Tesis (Física Atómica, Molecular y Nuclear)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/10867

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New insights into reactions incuded by cluster-structured nuclei: the special cases of 12,13C
(2026-04-08) Garrido-Gómez, Lucas; Fernández García, Juan Pablo; González Álvarez, Marcos Aurelio; Física Atómica, Molecular y Nuclear
This thesis presents an extensive optical model (OM) systematics based on the second version of the São Paulo Potential (SPP2). It is applied to study 4,6He, 6,7Li, 9,10,11Be, and 8B projectiles impinging on a 64Zn target at energies around their respective Coulomb barriers. Within this context, the so-called São Paulo Optical Model Protocol (SP-OMP) is proposed. The real and imaginary strengths of the optical potential (OP) are determined, their correlation is studied, as well as their dependence on the binding energy of the projectile. The sensitivity of the experimental data to the OP is also explored. From the OM analysis, an optimal energy is inferred, at which dissociation channels (transfer and/or breakup) are favored. This prediction was experimentally investigated with the MARS (Modular Apparatus for nuclear Reactions Spectroscopy) spectrometer. Using MARS as a probe, we studied 6Li + 12C nuclear reactions at the National Accelerator Center (CNA), Seville. Measurements of 12C(6Li,4He)14Ng.s. validate the performance of MARS, corroborate OM predictions, and support future experiments at the CNA. The systematic study on cluster-structured projectiles is further extended with new measurements of 12,13C + 64Zn and 119,120Sn, carried out at the Open Laboratory of Nuclear Physics and Applications (LAFNA), in São Paulo (Brazil). Elastic scattering, inelastic excitations, and transfer reactions were measured and analyzed with the SP-OMP and coupled channels (CC) calculations. Particularly, specific pairs of alpha particles derived from 13C breakup were detected in coincidence with good statistics and precision, opening new opportunities for future experiments with exclusive measurements of breakup fragments. This research continued with a new 10B+197Au experiment at the TANDAR laboratory, in Buenos Aires (Argentina), studying direct and one neutron transfer induced breakup, with two or three fragments detected in coincidence. Finally, as a relevant case for nuclear astrophysics, a 4He+ 20Ne experiment was planned and executed at the University of Notre Dame, in Indiana (United States). The results are a benchmark for the Rhinoceros gas target system and for supporting new measurements related to the 12C + 12C fusion process.
Determination of low energy beta-emitters in environmental samples by Liquid Scintillation Counting (LSC) and Accelerator Mass Spectrometry (AMS)
(2026-04-30) García León, José Luis; García León, Manuel; Manjón Collado, Guillermo; Física Atómica, Molecular y Nuclear; Física Aplicada II
The main objective of this work is to develop, optimize, implement, and apply a collection of techniques to the measurement of several increasingly relevant radionuclides in the context of decommissioning of nuclear facilities. Efforts taken towards reducing the Minimum Detectable Activity (MDA) of the techniques used for the determination of radionuclides are a recurring trend of this work, as this was considered relevant for future studies of environmental impact of the decommissioning of nuclear facilities. The first of the radionuclides is 3H, which was analyzed traditionally in our laboratory by means of the electrolytic enrichment sample preparation technique and Liquid Scintillation Counting (LSC) measurement. However, the global levels of 3H have decreased below the MDA achieved in our laboratory, introducing the requirement for an improved technique with lower MDAs to continue monitoring. The implementation, optimization, and validation of this improved LSC measurement technique are presented in this work, in addition to results of determinations performed in drinking water and rainwater. 55Fe and 63Ni are determined sequentially, and it was considered relevant to implement a radiochemical separation technique capable of separating these two radionuclides for their LSC measurement. Although different techniques had been established, this work explores means of reducing the minimum detectable activity by combining different LSC measuring parameters, in addition to spectra analysis techniques. The optimization of the minimum detectable activity is explained in this chapter as well as the validation of the finally implemented technique. In addition, the results of the analysis of two samples collected from nuclear reactors are shown. Finally, a complete procedure for the determination of 14C in nuclear wastewater samples by Accelerator Mass Spectrometry (AMS) was developed. This method aims to use dating equipment for the measurement of this radionuclide, which introduces special challenges regarding the prevention of contamination of this equipment, with the advantage of measuring environmental levels of this radionuclide in greatly reduced counting times. This method was developed to supply the need for the measurement of 14C dissolved in organic and inorganic forms in aqueous samples for decommissioning efforts, thus giving importance to the reduced counting times. The development of the procedure is explained in this work, including the procedures for both chemical forms, in addition to throughout validation works.
Deformation effects in the structure and reactions of weakly bound exotic nuclei
(2026-03-26) Punta de la Herrán, Pedro; Lay Valera, José Antonio; Moro Muñoz, Antonio Matías; Física Atómica, Molecular y Nuclear
This PhD thesis is devoted to the study of the structure and reactions of exotic weakly bound nuclei for which deformation plays a relevant role. It focusses on the description of weakly bound nuclei using deformed two-body models and their application to transfer and breakup reactions. For this purpose, the transformed harmonic oscillator basis has served as a powerful tool to discretise the continuum of unbound states of these nuclei. In exotic nuclei, the ratios of protons to neutrons differ significantly from those in stable nuclei, making them unstable systems with different and special properties. In particular, this work studies light nuclei which are weakly bound due to their excess of neutrons. Some of these nuclei present halo nature, meaning that the system is composed of a relatively compact core and one or two highly delocalised valence particles. On the other hand, their single-particle level schemes may not fit the magic numbers for stable nuclei. The properties of weakly bound exotic nuclei can be investigated by studying direct reactions involving them, which is an active field in nuclear physics due to recent advances in radioactive beam facilities. From a theoretical point of view, structure models that describe the exotic nuclei are required to study these reactions. These models should be sufficiently realistic in the description of the nuclei, but also sufficiently simple towards their inclusion in reaction calculations. In order to achieve both apparently contradictory requirements, it is essential to select the most relevant degrees of freedom. Weakly bound nuclei are often described using few-body models that ignore possible deformations of the fragments. However, for some exotic nuclei, proper consideration of deformation can be crucial. Therefore, the main objective of this work is to describe the structure and dynamics of nuclei composed of a weakly bound neutron and a deformed core.
