cahfornia and others from Germany used the Separator for Heavy Ion Reaction Products (SHIP) at the GSI laboratory in Darmstadt, Germany, to produce two new isotopes of element 110. 

The XPS valence band spectra for the dioxides of the transuranium elements (from Np to Bk) have been presented in an extensive and pioneering work that also includes core level spectra and has been for a long time the only photoemission study on highly radioactive compounds. High resolution XPS spectra (AE = 0.55 eV) were recorded on oxidized thin metal films (30 A) deposited on platinum substrates with an isotope separator. (The oxide films for Pu and the heavier actinides may contain some oxides with lower stoichiometry, since starting with Pu, the sesquioxides of the heavier actinides begin to form in high vacuum conditions.)... 

The Dubna researchers tried unsuccessfully for many months to repeat their apparent synthesis of element 114. Eventually, however, their persistence was rewarded with the sighting of a different isotope of element 114, with 174 neutrons and a lifetime of a few seconds. This time the researchers saw two separate decay events, making the sighting much more secure. Encouraged by this success, they changed the target material to califomium-248 and manufactured element 116, which decayed by alpha emission to element 114. 

The bombardment took place in the Berkeley 60-in. cyclotron, after which the target material was shipped to the Metallurgical Laboratory at Chicago for chemical separation and identification. A crucial step in the identification of the a-emitting nuclide as an isotope of element 96, 2 Cm, was the identification of the known 224sPu as the a-decay daughter of the new nuclide. 

The alkoxides of actinides are rarely studied except the derivatives of uranium and thorium, as interest in the alkoxides of these 2 elements has increased by the hope to use them in the isotope-separation processes. The study of uranium alkoxides was initiated by groups led by Gilman and Bradley in the 1950s. The major part of this work is still carried out at the Nuclear Research Center at Los Alamos in the United States by the group of Sattelberger et al. [1671]. The detailed data on alkoxides ofuranium is provided in a number of... 

The correlation agreement obtained here renders further support to the proposed Covalon conduction theory and leads to a further prediction that for a given element with N > 1, the Tc for that element will become higher if the number N is reduced to N = 1 (isotopically pure) through an isotope separation process. Conversely, if Nb and La with N = 1 are doped with relatively long half-life isotopes, their Tc should go down. These experiments have not been carried out yet by anyone as of this writing. 

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. 

Like most other on-line isotope separators (ISOLs), the Chalk River device was previously operated with its ion source essentially in line with the primary accelerator beam so that nuclei produced by reactions in a target would recoil directly into the ISOL ion source. We used a FEBIAD ion source [KIR/6], which was characterized by long cathode lifetime and good efficiency for a wide variety of elements. 

At the separator VASSILISSA attempts were undertaken to search for new isotopes of element 112 by irradiation of 238U with 48Ca ions [45]. The irradiation started in March, 1998. Two fission events were measured resulting in a cross section of 5.0 pb. The two events were tentatively assigned to the residue 283112 after 3n evaporation. 

Three isotopes of hydrogen are known H, 2H (deuterium or D), and 3H (tritium or T). Although isotope effects are greatest for hydrogen, justifying the use of distinctive names for the two heavier isotopes, the chemical properties of H, D, and T are essentially identical except in matters such as rates and equilibrium constants of reactions in addition, diverse methods of isotope separation are known. The normal form of the element is the diatomic molecule the various possibilities are H2, D2, T2, HD, HT, and DT.1 Naturally occurring hydrogen contains 0.0156% deuterium, whereas tritium occurs naturally in amounts of the order of 1 in 1017. 

The leading process of this type is the Australian SILEX system (which is also being used to carry out isotopic separation for other elements such as silicon and zirconium). 

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