Examinando por Autor "Munévar Espitia, Edwin"
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Ítem Análisis experimental del proceso de redispersión Σ-p en la reacción γd→K+Σ-p para energías del fotón entre 1.9 y 2.3 GeVVélez Saboyá, Carol Stefany; Munévar Espitia, EdwinOne of the main studies in modern physics is strong interaction, interaction between quarks and gluons that allows them to be found together in the hadrons. The study of the reaction γd→K+Σ-p is the objective of the institutionalized research project and may contribute to the study of these interactions, and in particular to the gathering of information in the dynamics of hadrons containing strange quarks due to the lack of information. In this work, a study of the reaction γd→π+π-pn was made as contribution to the research work, due to the fact that this reaction is one of the main sources of contamination in this research. To study the reaction, methods currently employed in particles physics were used, such as particle selection with Δβ, particle reconstruction through missing mass, and others, until the reaction in interest was filtered. The study is made from the analysis of experimental data facilitated by the CLAS collaboration, recorded with the CLAS (CEBAF Large Acceptance Spectrometer) detector during period g13 in the Hall-B of the Thomas Jefferson National Accelerator Laboratory in Virginia, USA.Ítem Aproximación computacional a través de Geant4 de la interacción de 7Li procedentes de la captura de neutrones en células biológicasMedina Martínez, Robinson Steven; Munévar Espitia, Edwin; Leyva Rojas, José AlfonsoThe Boron Neutron Capture Therapy (BNCT) is a therapy that allows tumoral cells selection to later eradicate them without generating great damage in normal tissue. The capture neutron nuclear reaction produces two high-LET particles (α and 7Li) with limited ranges to diameter single cell. Motivated in this approach we have carried out a Geant4 simulation to characterize the reaction 10B(n, α)7Li and study the energy deposited in brain tissue by the 7Li nuclei produced in the final state of that reaction. The results estimated that roughly 64% of events correspond to boron neutron capture. Finally, the simulation with tissue showed that the total energy deposited by 7Li nuclei were approximately 330 MeV.Ítem Aproximación computacional a través de Geant4 de la reacción nuclear de la captura neutrónica por hidrógeno presente en las células biológicasRodríguez Coronado, Diego Antonio; Munévar Espitia, EdwinThe fundamental purpose of this work is to characterize the final state of the reaction that occurs because of the neutron capture by hydrogen present in biological cells. From the particles produced in the reaction will be determined event by event the respective distributions (kinetic energy, momentum, polar angles and azimuthal) and in the same way the dose of radiation that is generated by the energy deposited by the final state of the reaction in the tissuesÍtem Aproximación computacional de la interacción de la radiación gamma procedente de la captura de neutrones en biomoléculas a través de Geant4Tellez Ardila, Diego Alexander; Munévar Espitia, Edwin; Leyva Rojas, José AlfonsoNeutron capture therapy for cancer with 157-Gd carrier (GdNCT) has become promising because of the type of nuclear reaction and the products that occur in this capture process, the products of the reaction are given by different types of phenomena with different ranges of energy; 158-Gd nucleus, gamma rays, internal conversion electrons, auger electrons, and x-rays. A computational study for the characterization of the reaction is performed with the help of the Geant4 tool and we compare the particles and their emitted energies with other computational studies, focusing on the gamma photons emitted in the simulation to estimate the energy and dose deposited in the brain tissue of NIST ICRP. The data obtained in this work are a contribution for the validation of the reaction of GdNCT in Geant4 and to the studies of GdNCT by the results of the energy and dose deposited by the gamma photons rarely studied in this type of therapy as possible agents causing damage to the tumor tissues.