Weak interactions with Nucleons and Nuclei at intermediate and high Energies: Application to Neutrino Oscillations
(2025-12-05) González Rosa, Jesús; Caballero Carretero, Juan Antonio; Megías Vázquez, Guillermo Daniel; Física Atómica, Molecular y Nuclear
The efforts made in recent years in the development of neutrino oscillation experiments have motivated many theoretical analyses devoted to obtaining accurate descriptions of neutrino-nucleus reactions. These are needed to reduce one of the most important experimental uncertainties, which is associated with nuclear effects, for the determination of oscillation parameters and the violation of the charge-parity symmetry in the neutrino sector. These theoretical models are implemented in Monte Carlo simulators to improve the experimental analyses. The neutrino experiments operate in the 0.5-10 GeV region, where several mechanisms contribute to the nuclear response: from the excitation of collective states at the lowest transferred energies up to the deep inelastic scattering processes at the highest kinematics, embracing also the quasielastic regime, the emission of two nucleons, and the resonance region. This Ph.D. thesis aims to analyze electron and charged-current neutrino cross sections with nuclei at intermediate and high energies, where the dominant channels are the resonance production and deep inelastic scattering. The analysis of these processes will be performed via the SuSAv2 model, based on the scaling phenomenon observed in inclusive electron scattering data and on the RMF theory. This approach is extended to the inelastic region, within the so-called SuSAv2-inelastic model,combining the information of nuclear dynamics from RMF with phenomenological descriptions of the single-nucleon inelastic structure functions from electron scattering data. Furthermore, this inelastic model is extended to the neutrino case by using approximations from QCD, and establishing connections between the electromagnetic inelastic structure functions and the weak ones. The SuSAv2-inelastic model can also be combined with other models to reproduce the resonance region and other inelastic channels. From these combinations, we consider two ways to characterize the inelastic regime. One method makes use of a phenomenological ? scaling function. The second is based on the Dynamical Coupled-Channels approach applied to the resonance region in the so-called SuSAv2-DCC model. In this thesis, these approaches are tested against measurements of inclusive electron-nucleus cross sections on 12C and others throughout the entire energy spectrum to assess their validity. These results provide a solid reference point for the subsequent analysis of charged-current neutrino-nucleus reactions, where these models are validated against inclusive charged-current cross sections at different kinematics from a variety of experiments whose targets are primarily carbon and argon, i.e. T2K, NO?A, MicroBooNE, MINER?A and ArgoNEUT. Similarly, the SuSAv2-DCC model, considering only one pion emission from the resonance ?, can build the neutrino charged-current one pion production cross sections. These predictions are compared with MiniBooNE, MINER?A and MicroBooNE data. As mentioned previously, it is essential to incorporate realistic nuclear models in MonteCarlo event generators. A very common Monte Carlo simulator used in multiple experiments is GENIE. As such, efforts have been made to implement the SuSAv2-inelastic model in GENIE. In this Ph. D. thesis, the preliminary results of this inclusion are presented. In summary, this Ph. D. thesis is an in-depth study of the inelastic electron- and neutrino-nucleus interaction channels using the superscaling approach extended to the inelastic region. These models are tested and validated against the available data from up-to-date neutrino experiments with good agreement with the data, but due to theoretical and experimental uncertainties it is not possible to obtain definitive conclusions. This study will be an advance in our modeling of inelastic lepton nucleus processes and the ability to reduce the uncertainty in present and future high-energy particles and nuclear physics experiments.
Simple models for mesoscopic Systems: from slender Structures to stochastic Resetting
(2025-12-16) García Valladares, Gregorio; Plata Ramos, Carlos Alberto; Prados Montaño, Antonio; Física Atómica, Molecular y Nuclear
The objective of this thesis is to advance the understanding of complex physical phenomena through the lens of statistical physics. Specifically, it addresses two fundamental questions: What types of interactions can induce buckling of slender structures when their temperature is increased? And, how can we devise an optimal strategy for locating a hidden target? The thesis is divided into two distinct parts, both employing mesoscopic descriptions—neither fully microscopic nor fully macroscopic—to capture the essential interactions and behaviours that qualitatively govern the phenomena under investigation. In the first part, we examine the buckling behavior of low-dimensional materials under thermal load. To this end, we develop a comprehensive model that characterizes the system using a minimal setup for mimicking: (i) elastic and electronic degrees of freedom, and (ii) coupling between the elastic and the electronic modes. In the second part, we investigate stochastic resetting processes as a means to formulate efficient search strategies. We explore various resetting mechanisms to understand how to optimise the search performance in real scenarios, where: (i) resetting involves a finite cost, and (ii) the target’s location is only partially known.
Inelastic electronic cross Section modelling of Protons in liquid Water for radiobiology Studies with Monte Carlo Codes
(2025-11-14) Domínguez Muñoz, Antonio Damián; Cortés Giraldo, Miguel Antonio; Física Atómica, Molecular y Nuclear
The main aim of this work is to fill the gaps in the knowledge about the interaction of heavy charged particles with the components of living matter, in particular the interaction of proton in liquid water, with application in Monte Carlo simulation codes for radiation biophysics and radiobiology. The research focuses on modelling the electronic interaction processes that are relevant in proton irradiation of liquid water: ionisation and excitation by both protons and hydrogen atoms, electronic capture by protons and electron loss by hydrogen atoms. The framing, development and achievement of this objective is reported in five chapters. Chapter 1 presents the conceptual framework, explaining first the necessity of understanding the microscopic scale processes in radiobiology to comprehend the biological outcomes of radiation. Second, the physical processes involved and their role within the sequence of events are outlined, and finally, it is justified why Monte Carlo simulation codes are a valuable tool for conducting radiobiology studies. Chapter 2 develops the formalism based on the Plane Wave Born Approximation (PWBA), along with the dielectric formalism, to obtain expressions for the doubly-differential cross section (DDCS) of the aforementioned processes. All these expressions contain a factor called the generalized oscillator strength (GOS), which summarizes the response of the target electrons of the medium to the interaction, being thus its form characteristic of the target. Chapter 3 characterizes the GOS of liquid water, presenting hydrogenic models for the K-shell, and developing a new semiempirical model of the dielectric function for the outer shells, along with an extension for the Bethe ridge through the Born-Compton profile. Chapter 4 addresses the calculation the quantities of interest from the DDCS and presents the models implemented in the Geant4-DNA Monte Carlo code. Additionally, the results obtained with the models developed in this work are analyzed and verified by comparing them with experimental data and other existing models. The chapter ends with the implementation in Geant4-DNA of the ionisation and excitation models for protons above 100 MeV, extending thus the upper energy limit for proton transport from 100 MeV to 300 MeV. Finally, Chapter 5 contains a summary highlighting the main results obtained in this PhD work, the conclusions drawn from them and the future lines of research that would continue this work.
