Papers by Carlos Manuel Cruz Inclan
Antecedentes: En los estudios del dano radiacional gamma y electronico inducido en materiales sol... more Antecedentes: En los estudios del dano radiacional gamma y electronico inducido en materiales solidos realizados en el CEADEN se recibieron los Premios A.C.C. “Estudio de la Respuesta al Dano radiacional Gamma de Materiales Ceramicos Superconductores” (2002) y “Metodo Clasico asistido por Monte Carlo para la evaluacion del dano radiacional gamma y electronico en materiales solidos” (2012). En esta nueva propuesta, se presenta una descripcion microscopica detallada de los efectos en el ordenamiento atomico provocados por la interaccion de haces de iones radiactivos, cuantos gamma y electrones sobre materiales semiconductores y superconductores. Se han comparados los datos experimentales reportados de los para´ metros de las interacciones hiper- finas medidos en los materiales estudiados con la simulacion numerica microscopica de estos mediante los metodos de la Teoria de los Funcionales de la Densidad, DFT, aspectos nuevos no incluidos en los dos Premios de la A.C.C. que le anteceden.
Efectos de la radiacion gamma del cobalto - 60 en los superconductores de altas temperaturas
Nucleus, 1992
Nucleus, 2011
Se presentan los resultados en la aplicación de la simulación matemática para el estudio de la ef... more Se presentan los resultados en la aplicación de la simulación matemática para el estudio de la efi ciencia cuántica de un detector de silicio cristalino del tipo microbandas, destinado a imagenología médica y al desarrollo de otras aplicaciones como la autenticación y fechado de obras de arte. Se evaluó el efecto de la geometría fuente-detector, de la energía de los rayos X y del grosor de la zona muerta del detector en la efi ciencia cuántica de este dispositivo. Los resultados de la simulación se compararon con el pronóstico teórico y con los datos experimentales disponibles, verifi cándose una adecuada correspondencia. Se concluyó que la confi guración frontal es más efi ciente para energías incidentes menores a los 17 keV, y que la confi guración de borde es la recomendada para aplicaciones que requieran la detección de energías superiores a este valor. También se determinó que la disminución de la zona muerta del detector conduce a un considerable aumento de la efi ciencia para cualquier valor de energía en el intervalo de 5 a 100 keV.
Nucleus, 2019
Some results obtained with the use of Monte Carlo mathematical simulation of radiation transport ... more Some results obtained with the use of Monte Carlo mathematical simulation of radiation transport in Timepix hybrid detectors based on chromium compensated gallium arsenide are presented in this contribution. The MCNPX, GEANT4, SRIM and MCCM code systems were used for this purpose. The in-depth profiles of the deposited energy by the incident photons within the sensor active volume, the shapes and dimensions of the generated charge carriers clouds for different incident energies and specific geometrical conditions were obtained and presented. The 22 Ne ions ranges in the target material for two different energies and the contributions of each energy loss channel were also determined. Finally, for a selected detector irradiated with photons of different energies, the displacement cross sections for each chemical element in the active material, as well as the number of displacements per atoms produced for each atomic species were calculated.
Methodology trends on gamma and electron radiation damage simulation studies in solids under high fluency irradiation environments
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2017
Abstract The present work deals with the numerical simulation of gamma and electron radiation dam... more Abstract The present work deals with the numerical simulation of gamma and electron radiation damage processes under high brightness and radiation particle fluency on regard to two new radiation induced atom displacement processes, which concern with both, the Monte Carlo Method based numerical simulation of the occurrence of atom displacement process as a result of gamma and electron interactions and transport in a solid matrix and the atom displacement threshold energies calculated by Molecular Dynamic methodologies. The two new radiation damage processes here considered in the framework of high brightness and particle fluency irradiation conditions are: 1) The radiation induced atom displacement processes due to a single primary knockout atom excitation in a defective target crystal matrix increasing its defect concentrations (vacancies, interstitials and Frenkel pairs) as a result of a severe and progressive material radiation damage and 2) The occurrence of atom displacements related to multiple primary knockout atom excitations for the same or different atomic species in an perfect target crystal matrix due to subsequent electron elastic atomic scattering in the same atomic neighborhood during a crystal lattice relaxation time. In the present work a review numeral simulation attempts of these two new radiation damage processes are presented, starting from the former developed algorithms and codes for Monte Carlo simulation of atom displacements induced by electron and gamma in
Effects of vacancies on atom displacement threshold energy calculations through Molecular Dynamics Methods in BaTiO3
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2017
Abstract A primary approach for evaluating the influence of point defects like vacancies on atom ... more Abstract A primary approach for evaluating the influence of point defects like vacancies on atom displacement threshold energies values T d in BaTiO 3 is attempted. For this purpose Molecular Dynamics Methods, MD, were applied based on previous T d calculations on an ideal tetragonal crystalline structure. It is an important issue in achieving more realistic simulations of radiation damage effects in BaTiO 3 ceramic materials. It also involves irradiated samples under severe radiation damage effects due to high fluency expositions. In addition to the above mentioned atom displacement events supported by a single primary knock-on atom, PKA, a new mechanism was introduced. It corresponds to the simultaneous excitation of two close primary knock-on atoms in BaTiO 3 , which might take place under a high flux irradiation. Therefore, two different BaTiO 3 T d MD calculation trials were accomplished. Firstly, single PKA excitations in a defective BaTiO 3 tetragonal crystalline structure, consisting in a 2×2×2 BaTiO 3 perovskite like super cell, were considered. It contains vacancies on Ba and O atomic positions under the requirements of electrical charge balance. Alternatively, double PKA excitations in a perfect BaTiO 3 tetragonal unit cell were also simulated. On this basis, the corresponding primary knock-on atom (PKA) defect formation probability functions were calculated at principal crystal directions, and compared with the previous one we calculated and reported at an ideal BaTiO 3 tetrahedral crystal structure. As a general result, a diminution of T d values arises in present calculations in comparison with those calculated for single PKA excitation in an ideal BaTiO 3 crystal structure.