Ítem Cálculo de cascada intranuclear como primera etapa en el proceso de fisión nuclear inducida por fotones reales en un rango de energía entre 80 y 600 MeVCarrillo Rodríguez, Carolina; Munévar Espitia, EdwinIn this work, a Monte Carlo code is implemented to determine the distribution of compound nuclei resulting from the interaction between real photons with energies up to 600 MeV and heavy nuclei (Th^{232},U^{233},U^{235},U^{238},Np^{237} ). The code implements the interaction between photons and nuclei based on the Fermi gas model and the intranuclear cascade model where only two photoabsorption processes are taken into account: quasi-deuterón \gamma+ (NN) \rightarrow N+N and one pion production \gamma+ (N) \rightarrow \pi +N. The products of the final state of these processes they can interact in turn within the nuclear environment giving rise to a cascade of particles, which, depending on how many and with what energy they escape from the nucleus, determine the final characteristics of the residual core. As a final result you then get a distribution (In excitation energy, number of nucleons and number of protons) of nuclei residual compounds whose possible mechanisms of de-excitation include, among others, fission nuclearÍtem Calculo de la Eficiencia del Calorímetro Electromagnético para la Detección de Neutrones.Pérez Tovar, Andres Giovanni; Munévar Espitia, EdwinIn this work we present the results for the calculation of the efficiency of the Electromagnetic Calorimeter for neutron detection obtained by analyzing experimental data taken in the Fall of 2006 in the Hall B of the Thomas Jefferson National Accelerator Facility as part of the g13a experimental run period. The experiment consisted of a beam of circularly polarized photons with energies ranging between 0.8 and 2.6 GeV impinging on a deuteron target. The results, in agreement with previous analyses, show that the efficiency scales with the neutron momentum reaching a plateau of roughly 55% at momentum values of 1.8 GeV/c.Ítem Cálculo de la probabilidad de fotofisión de núcleos pesados en un rango de energía entre 0.1 GeV y 1.0 GeVVillamil Clavijo, Sergio Andrés; Munévar Espitia, EdwinThis work has been made with the finality of calculate the distribution of photofission probability for heavy nuclei, which has been induced by real photons in an energy range between 0.1 GeV and 1.0 GeV, through the computational implementation of the intranunclear cascade model. In this model the process of fission is divided in two stages: intranuclear cascade and evaporative cascade. In the first stage, the incident photon starts a intranuclear cascade, in which some involved particles can escape from the nucleus leaving as a result a residual nucleus in a excited estate that is known as compound nucleus. the de-excitation of the compound nucleus is carried out in the second stage starting of different possible mechanism of evaporation´s particles and/ or fission.Ítem El cáncer : una mirada biofísica a través de la membrana celularOrtega Rozo, Leidy Camila; Munévar Espitia, Edwin; Leyva Rojas, José AlfonsoThe cell membrane is mainly composed of a lipid bilayer, which ultimately determines its biophysical properties, since lipids are important elements that regulate several cellular functions, i.e., they serve to protect the cell and regulate the traffic of substances inside and outside it. This regulation is carried out through a complex system of processes that occur through interactions of the membrane components with their surrounding environment, from the molecular point of view, some of the main theories, currently accepted about cancer, indicate that it starts due to the accumulation of alterations in essential genes in the control of cell proliferation and cell death. Cancer affects the cell membrane and these properties are altered, resulting in an imbalance in its initial structure. The fundamental purpose of this work is to study the implications on the cell membrane due to the fundamental purpose of this work is to study the implications on the cell membrane due to the affectations that cancer generates at the cellular level according to these theories with the help of molecular dynamics methods. For this purpose, a computational simulation will be implemented in the Gromacs suite, where we will focus essentially on the characterization of the biomechanics of the membrane due to the changes that are generated in the cell caused by cancer.