Quantum shape phase Transitions in nuclei: Bohr Equation and Interacting Boson Model
(2025-07-16) Baid, Samira; Arias Carrasco, José Miguel; Oulne, Mustafa; Lahbas, Alaaeddine; Física Atómica, Molecular y Nuclear
The Bohr-Mottelson model (BMM) and the Interacting Boson Model (IBM) are two fundamental approaches in nuclear physics that offer complementary perspectives on the structure and dynamics of nuclei. The Bohr Hamiltonian, formulated in terms of collective variables in five dimensions, is key to describing low-energy quadrupole states and nuclear shape transitions, including spherical, ?-unstable, and axially symmetric deformed configurations. This framework has gained renewed interest due to the increasing availability of experimental data and the discovery of symmetries at critical points that characterize phase transitions in nuclear systems. This thesis develops new solutions for the Bohr Hamiltonian applied to different classes of nuclei, using quasi-exact analytical methods and quantum formalisms. By solving the Schrödinger equation, energy spectra and wave functions are derived, enabling the precise reproduction of experimental observables such as excitation energies and reduced electric quadrupole transition probabilities B(E2). The IBM describes the structure and dynamics of medium and heavy nuclei in the lowest part of their spectrum, truncating the shell model space and treating pairs of nucleons as bosons. Although the IBM is formulated from the outset in terms of second quantization, there is a formalism that provides a geometric view of the model, allowing for comparisons with the shapes obtained in the Bohr model. IBM usually operates with a single configuration (a fixed number of bosons), but the formalism has been extended to include configuration mixing, which enhances its ability to describe nuclear shape coexistence and phase transitions. In this work, the IBM is applied to the Ru isotope chain: i) with a single configuration, and ii) with configuration mixing. The goal is to show the differences between these descriptions in a nuclear region of interest for analyzing the evolution and coexistence of nuclear shapes. Finally, quantum computing techniques are applied to study quantum phase transitions in finite systems. In this work, the Extended Lipkin Model (ELM) is used as a simplified alternative to the IBM. This model has a phase diagram equivalent to that of the IBM and allows exploration of shape evolution and the corresponding phase transitions. For the model’s implementation on quantum platforms, adaptive methods of pseudo-Trotter derived variational quantum optimizer assembly (ADAPT-VQE) were used to address large model spaces. Additionally, a proposal for implementation on a quantum computer is presented, and it is shown how machine learning techniques can be used to classify nuclear shapes, integrating advanced computational tools into nuclear structure studies. The results of this work significantly advance the theoretical understanding of nuclear shape phase transitions, establishing a bridge between theory and experiment. This work has resulted in several peer-reviewed publications and numerous presentations, contributing to the fields of low-energy nuclear physics and quantum technologies.
Measurement of 50Cr and 53Cr Neutron Capture Cross Sections for Nuclear Technology at CERN n_TOF and HiSPANoS
(2024-12-13) Pérez Maroto, Pablo; Guerrero Sánchez, Carlos; Fernández Martínez, Begoña; Física Atómica, Molecular y Nuclear
Nuclear energy has been recognized as crucial in terms of decreasing the CO2 emissions due to carbon sources while satisfying the increasing energy demands worldwide. The associated development towards a more efficient and safer nuclear energy requires nuclear data of high quality, serving criticality safety benchmarks to identify and set priorities about those that need to be improved. In this context, because of its significant abundance in stainless steel, chromium plays an important role in some benchmarks focused on structural materials. Indeed, it has been found that current ∼30% discrepancies in the neutron capture cross sections of 50Cr and 53Cr have an impact of about 1% on keff . Such high discrepancy is related to the fact that the old chromium measurements could suffer from neutron scattering effects, while the most recent one (Guber et al. from 2011) seems to have samples related issues. This was pointed out in the most recent evaluation (INDEN), which proposed an important increase of these cross sections but called for new data to confirm or deny it. For this reason, the Nuclear Energy Agency (NEA) opened an entry in its High Priority Request List (HPRL) to measure the 50,53Cr (n,γ) cross sections with an accuracy of 8 to 10%between 1 and 100 keV, with emphasis on the region below 10 keV. This work is dedicated to the measurements carried out as a response to the NEA request. First, a time-of-flight measurement was performed at the n_TOF facility of CERN (Switzerland), in which the capture yield of both isotopes was measured and a new set of resonance parameters has been proposed. In addition, for the first time a neutron activation measurement of 50Cr was performed at the HiSPANoS facility of CNA (Spain) to determine its MACS at kT = 30 keV. The results from both experiments are in agreement, while the comparison to the evaluations indicates a clear cross section overestimation by 20-40% in the recent INDEN evaluation for both isotopes. When all evaluations are considered, our results are in better agreement with CENDL-3.2, which is the only one not considering the most recent data by Guber et al. (2011). With these findings, the new differential and integral cross sections reported herein should contribute to impulse new evaluation effort and solve the chromium puzzle.
