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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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Abstract  

This paper shows the result of soil-plant relation in samples from Cuban sugar canes of different soil types and cane varieties, using INAA from a thermal reactor. The behavior of minor and trace elements in sugar cane leaves is unifor and independent of sugar cane variety of type of soil. The soil-plant relation shows four principal groups of micro elements, according to their absorption by the plant.

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Abstract  

Thermal and epithermal non-destructive activation analyses have been performed on samples of final molasses from 14 different sugar factories, covering the most important regions in Cuba. From the first measurement after irradiation at the Triga Mark reactor (VTT), the concentration of more than 15 elements is reported. The almost constant elemental composition shows that they can be used equally for different purposes as animal foodstuff and for the manufacture of biotechnological products. This work is part of a research project developed in order to establish a complete characterization of Cuban sugar molasses.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
O. Rizo
,
A. Gelen
,
A. Figuereido
,
N. López
,
K. D’Alessandro
,
J. Arado
, and
J. Beltrán

Abstract  

Rare earth elements (REE) levels in Havana bay surface sediments are determined by instrumental neutron activation analysis. REE contents follow the order: Ce > La > Nd > Sm > Eu, Yb, Tb, Lu. The results shows that REE content in the bay is site depended and suggest that an REE anthropogenic input into the bay occurred. The chondrite and upper continental crust-normalizations confirm the REE enrichment of the bay sediments, respect to the REE content in sediments from the Cuban northwestern coast.

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Abstract  

The nonideality of the epithermal neutron flux distribution at a reactor site parameter () and the thermal-to-epithermal neutron ratio (f) were determined in 3 typical irradiation positions of the Triga Mark III reactor of the National Nuclear Research Institute, Salazar, Mexico, using the Cd-ratio for multimonitor and bare bi-isotopic monitor methods, respectively. This characterization is to be used in theK 0-method of NAA, recently introduced at the Institute.

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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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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:
O. Rizo
,
I. Alvarez
,
E. Herrera
,
L. Lima
,
J. Torres
,
M. Manso
,
M. Lopez
,
M. Ixquiac
, and
D. De La Rosa

Abstract  

A simple non-solid multimonitor HAV-1 for the systematic evaluation of reactor neutron flux parameters fork 0 neutron activation analysis is presented. Solutions of Au, Zr, Co, Zn, Sn, U and Th (deposited in filter paper) are used to study the parameters andf. Dissolved Lu is used to neutron temperature (T n) determination, according to the Wescott's formalism. A multipurpose multimonitor HAV-1 preparation, certification and evaluation is presented.

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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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