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Abstract  

Concentrations of 38 elements in samples from four important Cuban zeolite beds have been obtained by Instrumental Neutron Activation (INAA) and X-ray Fluorescence analyses (XRFA). In comparison with other analytical techniques good agreement was reached. The concentration values of minor element Ba, Sr, Zn and Mn and 25 trace element (including 9 REE) are at the first time reported in Cuban zeolite. It is important for the zeolite evaluation in different industrial uses.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
O. Díaz Rizo
,
M. Manso Guevara
,
E. Herrera Peraza
,
I. Alvarez Pellón
, and
M. López Reyes

Abstract  

Using the facilities of the Triga Mark III reactor at the NNRI, Mexico and the HAV-1 multipurpose monitor, the reactor power dependency for thek 0-standardization essential neutron flux parameters as: epithermal shape factor (), thermal to epithermal ratio (f) and neutron temperature (T n ) were experimentally obtained. Evaluation of the obtained dependencies shows that it is unnecessary to analyze the possible introduction of correction factors in thek 0-INAA experimental results. A single experimental procedure to determine throughf is suggested.

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Abstract  

Five species of scleractinean corals, extracted from the Northern Havana reef, were studied by INAA and AAS. Selected specimens were sectioned in foot, center and head parts before pulverization procedure. INAA for different irradiation and decay time regimes in a reactor allowed the determination of: Na, Mg, Al, Cl, Sc, Cr, Co, Th, Lu, Eu, Ce, Hf, La and Sr. AAS was performed in a Pye Unicam Model 929 spectrometer. Cu, Mn, Ni, Zn, and Fe were detected. Ca concentration in all species was also established. Obtained Metal-Calcium ratios for Sr, Cu, Zn, Cr, Co, Fe, Mn, Ni and Sc are compared with reported values.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
O. Díaz Rizo
,
M. Manso Guevara
,
E. Herrera Peraza
,
I. Alvarez Pellón
,
M. López Reyes
,
D. López Aldana
, and
F. Garcia Yip

Abstract  

The experimental dependence of the α,f andT n parameters, in function of the water thickness, for different irradiation channels of Triga Mark III reactor, were analyzed. An exponential law for the α(r) dependence was obtained in the neighborhood of the active zone of the reactor numerically modelated using theS n method for 69 neutrons groups, and this dependence is slower in light water reactors than in graphite reactors.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
O. Rizo
,
E. Herrera Peraza
,
M. Manso Guevara
,
I. Pellón
,
M. López Reyes
,
M. Cabrera
, and
M. Montero Cabrera

Abstract  

The main results obtained during the characterization of the Triga Mark III reactor at NNRI, Salazar, Mexico, the development of the nonconventional multimonitor HAV-1, the use of Certified Reference Material (CRM) as multimonitor fork 0-factors experimental determination, and to study the reactor power and slowing-down thickness dependencies of the reactor flux parameters and its influence ink 0-INAA are presented. The experience of thek 0-INAA group at ISCTN, in the application of this analytical technique for different purposes is resumed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
E. Herrera Peraza
,
O. Rizo
,
M. Montero Cabrera
,
A. Hernández
,
R. Folgar
,
M. Cabrera
,
O. Aguilar
,
M. Guevara
,
I. Pellon
,
R. López Duménigo
,
G. González
, and
M. López Reyes

Abstract  

This paper explains chronologically the implementation of thek 0-standardization and other parametric methods in Cuba. Fundamental and applied results in the determination of the most important parameters are obtained, using the IBR-2 at Dubna and Triga Mark III at Mexico reactor facilities. Some modifications in the Stoughton-Halpering convention, and its comparison with the modified Westcott and Høgdahl method are presented. The application of the described methods at the CS-ISCTN low flux facility, using the big samples techniques, is presented.

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