Láminas delgadas funcionales orgánicas y de óxidos ultraporosos por Tecnología de Plasma
(2024-12-13) Obrero Pérez, José M.; Sánchez Valencia, Juan Ramón; Barranco Quero, Ángel; Física Atómica, Molecular y Nuclear
La investigación desarrollada en esta Tesis se centra en el desarrollo de películas delgadas funcionales nanoestructuradas mediante técnicas avanzadas de deposición asistida por plasma remoto (RPAVD) y etching por plasma (SPE). La metodología utiliza películas delgadas poliméricas de plasma que contienen cationes metálicos sintetizados por RPAVD. La exposición de estas capas (utilizadas como material de sacrificio) a procesos de etching por plasmas oxidantes permite la eliminación de la parte orgánica de la película y la generación de un esqueleto inorgánico altamente poroso, que les confiere propiedades singulares como una mayor área superficial, baja densidad y alta permeabilidad, haciéndolas ideales para aplicaciones en catálisis, sensores de gases, biomedicina y dispositivos optoelectrónicos. Esta metodología presenta ventajas respecto a los métodos tradicionales, tales como la eliminación de disolventes tóxicos y la reducción de temperaturas de síntesis, permitiendo obtener materiales con propiedades ópticas y eléctrónicas ajustables, así como un control más preciso de la morfología y composición de los materiales. Como resultado de estos estudios, se ha desarrollado una metodología general para la fabricación de películas delgadas de óxidos conformales con valores de porosidad similares a los reportados para aerogeles inorgánicos sintetizados por rutas químicas y procesos de extracción supercrítica. La deposición por plasma permite integrar estos materiales porosos en superficies complejas y a bajas temperaturas, aspecto particularmente ventajoso en aplicaciones donde los sustratos son sensibles al calor como en la electrónica flexible. Este proceso de fabricación es novedoso y de naturaleza general, ya que permite la fabricación de óxidos tipo aerogel con diferentes composiciones, dependiendo del precursor utilizado. El proceso se ha desarrollado y refinado para diseñar y fabricar dos óxidos funcionales: óxido de titanio y óxido de vanadio. En el primer caso , se ha estudiado la fabricación de óxido de titanio tipo aerogel para su uso como películas ópticas fotoactivas antirreflectantes, superficies superomnifóbicas y capas de transporte de electrones en celdas solares de perovskita. Para el óxido de vanadio termocrómico, se han desarrollado películas termocrómicas nanocristalinas tipo aerogel de VO2, partiendo de la síntesis de películas precursoras de V2O5. En este caso, se han sintetizado con éxito películas altamente transparentes en el rango visible con un excelente rendimiento termocrómico, resolviendo el problema característico de la falta de transparencia en películas compactas de VO2. Además de estos dos óxidos, también se han realizado estudios sobre óxidos de hierro, galio y silicio para demostrar la generalidad del método y mostrar su potencial. Esta Tesis se completa con el desarrollo de capas conformales dieléctricas por RPAVD basadas en la molécula de adamantano para pasivar superficies de TiO2 mesoporoso y optimizar el comportamiento de las celdas solares de perovskita. También se ha estudiado la encapsulación de óxido de vanadio termocrómico utilizando estas capas RPAVD basadas en adamantano para aumentar la resistencia mecánica y prevenir la oxidación ambiental. El estudio presentado en esta Tesis representa una extensión del trabajo reciente del laboratorio de “Nanotecnología en Superficies y Plasma” en el campo de los polímeros funcionales y, más específicamente, la expansión de la técnica RPAVD a la fabricación de óxidos conformales ultraporosos funcionales. Cabe destacar la escalabilidad industrial de estos procesos de fabricación y, en particular, las oportunidades que abren para múltiples aplicaciones futuras. Este aspecto se está desarrollando en proyectos de investigación recientes dentro del grupo de investigación relacionados con materiales para la energía, supercondensadores y superficies para aplicaciones espaciales.
Control and Optimisation of irreversible Processes in non-equilibrium Systems
(2024-10-25) Patrón Castro, Antonio; Prados Montaño, Antonio; Plata Ramos, Carlos Alberto; Física Atómica, Molecular y Nuclear
This thesis is devoted to the study of physical systems embedded within the field of non-equilibrium statistical mechanics. Specifically, the state of the systems of interest constitutes a stochastic process that can be externally driven by a set of controllable parameters. On the one hand, for systems in contact with a thermal bath, we have studied the emergence of strong memory effects and glassy behaviour upon varying the bath temperature, and how these are related to the existence of non-equilibrium attractors governing the dynamics. On the other hand, for overdamped harmonic systems, we have studied the problem of minimising the connection time between arbitrary stationary---equilibrium or non-equilibrium---states, by suitably varying either the bath temperature or the stiffnesses of the potential.
Procesos de nucleación y autoensamblaje de moléculas orgánicas sobre superficies
(2024-10-07) Orozco-Corrales, Noel; Espinós Manzorro, Juan Pedro; Sánchez Valencia, Juan Ramón; Lambert, Richard M.; Física Atómica, Molecular y Nuclear
La ciencia de superficies estudia fenómenos físicos y químicos que ocurren en una interfase, incluyendo líquido-gas, sólido-líquido, sólido-gas y, la que atañe a esta tesis, sólido-vacío. La superficie juega un papel fundamental en la ciencia de materiales ya que es la responsable de numerosas propiedades como son la fricción, corrosión, ópticas o catalíticas, entre muchas otras. Esta tesis se enmarca en el estudio de procesos físico-químicos entre superficies metálicas monocristalinas y moléculas orgánicas o metal-orgánicas de interés en distintos campos, tales como la electrónica, catálisis y dispositivos ópticos o fotónicos, entre otros. Las técnicas de caracterización utilizadas son ampliamente usadas en el estudio de superficies: la microscopía de barrido túnel (STM) y la espectroscopía fotoelectrónica de rayos-X (XPS). En concreto, en esta Tesis se han estudiado los siguientes procesos: - Estudio de la reacción de homoacoplamiento y acoplamiento cruzado Sonogashira entre fenilacetileno y clorobenceno sobre Ag(100) en condiciones de ultra alto vacío. - Estudio de la reacción de homoacoplamiento Glaser-Hay de fenilacetileno sobre Ag(100) y el papel del oxígeno en dicha reacción, tanto en condiciones de ultra alto vacío como en condiciones prácticas. - Estudio de los efectos del tratamiento con plasma en dos aspectos: i) cómo afecta el pretratamiento con plasma oxidante a un sustrato de Ag(100) al crecimiento de una molécula con conjugación ?, en concreto ftalocianina de zinc; ii) el efecto de un tratamiento con plasma sobre una capa ultra fina de ftalocianina de zinc sobre Ag(100).
