In this paper we present a complete and detailed computational model of the response of the hybrid Muon Telescope (MuTe), designed to perform muography volcanic studies. This instrument combines two particle detection techniques: first, a muon hodoscope based on two panels of plastic scintillator bars; and a Water Cherenkov detector located behind the rear scintillator panel acting both as a coincidence and a discriminating detector. The simulation model includes: materials, geometries, dimensions, and the photo-sensitiveness of the detectors. The simulation results, in agreement with the measured data, were used to set up the muon detector trigger for the expected energy dependent signal.

ARTI is a complete framework designed to simulate the signals produced by the secondary particles emerging from the interaction of single, multiple, and even from the complete flux of primary cosmic rays with the atmosphere. These signals are simulated for any particle detector located at any place (latitude, longitude and altitude), including the real-time atmospheric, geomagnetic and detector conditions. Formulated through a sequence of codes written in C++, Fortran, Bash and Perl, it provides an easy-to-use integration of three different simulation environments: MagnetoCosmics, CORSIKA and Geant4. These tools evaluate the geomagnetic field effects on the primary flux and simulate atmospheric showers of cosmic rays and the detectors’ response to the secondary flux of particles. In this work, we exhibit the usage of the ARTI framework by calculating the total expected signal flux at eight selected sites of the Latin American Giant Observatory: a cosmic ray Observatory all over Latin America covering a wide range of altitudes, latitudes and geomagnetic rigidities. ARTI will also calculate the signal flux expected during the sudden occurrence of a gamma-ray burst or the flux of energetic photons originating from steady gamma sources. It also compares these fluxes with the expected background when they are detected in a single water Cherenkov detector deployed in a high-altitude site. Furthermore, by using ARTI, it is possible to calculate in a very precise way the expected flux of high-energetic muons and other secondaries at the ground level and to inject them through geological structures for muography applications.

We discuss the geophysical inversion methodology for volcanic muography based on the Simulated Annealing algorithm, using a semi-empirical model of the muon flux reaching the volcano, its surrounding topography and a framework for the energy loss of muons in rock. We determined the minimum muon energy-as function of the arrival direction-needed to cross the volcanic building, the emerging integrated flux of muons and the density profile inside a model of Cerro Machín volcano (Tolima, Colombia) within a maximum error of 1% concerning the theoretical model.

La muongrafía es una técnica de prospección no destructiva que permite la determinación de la estructura interna de grandes estructuras tanto naturales como artificiales, por ejemplo volcanes. Esto es posible al construir una imagen con base en la absorción diferencial del flujo direccional de muones atmosféricos producto de la interacción de rayos cósmicos con la atmósfera. Este trabajo doctoral es desarrollado con el propósito principal de aportar en el avance de la muongrafía como técnica de prospección en Geofísica. El trabajo se compone de dos lineas de trabajo, una experimental y una teórica. La experimental se basa en el desarrollo de un prototipo de detector de astropartículas con base en centelladores plásticos y fotomultiplicadores, para esto se usa una electrónica de adquisición desarrollada para el proyecto AMIGA en el Observatorio Pierre Auger y materiales centelladores de plástico. La segunda linea de trabajo trata del estudio del detector y las estructuras de investigación a través de simulaciones computacionales y modelos teóricos. Durante los dos primeros años se completaron los créditos de cursos solicitados por el doctorado, Ademas se trabajó en el estudio de la respuesta de la electrónica, los pulsos, técnicas de análisis de datos y el acople de fotomultiplicadores con los centelladores. Gracias a esto se avanzo en el desarrollo del prototipo y se investigo la posibilidad de incrementar la resolución espacial a través de la detección sincrónica usando electrónicas conectadas al mismo centellador. Actualmente iniciamos el trabajo en los modelos computacionales, estamos estudiando e investigando con respecto a los candidatos a objetos de estudio, destacando el volcán Copahue, volcán Peteroa y la posibilidad de realizar mediciones bajo tierra.