Use of Very-Short-Lived Isotopes in Activation Analysis

Anders, O.U.

doi:10.1021/ac60180a025

Cited by 35 publications

(12 citation statements)

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“…With a measured value of sample thickness, it is now possible to test the validity of simplification of equation ( 2). The bremsstrahlung shape, for electrons of 35 MeV energy and a tungsten target was generated from the Schiff equation [6]. The cross section of the 25 Mg(y,p) 24 Na and 204 Pb(y,n) 203 Pb reactions were taken from the CHARGED PARTICLES AND PHOTONS Relationship between logarithm of specific activity and 2pp.…”

Section: Resultsmentioning

confidence: 99%

“…This technique also avoids neutron induced activity as the (y,n) reaction does not occur. The dominant feature in the interaction of photons with a nucleus is the giant resonance in the absorption process [35]. This phenomenon occurs with all nuclei and is a fundamental property of the nucleus.…”

Section: B Reaction Thresholdsmentioning

confidence: 99%

“…The maximum energy of the photon beam is 35 MeV. The average intensity before conversion of the electrons is 50 fjiA.…”

Section: Determination Of Oxygen By Gamma Photon Activationmentioning

confidence: 99%

“…The second reaction which could be the more disturbing is negligible because of the chemical nature of the element. For the first one, if one considers results obtained for the competitive reactions producing carbon-1 1 and nitrogen-13 at 35 MeV, it should be possible to neglect it for high purity metals.…”

Section: Determination Of Oxygen By Gamma Photon Activationmentioning

confidence: 99%

“…It appears that in photon activation analysis, it is necessary to limit the maximum energy to about to 30 to 35 MeV because some interfering reactions exist at higher energies. For example, nitrogen and oxygen can cause uncertainty in the carbon determination and oxygen interferes with the nitrogen determination.…”

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Modern trends in activations analysis vol. 2

DeVoe¹,

LaFleur²

1969

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Section: Resultsmentioning

confidence: 99%

Section: B Reaction Thresholdsmentioning

confidence: 99%

“…The maximum energy of the photon beam is 35 MeV. The average intensity before conversion of the electrons is 50 fjiA.…”

Section: Determination Of Oxygen By Gamma Photon Activationmentioning

confidence: 99%

Section: Determination Of Oxygen By Gamma Photon Activationmentioning

confidence: 99%

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confidence: 99%

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Modern trends in activations analysis vol. 2

DeVoe¹,

LaFleur²

1969

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Cyclic Activation Analysis

Hou¹

2000

Encyclopedia of Analytical Chemistry

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Cyclic activation analysis (CAA) is a method of activation analysis for elemental analysis in which a sample is irradiated, decayed, counted, then irradiated again, and this process is repeated for a number of cycles, the spectra from each counting being summed to give a final total spectrum. By this process, the counts of a short‐lived nuclide of interest are considerably increased and the analytical sensitivity of elements is significantly improved. The most commonly used CAA method is cyclic neutron activation analysis (CNAA) by irradiation with thermal, epithermal, and fast neutrons produced from a nuclear reactor, accelerator, or isotopic neutron source. A nuclear reactor can supply a very high neutron flux and is most often used for this purpose. At least 20 elements which produce short‐lived nuclides (half‐life less than 100 s) by thermal neutron bombardment, and also more than 10 elements which produce nuclides with half‐lives of 100–600 s can be determined by thermal and epithermal neutron CAA. This technique has been widely applied in biological, environmental, geological, and industrial studies, and the most often measured elements include Se, F, Pb, Hf, Sc, O, Ag, and Rh. The advantages of CAA, as compared with conventional activation analysis, include significant improvements of the detection limits, analytical precision, and accuracy for the elements by using short‐lived nuclides, short experimental time, increased number of samples per unit time, a capability for the estimation or confirmation of the half‐lives of short‐lived nuclides and determination of the degree of homogeneity of samples. However, the application of CAA is limited by the number of elements determined, because only some of the elements determined by conventional activation analysis can be determined by this method. In addition, dead time and pile‐up are serious problems in CAA and must be corrected. The principle, selection of optimum experimental conditions, detection limit, and analytical precision of CAA, and also the dead time and pile‐up corrections, are discussed in this article.

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Cyclic Activation Analysis

Hou

2008

Encyclopedia of Analytical Chemistry

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Cyclic activation analysis (CAA) is a method of activation analysis for elemental analysis, in which a sample is irradiated, decayed, counted, and then irradiated again. This process is repeated for a number of cycles, and the spectra from each counting are summed together to give one final total spectrum. By this process, the counts of a short‐lived nuclide of interest are considerably increased, and the analytical sensitivity of elements is significantly improved. The most commonly used CAA is the cyclic neutron activation analysis (CNAA) by irradiation with the thermal, epithermal, and fast neutrons produced from nuclear reactor, accelerator, and isotopic neutron source. The nuclear reactor can supply a much high neutron flux and is most often used for this purpose. At least 20 elements produced short‐lived nuclides (half‐life <100 s) by thermal neutron bombardment, and more than 10 elements produced nuclides with half‐life of 100–600 s. These can be determined by thermal and epithermal neutron CAA. This technique has been widely applied in biological, environmental, geological, and industrial studies, and most often measured elements include Se, F, Pb, Hf, Sc, O, Ag, and Rh. The advantages of CAA, as compared with conventional activation analysis, include significant improvement in the detection limit, analytical precision, and accuracy for the elements by using short‐lived nuclides; short experimental time and increased analytical number of samples per unit time; capability of estimation or confirmation of the half‐life of the short‐lived nuclide; and determination of the degree of homogeneity of a sample. However, the application of CAA is limited by the number of elements determined, because only some of the elements determined by conventional activation analysis can be determined by this method. In addition, dead time and pileup are serious problems in CAA and must be corrected. The principle, selection of optimal experiment conditions, detection limit, analytical precision of CAA, as well as the dead time and pileup corrections are discussed in this article. Some applications of this method are highlighted.

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Use of Very-Short-Lived Isotopes in Activation Analysis

Abstract: Basis of the Analysis of the Paragenesis of Minerals" (Translation, Consultants Bureau, New York), 1959. (6) Roozeboom, H. W., Z. physik. Chem. 15, 147(1894). (7) Stokes, C. G., Proc. Roy. Soc. (London) 49A, 171 (1891).

Cited by 35 publications

References 2 publications

Modern trends in activations analysis vol. 2

Modern trends in activations analysis vol. 2

Cyclic Activation Analysis

Cyclic Activation Analysis

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