Ítem Caracterización de la interacción de radiación ionizante neutra a nivel celular mediante una simulación computacional con Geant4Domínguez Castaño, Thalía Vanessa; Munévar Espitia, Edwin; Leyva Rojas, José AlfonsoThis work provides information about the effects that occur in biological tissue models when photons affect them, based on the characterization of the reactions that occur physically. The energy deposited and the absorbed dose in samples of water, brain tissue and skeletal muscle tissue are determined by means of the Geant4 free distribution computational tool. As a result, it can be seen that as the photons of higher energy (hard X-rays) pass through the material, their energy decreases. That is, the characteristic attenuation of the X-rays used for radiotherapy is observed. In tissue, photons with higher energy pass through more easily than photons with low energy, so the deeper it is, the greater the attenuation of the incident beam. The probability that a photon is absorbed or scattered and consequently a certain effect occurs will depend on the incident energy of the photon and the material it passes through.Ítem Caracterización de la reacción de captura neutrónica por 16OSanabria Castro, Luis Stivens; Munévar Espitia, EdwinThe purpose of this work is to study the final state of the nuclear reaction obtained when a neutron beam interacts with targets containing O16, to determine physical quantities of interest such as the kinetic energy of the emitted particles, the energy deposited, the linear transfer of energy, among others. This is done in order to characterize the reaction and verify whether or not the end state particles are harmful to human tissue. The kinematic characterization of the reaction and the amounts mentioned above are determined from simulations developed in the Geant4 computational tool. The simulation implements the interaction of radiation with matter for neutron capture by O16.Ítem Diseño de un modelo de interfaz gráfica como recurso educativo para el estudio de campos vectoriales en electromagnetismo: caso específico campos electrostáticosCaquimbo Muñoz, Cydney Alexandra; Munévar Espitia, EdwinThe visualization of vector fields, represents a tool of great relevance in many scientific disciplines to obtain a clearer and accurate idea of the behavior of a system. The techniques used in the projection of vector fields are of vital importance in areas such as electromagnetism, however, understanding their mathematical representation and physical meanings leads to a certain level of complexity, therefore it is appropriate to use the graphic tools that allow to explain and visualize electrostatic phenomena. Particularly, this work implements a graphical interface model for the visualization of electrostatic fields using ROOT (Data Analysis Infrastructure developed by CERN), numerically solving the Laplace equation through the finite difference method in rectangular coordinates.Ítem Diseño preliminar de un prototipo de un acelerador de iones ligeros para BNCT.Diaz Gómez, Víctor Alfonso; Munévar Espitia, Edwin; Leyva Rojas, José Alfonso; Munévar Espitia, Edwin; Munévar Espitia, Edwin [0000-0002-0578-7717]Currently, the use of medium- and low-energy particle accelerators has been extended to basic research laboratories in materials science, biomedical sciences, among others, and in terms of applications the main ones are in the generation of particle beams for imaging and therapy in different areas of medicine; in the industry they are in the characterization and optimization of materials. In this work, the physical foundations of linear accelerators have been studied, in particular different geometries and configurations of the electrodes for the acceleration system. A specific design was chosen in terms of configuration and geometry of electrodes, for its optimization through computational modeling of the acceleration system. Finally, a preliminary design for a compact linear acceleration column is obtained. Through a combination of experimental data taking and computational modeling, with the help of MATLAB-type calculation platforms, we study the equipotential lines, electric field vectors, and field lines to establish the different trajectories to be followed by deuterium ions, for the particular acceleration lines, given the different configurations and geometries of the electrodes that make up the accelerator column. To model the flow and acceleration of deuterium ions in an accelerating column. The purpose of this work is to determine whether the plasma meniscus and the beam interface can be properly modeled with MATLAB R2020a and thus, successfully predict the deuteron trajectory and beam shape over a wide range. Using MATLAB R2020a and based on experimental measurements of the electrostatic potential for a specific configuration and geometry of the accelerator column electrodes, a matrix of 6000 data characterized in electrostatic potential in 2d, i.e., V = V (x, y) was measured, which was taken as a basis to solve for the electric field: E = −∇V, using a central difference algorithm that allows one to find point by point each component of the