Development of advanced numerical Tools for fusion reactor Diagnostics and nonlinear modeling of Plasma Dynamics
(2024-09-18) Oyola Domínguez, Pablo; Viezzer, Eleonora; Birkenmeier, G.; Física Atómica, Molecular y Nuclear
A precise control and understanding of the plasma dynamics is crucial for future fusion reactors. The complex dynamics and the harsh environments in magnetic fusion devices, such as tokamaks, require the most advanced modeling techniques both from the theoretical predictive side, to the experiment diagnosis and data analysis. In this PhD thesis, a two-fold approach is presented to advance in the understanding and control of the plasma dynamics. From the experimental side, a novel diagnostic, the imaging Heavy Ion Beam Probe (i-HIBP), has been installed, commissioned and operated at the ASDEX Upgrade tokamak during this thesis. The i-HIBP has been installed in the ASDEX Upgrade tokamak (Germany), in collaboration with the Max-Planck Institute for Plasma Physics. This diagnostic uses heavy alkali as probe ions that, after passing through the plasma, reach a scintillator plate. The footprint on the scintillator encodes information of the plasma density and the electromagnetic perturbations along their trajectories in the plasma. In this work, the modeling tools have been developed and applied to reproduce the signals and extract relevant information on edge plasma density and current density perturbations. In particular, it is shown that even in a low signal-to-noise ratio scenario, the plasma density can be reconstructed at the plasma edge with an excellent radial resolution. On the theoretical and modeling side, this PhD thesis focuses on studying the fast ions(suprathermal particles), as they will play a key role in the fusion power generation: they are envisioned to be the most important source of energy (heating) and momentum. Fast-ion losses can lead to a decrease in the power throughput and, when localized, could potentially damage the first wall components. A renewed interest in an alternative tokamak scenario, based on the negative-triangularity shaped plasma, has arisen the question of the fast-ion confinement and the possible instabilities that they could suffer. In this work, this topic is addressed by using one of the most advanced hybrid kinetic magnetohydrodynamics codes in the community, the MEGA code, to study the behavior and transport of a Toroidal Alfvén Eigenmode (TAE). The results presented here show that the confinement of the fast-ions is more resilient
Low Dimensional Optoelectronic Devices enabled by Vacuum and Plasma Technologies
(2024-07-30) Castillo Seoane, Javier; Sánchez Valencia, Juan Ramón; Borrás Martos, Ana Isabel; Física Atómica, Molecular y Nuclear
The need for energy-efficient technologies is critical for confronting urgent environmental challenges. This Ph.D. thesis explores the development of nanostructured optoelectronic devices with enhanced efficiency, durability, and functionality using plasma and vacuum technologies. It focuses on synthesizing and integrating low-dimensional nanostructures, such as 1D nanowires, nanotubes, core@(multi)shell systems, and nanowalls, through multistep soft-template methods and glancing angle deposition (GLAD). These materials were integrated into photovoltaic devices and photodetectors, demonstrating improved stability and multifunctionality. The research not only highlights the transformative potential of vacuum and plasma technologies in creating advanced optoelectronic devices but also paves the way for more sustainable, energy-efficient technologies.
Imaging neutral particle analyzer for fast-ion transport measurements in the ASDEX upgrade tokamak
(2024-03-19) Rueda Rueda, José; García Muñoz, Manuel; Viezzer, Eleonora; Física Atómica, Molecular y Nuclear
In future fusion reactors, suprathermal particles (fast ions, FI) will play a key role in the generation of fusion power as they are an important source of energy (heating) and momentum (current drive). A loss of their confinement will lead to a decrease in reactor performance, and, when localized and intense, to damage in the first wall components. Understanding the mechanisms behind the suprathermal particle transport and losses is capital for achieving a future fusion power plant. One of the main observed causes for the FI transport and eventual loss is their interaction with a wide range of electromagnetic fluctuations. An accurate understanding of the fast-ion behavior in the presence of magnetohydrodynamic fluctuations is required for achieving a good fast-ion confinement. To this end, new diagnostics are being developed to measure the fast-ion distribution over a broad region of the phase space with high resolution. In this PhD thesis, an Imaging Neutral Particle Analyzer (INPA) has been installed and operated at the ASDEX Upgrade (AUG) tokamak, located at the Max Planck Institute for Plasma Physics in Garching (Germany). INPA employs the operational principles of both fast-ion loss detectors (FILD) and neutral particle analyzers (NPA) to measure the fast-ion distribution in energy and radius. This diagnostic system analyses fast neutrals that emerge from charge exchange (CX) reactions between fast ions and neutral particles. These fast neutrals are ionized through an ultra-thin carbon foil located within the in-vessel optical head and are deflected towards a scintillator using the local magnetic field of the tokamak. From the impinging location of a particle on the INPA scintillator, its energy and velocity projection along the magnetic field lines can be deduced. The use of an active source of neutrals enables the direct correlation of this velocity projection with the radial position of the fast ion. The FILDSIM code, which facilitates the calculation of synthetic signals for the FILD diagnostic, has undergone a major upgrade to handle the INPA diagnostic. This upgrade includes a model for simulating the scattering and energy loss of fast neutrals within the carbon foil. Additionally, it encompasses a model for estimating the scintillator yield and the capacity to conduct tomographic reconstructions. This updated code has been benchmarked against experimental data during the 2021-2022 campaign, showing an excellent agreement between simulations and measurements. Tomographic inversions also agree with neoclassical calculations during MHD quiescent phases. Fast-ion acceleration during second harmonic ion cyclotron resonance heating has been characterized and compared to simulations. The agreement found serves as validation of these codes for their extrapolation to future machines. Fast-ion flows driven by Alfvén eigenmodes have been measured for the first time at ASDEX Upgrade. The observed flows align well with the theoretical models and with fullorbit simulations.