Nucleus, Jun 1, 2009
Radiation damage in terms of atomic displacements in a typical CZT detector used in medical imagi... more Radiation damage in terms of atomic displacements in a typical CZT detector used in medical imaging applications was studied using the Monte Carlo statistical method. All detector structural and geometric features as well as different energies of the photons usually used in the application were taken into account. Considering the MottMcKinleyFeshbach classical approach, effective cross sections of the displacements were calculated, including the number of displacements per atom for each atomic species present in the material and each photon energy considered. These results are analyzed and compared. Finally, the radiation damage on CZT detector is compared to that calculated in a similar detector manufactured with other semiconducting materials. El daño radiacional en términos de desplazamientos atómicos en un típico detector de CZT empleado en aplicaciones de imagenología médica fue estudiado utilizando el método estadístico de Monte Carlo. Se tuvieron en cuenta todas las características estructurales y geométricas del detector, así como las diferentes energías de los fotones usualmente empleados en la aplicación. Considerando la aproximación clásica de MottMcKinleyFeshbach se calcularon las secciones eficaces de desplazamiento, así como el número de desplazamientos por átomo para cada especie atómica presente en el material y para cada energía considerada de los fotones. Estos resultados se analizan y comparan entre sí y finalmente se establece la comparación entre el daño radiacional que tiene lugar en el detector de CZT con el que se manifiesta en un detector similar, pero fabricado con otros materiales semiconductores.
In present paper the dependence of the displacement cross sections of the different species of at... more In present paper the dependence of the displacement cross sections of the different species of atoms in the a-Si:H structure, with the energy of the secondary electrons generated by the X-rays of the typical energies using in medical imaging applications, was calculated using the Mott-McKinley-Feshbach approach. It was verified that for electron energies higher than 1.52 keV it is possible the occurrence of hydrogen atoms displacements, while for the silicon atoms the threshold energy is 126 keV. These results were compared with those obtained for similar detectors but developed with crystalline silicon. With the use of the mathematical simulation of the radiation transport in the matter, the energy spectrum of the secondary electrons was calculated in order to estimate the number of atomic displacements, which take place in the semiconducting amorphous device in working regime. The spatial distribution of the dpa in the detectors volume, as well as its behavior with the depth in the work region are presented and discussed in the text.
The results of the calculations of the displacements per atom distribution induced by the gamma i... more The results of the calculations of the displacements per atom distribution induced by the gamma irradiation on YBa 2 Cu 3 O (7-x) superconductor and Iron slabs up to 15 MeV are presented. Firstly, a calculation procedure for the displacements cross sections and the displacements per atom distributions was introduced, relaying on the application of the energy flux distribution values of secondary electrons, formerly calculated using the Monte Carlo methods based code system MCNPX. Finally, calculation results of displacements per atom distribution were compared with the corresponding energy deposition profiles, obtaining a nearly linear correlation among them at different depth positions for a wide range of Gamma Radiation incident energy.
Monte Carlo calculation of carbon atom displacement damage in C60 fullerene bulk materials irradiated with gamma rays
Nucleus
Nucleus
en materiales masivos de nanotubos de carbono de paredes múltiples irradiados con rayos gamma Res... more en materiales masivos de nanotubos de carbono de paredes múltiples irradiados con rayos gamma Resumen
Cálculo por Monte Carlo del daño por desplazamientos de los átomos de carbono en materiales masivos basados en fullerenos C60 irradiados con rayos gamma
The displacement per carbon atom cross-sections behaviors with the secondary electron and positro... more The displacement per carbon atom cross-sections behaviors with the secondary electron and positron kinetic energy for spherical fullerene C60 molecules are calculated. To accomplish this, the McKinley–Feshbach approach and the Kinchin-Pease approximation were taking into account, using two different displacement threshold energies. The total displacements per atom number generated indirectly by the photons in bulk samples composed of C60 fullerenes is also calculated. Besides, the behaviors of secondary particles contributions with the used displacement threshold energies and incident photon energies are determined. The in-depth distribution of electron and positron contributions and their relationship with the total displacements number are presented and debated. It was found that the positrons contribution to the total atom displacements number is very significant in processes involving the interaction of gamma quanta with energy up to 100 MeV in C60 fullerenes bulk samples.
Superconductor, 2010
The Future applications of new solid state materials, electronic devices and detectors in radiati... more The Future applications of new solid state materials, electronic devices and detectors in radiation environments like Fission and Fusion new generation of Nuclear Reactors, as well as astronomical researches, require a well established understanding about the radiation response of all these items. In addition to foregoing applications the Gamma Radiation ( R) combined effects of energy dependent displacement per atom (dpa) rates and high penetration strength might be attractive for getting a deeper understanding. In particular for high temperature superconductors (HTS) these are interesting for get a better comprehension about their superconducting mechanisms. Quite controversial results have been reported in R damage studies on HTS, especially on regard to the YBa 2 Cu 3 O 7-x (YBCO) superconducting behavior. On this way, the papers dedicated to study gamma irradiation effects on the HTS properties are characterized for a lack of coincidence in criteria and results. Some authors have observed an improvement of the superconducting properties with dose increment (Boiko et at.
Applications of Moessbauer spectroscopy to the structural characterization of minerals and products of the country 's mining - metallurgical industry
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Papers by Carlos Manuel Cruz Inclan