The use of a modified Westcott-formalism in thek o-standardization of NAA: The state of affairs

Corte, F. De; Bellemans, F.; Neve, Peter De; Simonits, A.

doi:10.1007/bf02037929

Cited by 71 publications

(14 citation statements)

References 19 publications

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“…[14]) to deduce the thermal (v = 2200 m/s) neutron capture cross section, σ 0 , and the resonance integral, I 0 , from the irradiation with reactor neutrons.…”

Section: Discussionmentioning

confidence: 99%

Measurement of the thermal neutron capture cross section and the resonance integral of radioactiveHf182

et al. 2008

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The neutron capture cross sections of the radioactive isotope 182 Hf (t 1/2 = 8.9 × 10 6 yr) in the thermal and epithermal energy regions have been measured by activation at the TRIGA Mark-II reactor of the Atomic Institute of the Austrian Universities in Vienna, Austria, and subsequent γ -ray spectroscopy of 183 Hf. High values for the thermal (kT = 25 meV) cross section σ 0 = 133 ± 10 b and for the resonance integral I 0 = 5850 ± 660 b were found. Additionally, the absolute intensities of the main γ -ray transitions in the decay of 182 Hf have been considerably improved.

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“…[14]) to deduce the thermal (v = 2200 m/s) neutron capture cross section, σ 0 , and the resonance integral, I 0 , from the irradiation with reactor neutrons.…”

Section: Discussionmentioning

confidence: 99%

Measurement of the thermal neutron capture cross section and the resonance integral of radioactiveHf182

et al. 2008

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“…In the present study, the factors f and α were measured by bare triple monitor method as described in references [5,8]; MSI and g(T n ) were determined by bare dual monitor method [9]. The MSI is calculated as:…”

Section: Introductionmentioning

confidence: 99%

Development and implementation of k0-INAA standardization at 10 MW Pakistan research reactor-1

Wasim¹,

Arif²,

Zaidi³

et al. 2009

Radiochimica Acta

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Summary. The k 0 -method has been developed for 10 MW Pakistan Research Reactor (PARR-1). It involved the full energy peak efficiency calibration of HPGe detector for different counting geometries and characterization of neutron flux at three irradiation channels. Neutron flux was characterized for thermal to epithermal flux ratio, epithermal flux shape factor, modified spectral index, Westcott's g-factor and fast flux. The method was validated by analyzing IAEA-SL1 (lake sediment) and NIST-SRM-1572 (citrus leaves). All calculations were performed in Excel. The results revealed most of the elements with good accuracy.

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“…(2.14) no qual considera a contribuição de todas as probabilidades parciais correspondentes de cada ressonância para o valor de energia do nêutron incidente [29][30][31] . [32][33][34][35] O formalismo de Westcott, apresentado em 1958, procura solucionar alguns problemas relacionados com a seção de choque de um espectro de nêutron, descrevendo uma distribuição precisa para as seções de choque que não obedecem a lei-1/ [36] . = Índice que representa a intensidade relativa do componente epitérmico.…”

Section: Fórmula De Breit-wignerunclassified

“…( ) = Função normalizada de densidade de probabilidade de nêutrons térmicos por unidade de velocidade, dada por [32] :…”

Section: Convenção De Westcottunclassified

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Estudo de técnicas estatísticas aplicadas à determinação de parâmetros no método <i>k<sub>0</sub></i> de análise por ativação neutrônica

Ribeiro¹

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The present work aims to improve a code for calculating k0 and Q0 parameters, called COVAR, adding another method of calculating k0 factor and improving the covariance analysis, creating a new version: COVAR v4.1. The present work also aims the development of a new method of calculating the alpha and several k0 parameters in a single least square fit, by means of a novel methodology, using covariance matrices and all partial uncertainties. For the calculations applying this new method, another code was developed, called AKFIT v2.1 which performs linear and non-linear fittings for the determination of alpha and k0 parameters for several irradiations in different periods. We used a database with irradiations in the years 2008 and 2010 performed at the IEAR-1 nuclear reactor of the IPEN-CNEN/SP, by the Nuclear Metrology Laboratory (LMN), corresponding to radionuclides 95 Zr, 65 Zn, 69m Zn, 46 Sc, 140 La and 60 Co and resulting in 21 data sets which were analyzed in order to verify the performance of COVAR4.1 and AKFIT2.1. For COVAR v4.1, the results with the alternative calculation of k0 factor were close to the already existing calculation and were consistent with the literature. For AKFIT v2.1 fittings were performed with both irradiations simultaneously and separately. The fitted models agreed with the literature. The value was 0,0025(83), which agrees with previous results obtained by the LMN. The correlations between the parameters k0 behaved as expected, with smaller values between different elements and greater correlations between equal elements with different energies and using the same comparator measurement. It can be concluded that the proposed methods were able to calculate the values of k0, with AKFIT v2.1 being a new technique in which it is possible to determine two parameters, alpha and k0 at the same time, quickly and accurately. It is expected that AKFIT code can be improved by adding more parameters, such as Q0 and f, by making a complete fitting for the determination of all the main parameters for the k0 NAA method.

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The use of a modified Westcott-formalism in thek o-standardization of NAA: The state of affairs

Cited by 71 publications

References 19 publications

Measurement of the thermal neutron capture cross section and the resonance integral of radioactiveHf182

Measurement of the thermal neutron capture cross section and the resonance integral of radioactiveHf182

Development and implementation of k0-INAA standardization at 10 MW Pakistan research reactor-1

Estudo de técnicas estatísticas aplicadas à determinação de parâmetros no método <i>k<sub>0</sub></i> de análise por ativação neutrônica

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