Compact neutron sources for Nuclear Physics: from accelerator-based to laser-driven neutron beams
(2023-12-14) Millán Callado, María de los Ángeles; Fernández Martínez, Begoña; Guetrrero Sánchez, Carlos; Física Atómica, Molecular y Nuclear
Pulsed neutron beams are a valuable tool in nuclear physics with applications in a wide variety of fields, including fission and fusion, astrophysics, homeland security, medicine, cultural heritage, avionics, and other industrial or research applications. Despite the potential use of neutron beams, the transfer of knowledge outside large research centers is limited by the huge size and complexity of conventional high-intensity neutron sources and the progressive shutdown of research reactors. Recently, the neutron beams user community is focusing its attention on developing small-scale and compact neutron sources as a complement to major facilities to fully exploit all the possibilities of these techniques. In this context, laser-driven ion sources are garnering the interest of the nuclear physics community due to the fast development of ultra-short (~fs) and ultra-high power (> 1019 W/cm2) lasers and their applications as compact particle accelerators. Laser-driven neutron sources (LDNS) are particularly attractive for nuclear physics applications based on the time-of-flight technique thanks to their short pulse length and high instantaneous flux. There are several recent works about neutron production by laser reaching fluxes per pulse competitive to those of conventional neutron sources, but there is a lack of studies in terms of their application to nuclear physics experiments. Laser-driven neutron applications will have to rely on detection systems that are commonly used in nuclear physics experiments with conventional neutron sources, and whose behavior needs first to be characterized in the environment resulting from the laser-plasma interaction and the particularities of a laser-driven source. In this context, there has been a lot of effort aimed at mitigating the impact of the harsh prompt radiation and the electromagnetic background in sensitive neutron diagnostics, mostly based on single-shot PW-class and TW-class lasers at high repetition rates. However, the typical current-mode operation of neutron detectors in LDNS experiments is not suitable to carry out neutron-induced nuclear reaction experiments, since those require the detection of single signals corresponding to the observables from the individual reactions and processes involved. In this thesis, a study on the feasibility of time-of-flight nuclear reaction measurements in the complex environment of an LDNS has been carried out at the DRACO laser facility of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in Dresden, Germany, producing neutron shots at 0,02 Hz in a high-power system in stable conditions. In addition to conventional scintillators and bubble detectors operated in current/integrated mode, multi-shot neutron production made it possible to use a neutron and charged particle detector with low efficiency, i.e. diamond detector, to measure individual signals from fast neutron interactions. This itself is a milestone in the path towards nuclear physics time-of-flight experiments at LDNS and, to achieve it, a dedicated signal analysis routine had to be developed for the diamond detector. The characterization of the neutron source resulting from two different nuclear reactions, Cu(p,n) and LiF(p,n), by means of the individual signals and the time-of-flight technique, has been positively validated against Monte Carlo simulations, confirming the feasibility of measuring single fast neutron interactions at an LDNS. The results obtained at DRACO, the characteristics of the LDNS, and the performance of the detectors are compared and contextualized with the results obtained in the commissioning of a conventional accelerator-based compact neutron source: the HiSPANoS neutron source at Centro Nacional de Aceleradores (CNA) in Sevilla, Spain. In this facility, different fast neutron beams have been obtained by means of Be(d,n) and Li(d,n) reactions in thick targets, which provide white neutron beams up to 10 and 20 MeV respectively, as well as of D(d,n) reactions, covering an energy range between 2 and 6 MeV with quasi-monoenergetic neutron beams. The characterization was carried out with conventional fast organic scintillators and applying the time-of-flight technique again. Based on the results and the comparative analysis of both experiments, the neutron production per pulse at DRACO has been established to be superior. Also of high interest, the main drawbacks and issues faced at DRACO are identified, and possible solutions are proposed as a first step towards experiments on fast neutron-induced reactions at laser-driven neutron sources.
Semi-inclusive neutrino-nucleus reactions at intermediate energies
(2023-11-24) Franco Patiño, Juan Manuel; Bárbaro, María Benedetta; Caballero Carretero, Juan Antonio; Física Atómica, Molecular y Nuclear
The discovery of neutrino oscillations in 1998 by the Super-Kamiokande experiment opened a new frontier in particle physics. Past, ongoing, and forthcoming experiments are dedicated to unraveling the mechanisms responsible for neutrino oscillations by measuring the physical parameters governing this phenomenon. As for now, the neutrino mass hierarchy remains unknown, yet it is an important physical information. Additionally, neutrino oscillations have hinted at the existence of charge-parity violation within the lepton sector. To determine the presence of such violation, a fundamental parameter of the PMNS paradigm needs to be measured. Presently, accelerator-based neutrino experiments are actively gathering data, while new experiments are in development, all geared towards quantifying the degree of CP violation present in neutrino oscillations. One of the main limiting systematic errors in neutrino oscillation physics comes from our limited knowledge of neutrino-nucleus interactions. To help to constrain nuclear effects for the modeling of neutrino-nucleus interactions and improve the reconstruction of the neutrino energy for oscillation experiments, in this thesis we have studied semi-inclusive neutrino interactions with complex nuclei at intermediate lepton energies, i.e., neutrino beam energies ranging from 0.5 up to 10 GeV. Due to the kinematics of the particles involved and the complexity of the interaction, we have developed a fully relativistic and quantum mechanical model able to describe not only inclusive but also semi-inclusive electron and neutrino reactions with complex nuclei. Starting with Chapter 1, an introduction to neutrino oscillations, acceleratorbased neutrino experiments and neutrino-nucleus interactions is presented. Chapter 2 is mainly focused in the general definition of a semi-inclusive neutrinonucleus reaction and the analysis, from a theoretical point of view, of semiinclusive results using different models of the nucleus, but neglecting the effects introduced by final state interactions. Chapter 3 is entirely dedicated to the description of the one-proton knockout process, a type of semi-inclusive reaction, using a fully relativistic and quantum mechanical model of the nuclear dynamics and final-state interactions called relativistic distorted-wave impulse approximation. In Chapter 4 we review the current approach used by neutrino event generators to describe semi-inclusive reactions. Different approximations for the description of semi-inclusive reactions are compared with semi-inclusive cross section measurements performed by different international collaborations, like T2K, MINERvA and MicroBooNE, in Chapter 5. Finally, in Chapter 6 a summary and the conclusions of this thesis are presented.