electric field (Ex, Ey). Based on the above, we characterized the accelerating column in terms of the equipotential lines and the E field vector in the three acceleration zones, the trajectory of the particles (deuterons) accelerated in the extraction zone, the deuteron motion in the saturation zone, the kinetic energy of the ionized deuterium beam, and a 3D design based on the different columns studied. From the results obtained in this investigation, it is verified that the selected column and its electrode configuration fulfills the conditions to be used in medical application of BNCT. The column is characterized and the blueprint and three-dimensional designs are finally obtained, describing each of its parts and materials for its future construction.Ítem El Efecto Casimir en un sistema de bicapas lipídicasRondón Ramírez, Fidel Leonardo; Rey Ramírez, Jose David; Munévar Espitia, Edwin; Leyva Rojas, José AlfonsoThe Casimir Effect is a phenomenon studied in different branches of physics like nanotechnology, astrophysics and biophysics systems. This work was focused in a bi-layer lipid system upon which a theoretical recompilation of the manifestation of the Casimir Effect on a cellular membrane was performed and to achieve that, it was necessary to breakdown the harmonic oscillator paradigm in the classic regime and shift into the quantic regime. This was done to understand the way in which the electromagnetic field quantizes in the vacuum and then obtain a mathematical expression that correlates the Casimir Effect applying interface conditions. Lastly, alternating the interface conditions it is possible to explain the interaction in the cellular membrane as a consequence of the Casimir Effect.Ítem El efecto fotoeléctrico: un estudio desde el punto de vista semi-clásico que permite su explicación sin hacer uso del concepto de cuanto de energíaRuiz Dagua, Roberto; Munévar Espitia, EdwinIn 1905 Albert Einstein published his article “On a Heuristic View of the Production and Transformation of Light” where for the first time in the history of physics an explanation to the detachment of electrons from a metallic surface as a consequence of the incidence of a light ray on it at a certain frequency is given. The explanation was based on the contribution of Max Planck and his concept of photon as a corpuscle of light. In 1968 Willis E. Lamb Jr and Marlan O. Scully in their article “The photoelectric effect without photons” look for an explanation to the same effect studied and theorized by Einstein without resorting to the concept of photon which is replaced by a classical wave that will be the one in charge of stimulating the electrons of the atom until the point of releasing them. In this case, by using the interaction picture and the time-dependent perturbation theory, a probabilistic explanation of the radiation-matter interaction is presented. In this work, we reproduce the calculations carried out by Lamb and Scully. It is shown how from a semi-classical model the experimental results from the photoelectric effect can be explained in a similar fashion as the model based on the concept of photon does it.Ítem Estudio computacional de la dinámica estructural del ADN, posterior a su interacción con radiación ionizanteSalazar Ortiz, Jaiver Estiven; Munévar Espitia, Edwin; Leyva Rojas, Jose AlfonsoThe following work was carried out at the Pontificia Universidad Javeriana of Bogotá D.C, in collaboration with professors Edwin Munévar and Alfonso Leyva. The DNA study is essential today, understand and assess the damage of this, together with its subsequent biological effects it has an endless number of applications like cancer treatment, radiation protection, gene modification, etc. This work is based on the interaction of DNA with radiation and its study with computational tools in order to understand more about the interactions and the various phenomena that accompany it.Ítem Estudio de las caracterı́sticas magnéticas de ferrofluidos a través de curvas de histéresisRosas Zuluaga, Oscar Andrés; Munévar Espitia, EdwinA ferrofluid (ferromagnetic fluid) has as its main property its response behavior to an external magnetic field. For this case it will make use of the hysteresis loop analysis applied to this type of fluids, the The purpose of this study is to obtain some mathematical models that characterize. Based on the hypothesis: "A ferromagnetic fluid has the same behavior of a ferromagnetic solid?”, which leads to analyze the response to the stimulus inductive on two ferrofluids, built from the combination of filing iron and another with aluminum filings, using glycerin as a fluid to then compare the variations in the parameters. The sample that taken as a reference will be an iron bar that will be used as a core in the coil of the RLC circuit.