Elemental analyses, spectral nuclear measurement

Although ICP-MS has been used for analysis of nuclear materials, often the entire instrument must be in an enclosed hot enclosure [350]. Sample preparation equipment, inlets to sample introduction systems, vacuum pump exhaust, and instrument ventilation must be properly isolated. Many of the materials used in the nuclear industry must be of very high purity, so the low detection limits provided by ICP-MS are essential. The fission products and actinide elements have been measured by using isotope dilution ICP-MS [351]. Because isotope ratios are not predictable, isobaric and molecular oxide ion spectral overlaps cannot be corrected mathematically, so chemical separation is required. 

Instrumental analysis is possible if spectral inter ference can be avoided by a proper choice of the incident energy or the measuring conditions (see Interferences). If not, the radionuclide B, formed from the analyte element A, has to be separated radiochemically from interfering radionuclide(s) D, formed out of interfering element(s) C. The latter case is called radiochemical analysis, in contrast to instrumental analysis for the former. This section deals with some major differences between radiochemical separation and common chemical separation, used for non-nuclear methods of analysis. 

The narrow spectral line of a DL enables isotope selective analysis. For light and heavy elements (such as Li and U) the isotope shifts in spectral lines are often larger than the Doppler widths of the lines, in this case isotopically selective measurements are possible using simple Doppler-limited spectroseopy - DLAAS or laser induced fluorescence (LIF). For example, and ratios have been measured by Doppler-limited optogalvanic. spectroscopy in a hollow cathode discharge. DLAAS and LIF techniques have been combined with laser ablation for the selective detection of uranium isotopes in solid samples. This approach can be fruitful for development of a compact analytical instrument for rapid monitoring of nuclear wastes. 

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