3D hybrid kinetic-MHD modelling of the interaction between Edge Localised Modes and Energetic Particles in the ASDEX Upgrade tokamak
(2023-11-03) Domíngez Palacios Durán, Jesús José; Futatani, S.; Toscano Jiménez, Manuel; Física Aplicada III; Física Atómica, Molecular y Nuclear
Nuclear fusion is a clean and virtually unlimited energy source that might meet the large energy demands in the near future. For the successful realization of a future fusion reactor, Edge Localized Modes [ELMs, periodic magnetohydrodynamic (MHD) instabilities that expel particles and energy from the plasma in a similar way to solar flares from the edge of the Sun] must be kept under control to avoid the large heat fluxes onto the plasma facing components, which will reduce the lifetime of the reactor. Although the ELM nature is well understood, its behavior and consequences in a burning plasma with a significant fraction of energetic (supra-thermal) ions is still missing. Energetic ions, which are produced by auxiliary heating systems or by the fusion reaction, are an essential source of momentum and energy that must be kept well confined until they slow down to the plasma bulk through Coulomb collisions. However, energetic ions are prone to a rich variety of wave-particle interactions due to their large velocities and long mean free paths, that can lead to an efficient exchange of energy and momentum with a broad spectrum of MHD fluctuations. This thesis shows the first nonlinear hybrid kinetic-MHD simulations of ELMs, aimed to study the self-consistent interaction between ELMs and fast-ions, applying the nonlinear hybrid kinetic-MHD code MEGA to an ASDEX Upgrade plasma. During this thesis, the numerical set up of MEGA code has been modified to study both the thermal plasma and fast-ion dynamics at the plasma edge. First, simulations without fast-ions are performed to simulate the basic physics of an ELM crash. In the linear phase, it is found that high-n ballooning modes are more unstable. The nonlinear coupling between the modes is observed in the early non-linear phase. The ELM crash is finally simulated, observing the plasma filaments that are ejected from the plasma region, with the consequence of the flattening of the driving sources. Fast-ions are then included in the model and different parameters of the fast-ion distribution have been scanned to understand how fast-ions and ELMs interact with each other. First, single-n simulations, which includes n = 0, 10 modes, are performed. When the fast-ion distribution peaks at the plasma core, both the ELM at the plasma edge and an Energetic Particle Mode (EPM) at the plasma core are simulated. Only when the fast-ion distribution is closer to the plasma edge, a strong interaction between ELMs and fast-ions is observed. In such a case, the simulations indicate that fast-ion kinetic effects have a strong impact on the spatio-temporal structure of the ELM. The interaction mechanism between the ELM and fast-ions has been analyzed studying the nature of the power exchange between ELMs and fast-ions in the phase-space of the energetic particles. Although the ELM is driven by the thermal plasma pressure gradient, a resonant interaction between the drift orbits of the edge fast-ion population and the ELM electromagnetic perturbation leads to a net wave-particle energy and momentum exchange that determines the resulting ELM spatio-temporal structure. An Energetic particle driven Geodesic Acoustic Mode (EGAM) appears after the ELM in the hybrid kinetic-MHD simulations, whose mode structure is strongly impacted by the ELM and that might help to understand the frequency pattern of the n = 0 mode observed in NBI heated plasmas. A hybrid kinetic MHD multi-n simulation of ELM, which includes n = 0, …, 10 modes, has also been performed to account for the wave-wave coupling in the presence of fast-ions. Without fast-ions, n = 9, 10 modes are the most unstable modes. In the presence of fast-ions, the most unstable mode number is n = 8 with an energy almost 5 times larger than the mode energies obtained in the MHD multi-n simulation without fast-ions. The shifting of the most unstable mode is due to a large energy exchange between n = 8 mode and energetic ions. The impact of the fast-ion kinetic effects on the spatio-temporal structure of high-n modes is qualitatively the same in both the multi-n and single-n hybrid kinetic-MHD simulations. A strong power exchange between the ELM and fast-ions is also found in the multi-n simulations. In this simulation, a resonance overlap between the different toroidal modes is probably taking place, given the closeness of the resonances associated to the different modes. Additionally, in the multi-n simulations, a strong impact on the spatio-temporal structure of low-n harmonics has been observed. The simulations presented in this manuscript reproduce some outstanding ELM observations in low collisionality plasmas with large fast-ion contents that feature abrupt and large ELM crashes.
Towards PET range verification in proton therapy: new cross sections for improved accuracy
(2023-04-24) Rodríguez González, María Teresa; Guerrero Sánchez, Carlos; Quesada Molina, José Manuel; Física Atómica, Molecular y Nuclear
Proton therapy is a form of radiotherapy that allows maximizing the deposited dose inside the tumour while reducing the dose in the healthy tissues, thanks to its superior depth-dose distribution when compared against conventional photon therapy. Uncertainties in the beam range, however, require considering additional safety margins to ensure the tumour coverage and the non-irradiation of surrounding tissues. In this context, a method to validate the range of the beam in-vivo should lead to better treatment designs, minimizing normal tissue complications and hence improving tumour control. Among the different options proposed for this, PET range verification has received a very significant attention in the last 15 years and has even been clinically tested. Correspondingly, there is a worldwide effort to make it feasible and reliable aiming at its eventual clinical implementation. PET range verification requires a comparison of the measured (with a PET scanner) and expected (from Monte Carlo simulations) β + activity distributions produced by the proton field in the patient’s body, which can be, depending on the half-life of the isotope involved, online (ms to seconds) or offline (minutes). The accuracy of the mentioned expected activity distribution is based, among others factors, on the accuracy of production cross sections resulting in β + emitters used as input in the Monte Carlo simulations, which are 11C with t1/2=20.36 min, 13N with t1/2=9.97 min, and 15O with t1/2=122 s, produced in C, N y O, 12N with t1/2=11.0 ms, produced in C, 38mK with t1/2=926 ms, produced in Ca and 29P with t1/2=4.14 s, produced in P. Unfortunately, the situation is such that experimental data are completely missing for some reactions of interest and there are sizable discrepancies between the data sets available in EXFOR. Therefore, both the IAEA nuclear data evaluators and the medical physics community have call for a significant improvement of these nuclear data in order to reduce the uncertainties in the estimation of the activity distributions to a level that allows detecting beam range variations within 1 mm. In this context, the work developed in this thesis consists on the determination of the cross sections up to 200 MeV of the reactions involved in PET range verification to improve the simulations of the expected activity distributions in the patient. The reactions of interest are 11 in total, producing either the long-lived isotopes via 12C(p,x)11C, 12C(p,x)13N, 14N(p,x)11C, 14N(p,x)13N, 14N(p,x)15O, 16O(p,x)11C, 16O(p,x)13N and 16O(p,x)15O, or the short-lived isotopes via 12C(p,x)12N, 40Ca(p,x)38mK and 31P(p,x)29P. In this manuscript, a description of the experiments, analyses and results is presented. The experiments have been performed at the National Center of Accelerators (CNA, Spain), the West German Proton Therapy Center (WPE, Germany) and the Heidelberg Ion-Beam Therapy Center (HIT, Germany), using three different detection systems (PET scanners, NaI and LaBr3 detectors). The data presented herein have been obtained either by the multi-foil activation technique combined with the measurement with a PET scanner or by single foil activation and conventional detectors. A wide variety of strategies have been implemented to validate and ensure the accuracy of the results. In order to assess the impact for PET range verification of these new cross sections, in some cases measured for the first time, they have been used to simulate the β + production and activity profiles (as a function of time) of each isotope in tissue-equivalent phantoms and compared with the ones calculated with the current evaluations. The results illustrate the importance of new data and the need of revised evaluations for a reliable implementation of PET range verification. This is specially relevant for some of the reactions producing long-lived isotopes, but it is of upmost importance for reactions producing the short-lived isotopes needed for online verification, as these are the first cross section data ever. Overall, the new cross sections data base is expected to have an impact on the eventual implementation of both offline and online PET range verification aiming at adaptive proton therapy treatments.