Ítem Estudio fenomenológico sobre búsquedas de supersimetría en el LHC, usando estados finales de un Leptón, un Jet de radiación de estado inicial y alta pérdida de energía transversalParra Buitrago, Lina Valeria; Vergara Ortiz, Fabio Fernando; Munévar Espitia, EdwinResults on the phenomenological study on searches for new physics in the LHC are presented, using supersymmetric models in the electroweak sector and assuming final states with a lepton (e, μ, τ), an initial state radiation jet and large missing transverse energy. The study was made using simmulated data from supersymmetric models of interest and events coming from the standard model of particles with final states similar to the searched signals. The simmulations were made using the MadGraph software for event generation, Pythia to emulate quark and gluon fragmentation effects (Hadronization processes) and Delphes for detector effects simmulation. The sample analysis was made using C++ in interphase with the Root software. The study presents the event selection criteria to distiguish the signal form standard model processes and thus make the experimental analysis in the LHC.Ítem Evaluación computacional de la contribución de la captura neutrónica por 14N a la dosis absorbida en una muestra de tejido enriquecido con 10BHuertas Avendaño, Hollman Alexander; Munévar Espitia, Edwin; Munévar Espitia, Edwin [0000-0002-0578-7717]Tissue is primarily made up of elements such as hydrogen, carbon, oxygen, and nitrogen. Among them, nitrogen has the largest neutron capture cross section. In a nitrogen neutron capture reaction (NNCR), an energetic proton is emitted that rapidly loses its energy along its path, and a high probability is expected that this released energy will be deposited within the tissue in question. Therefore, even if the percentage of nitrogen (by mass) is on the order of 3% in a typical tissue, its effect is significant and cannot be ignored. In this work, the 14N neutron capture reaction is simulated using the GEANT4 toolkit in order to characterize the reaction in terms of kinematic quantities, deposited energies, and secondary particle dose contribution. Finally, it was found that the absorbed dose associated with the secondary protons of the neutron capture reaction by nitrogen is between the values of 3.1×−14 Gy and 4.7×−14 Gy for energy values of the incident neutron beam between 0.025 and 1.000. eV, respectively. These values establish that the corresponding percentage value is about 17% of the total tissue-associated dose and the absorbed dose associated with secondary 14C atoms from the nitrogen neutron capture reaction is between 2.2×−15 and 3.4× −15 Gy for incident beam energies between 0.025 and 1.000 eV, respectively. These values establish that the corresponding percentage value is close to 1% of the total tissue-associated dose.Ítem Implementación computacional basada en el método estadístico Q-factors para separar señal de ruido en mediciones físicasVásquez Torres, Diego Alejandro; Munévar Espitia, EdwinIn this work we present the statistical and computational considerations for the application of the statistical method called Q-factor to problems in physical measurements. This method allows the signal to be separated from noise in a data distribution, for this a multivariate analysis is done, with which it can be assigned a statistical weight to each event or individual within the measured population. To validate the optimal functioning of the codes developed in C++ language and supported by the data analysis framework ROOT, two applications are made: the first one to the field of high energy physics and the other to extragalactic astronomy, which were simulated with the Montecarlo method. The results that we obtained show an optimal implementation since the statistical values of the Montecarlo distributions contrasted with those obtained by the Q-factors method, show minimal differences.Ítem Una mirada microscópica al espacio de fases de un sistema de pocas partículasMejía Rodríguez, Héctor Fabián; Munévar Espitia, EdwinThe present research work aims at demonstrating how a set of few particles can be modeled as a statistical system, having as a central axis, the trajectories described in the con guration space, through a free-particle experiment. By means of the Hamiltonian and Lagrangian formulation, the distribution of states in the phase space is schematized.