Study and characterisation of semiconductor radiation detectors using the IBIC technique
(2022-12-19) García Osuna, Adrián; García López, Francisco Javier; Jiménez Ramos, María del Carmen; Física Atómica, Molecular y Nuclear; Física Aplicada II
The work carried out in this thesis focuses on the study of radiation detectors based on semiconductor materials by applying the technique known as Ion Beam Induced Current (or IBIC technique). Radiation and particle detectors in general are essential in practically any experiment or application in nuclear physics (high energy accelerators, nuclear reactors, medical applications, etc.) and, as experiments and applications grow in complexity and requirements, detectors must also constantly improve in performance and features to be able to meet their needs. It is therefore necessary not only to improve detector manufacturing technology, but also to improve the technology related to the various methods for the study and characterisation of new detectors (IBIC, EBIC, TCT, TPA, etc.). The technique used in this thesis, i.e., the IBIC technique, is a powerful and versatile tool that uses focused ion beams for the characterisation of semiconductor radiation detectors. In this thesis, the IBIC technique has been applied in the context of three different research projects, each with different motivations and objectives and, therefore, each detector has a completely different design to offer specific features. However, thanks to the IBIC technique, it is possible to study and characterise all of them and obtain information that would not be possible with other techniques, getting to understand and deepen the physical mechanisms underlying their operation. On the one hand, the IBIC technique was applied to a commercial silicon detector in order to study the formation and evolution of defects caused by radiation in this material. This work is part of an IAEA Coordinated Research Project and the results will provide experimental data to extend current defect dynamics simulation models beyond existing time limits. On the other hand, the IBIC technique was used to study and characterise innovative silicon carbide (SiC) detectors manufactured at the Instituto de Microelectrónica de Barcelona, which are designed to operate under extreme temperature and radiation conditions in general and in future fusion reactors in particular. These results will be used to study the optimal operating point and its application limits, validating its use for the required application. In addition, this technique allows further study of various physical phenomena occurring within the detector, such as the reduction of the charge carriers mean lifetime, or the reduction of the mean energy required to generate an electron-hole pair in SiC as a function of temperature. Finally, the IBIC technique and also the Time-Resolved IBIC (TRIBIC) technique were used to study the phenomenon of charge density-induced gain suppression in Low Gain Avalanche Detectors (LGADs) fabricated at the Instituto de Microelectrónica de Barcelona. These detectors are aimed to detect minimum ionising particles in the future High-Luminosity Large Hadron Collider (HL-LHC) at CERN. Our results will help to better understand the phenomenon of charge multiplication and the role of the ionization charge density in the gain value. This information is of vital importance in order to correctly interpret the data provided by future HL-LHC experiments.
Characterization of main ion properties for the optimization of future fusion power plants
(2022-12-19) Cano Megías, Pilar; Chacartegui, Ricardo; Viezzer, Eleonora; Ingeniería Energética; Física Atómica, Molecular y Nuclear
In the search for a clean and sustainable energy source for our society, fusion energy emerges as a promising candidate. The realization of a fusion power plant on Earth faces important technological and physical challenges. This thesis is a multidisciplinary project that addresses the optimization of future fusion devices from a plasma physics and engineering perspective. From the plasma physics perspective, the performance of future fusion reactors depends on the properties of the plasma, the fusion fuel. The main ion properties (in present experimental devices, deuterium) are particularly important as they determine the fusion power, which sets the electricity production. Traditionally, the main ions have been rarely diagnosed and their properties have typically been inferred from minority impurity measurements and theoretical models. In this thesis, a novel diagnostic method has been established that enables the direct experimental measurement of the main ions with a focus on the plasma edge. The plasma edge is a critical region, as it prescribes the boundary conditions for the plasma core performance, while it must enable a heat exhaust solution that limits the power loads to the plasma facing components, keeping the integrity of the fusion reactor. Plasma edge diagnostics are demanding in terms of spatial and temporal resolution, as they need to resolve fast transient events and strong spatial gradients. From an engineering perspective, the efficiency of the power conversion cycle coupled to a fusion reactor has been studied and optimized to maximize the electric power output. Cogeneration schemes as opportunities for boosting the efficiency of future fusion power plants have also been investigated. In the framework of this thesis, a new edge main ion diagnostic based on the Charge Exchange Recombination Spectroscopy technique has been installed and exploited at the ASDEX Upgrade experimental reactor, a full metal wall device, to provide main ion temperature and toroidal rotation velocity measurements. A new in-vessel optical head has been installed, which covers the outermost plasma region with a resolution down to 3 mm. A forward model, based on the collisional radiative model implemented in the fidasim code, and data analysis tools have been developed to enable an accurate interpretation of the main ion data. These are state-of-the-art measurements of edge deuterium temperature and toroidal rotation profiles in a tungsten environment, which resembles conditions relevant for future fusion reactors. Several experiments have been carried out at the ASDEX Upgrade tokamak to characterize the main ion temperature and toroidal rotation in a variety of plasma conditions. The role of plasma collisionality and heating scheme on the main ion temperature and toroidal rotation has been addressed. The main ion properties have been compared to minority impurity ion and electron measurements and serve as a testbed for theoretical transport models. In particular, the measurements are compared against neoclassical transport theory. The main ion properties in high and low confinement regimes, such as the high confinement mode (H-mode), low confinement mode (L-mode), improved energy confinement mode (I-mode) and quiescent high confinement mode (QH-mode), have been documented. It has been found that the impurity ion temperature does not always give a good description of the main ion properties, and the thermal equilibration between main and impurity ions is a complex function of heating scheme and collisionality. In H-mode, the main ion toroidal rotation is in remarkably good agreement with neoclassical theory in the steep gradient region of the plasma edge. The detailed diagnosis of the edge plasma properties is essential for understanding plasmas in present experimental devices, and consequently, for the projection towards future fusion power plants and their optimization. The integration of a portfolio of Rankine and Brayton power conversion cycles with a fusion reactor has been studied in a framework that couples the engineering equation solver and the process systems code. The fusion reactor is based on the European DEMO Baseline 2018, which sets the temperature and power boundary conditions. In the intermediate temperature range envisaged for the EU-DEMO Baseline 2018, supercritical carbon dioxide power conversion cycles constitute a very attractive technology. Nuclear fusion cogeneration of heat and electricity has been put forward as a strategy for boosting the efficiency of future fusion devices. The use of district heating networks for the recovery of low-grade heat yields efficiency improvements for all power cycle layouts. The economic viability has been studied by the definition of the levelized cost of hybrid production, which is an indicator that integrates cost estimates from process and production and distribution costs. The cogeneration scheme is feasible from an economic point of view for Rankine and supercritical carbon dioxide power cycles. This work expands potential fusion energy applications and its deployment in the energy market.

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