Persona: Sanz Pérez, Javier
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Sanz Pérez
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Javier
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Publicación New developments in the MCUNED-Plus code for radiation transport and coupled transport-activation computational simulations in accelerator-based facilities(Elsevier, 2024-06-25) López Lorente, Víctor Daniel; Sauvan, Patrick; Sanz Pérez, Javier; Ogando Serrano, Francisco M.The radiation hazard is one of the major aspects of concern in the design of a facility where it exists a risk of exposure to ionizing radiation. The nuclear analysis for radioprotection purposes requires an accurate description of the radiation fields. This is especially true in accelerator-based facilities where several types of particles are producing the radiation fields. Radiation fields exist during the accelerator operation, but delayed radiation may also be significant for a long time after operation ends. The radiation fields of concern present during the operation are due to the secondary neutrons and photons emitted by the interaction of accelerated particles with the accelerator components (beam leakage) or with the target. The radiation present after the operation is the residual photon field produced by activated materials, these materials being activated by both accelerated particles and secondary neutrons. This residual radiation field is relevant in high intensity accelerators like IFMIF-DONES. In order to address these complex radiation transport simulations, the D1SUNED code has been updated and the new code release renamed as MCUNED-Plus. The new developments include improvements in the light-ion transport like the implementation of a variance reduction for the production of secondary particles, and a new kinematics to reproduce the angular distribution of secondary particles emitted after deuteron breakup reaction. The calculation of the residual photon field in accelerator facility has also been improved by allowing to evaluate both light-ions and secondary neutrons induced shutdown dose rate in a single coupled simulation.Publicación N-acetyl-aspartate levels in the dorsolateral prefrontal cortex in the early years of schizophrenia are inversely related to disease duration.(Elsevier, 2005-03-01) Molina, Vicente; Reig Redondo, Santiago; Benito, Carlos; Pascau González-Garzón, Javier; Sarramea, Fernando; Gispert, Juan Domingo; Misiego, José M.; Palomo, Tomás; Desco, Manuel; Domínguez Sánchez, Francisco Javier; Sanz Pérez, Javier; Santa Marta Pastrana, Cristina MaríaMagnetic resonance spectroscopy studies in schizophrenia have revealed consistently reduced N-acetyl aspartate (NAA) levels in chronic patients, but not in recent-onset patients. Studies on the relationship between this marker and disease duration have commonly been negative, although it is also true that they have been conducted in patients with long-standing disease. We compared NAA levels in the dorsolateral prefrontal cortex in 16 recent-onset patients (duration: 1.8±0.6 years), 19 chronic patients (duration: 9.7±6.1 years), and 20 healthy controls. We studied the NAA/creatine and choline/creatine ratios in the dorsolateral prefrontal cortex in both hemispheres, controlling for the effect of age. Chronic patients had significantly lower NAA/Cr ratios in the left hemisphere compared to recent-onset patients and healthy controls, with no difference in Cho/Cr ratio. There were no differences between controls and recent-onset patients. There was a significant inverse relationship between left-side NAA/Cr and disease duration, suggesting that prefrontal NAA levels may progressively decrease in schizophrenia. Taken within the context of the existing literature, these results indicate that this process may be limited to the early years following the onset of the disease. Therefore, reduced prefrontal levels of NAA may be limited to chronic schizophrenia patients.Publicación GEOUNED: A new conversion tool from CAD to Monte Carlo geometry(Elsevier, 2024-05-30) Catalán Pérez, Juan Pablo; Sauvan, Patrick; García, J.; Alguacil Orejudo, Javier; Ogando Serrano, Francisco M.; Sanz Pérez, JavierThe GEOUNED code is specifically designed to convert CAD models, defined using the B-rep approach, into MC radiation transport models, defined using the CSG approach, and vice versa from MC to CAD. This code incorporates standard features commonly found in conversion tools, including decomposition, conversion, and automatic void generation. Additionally, it introduces innovative features, mainly in the automatic void generation part, which are described in this article. GEOUNED has demonstrated successful application in highly detailed 3D models used in fusion neutronics, which are known for their complex geometries, particularly those utilized in ITER. The article includes examples showcasing GEOUNED’s performance in these challenging models, as well as custom applications that highlight its flexibility in addressing non-standard problems. The code is open-source and utilizes Open CASCADE as the geometry engine, with FreeCAD serving as the Python API.Publicación A full and heterogeneous model of the ITER tokamak for comprehensive nuclear analyses(Nature Research, 2021-01-04) Juárez Mañas, Rafael; Pedroche Sánchez, Gabriel; Loughlin, M. J.; Pampin, R.; Martínez Albertos, Pablo; De Pietri, Marco; Alguacil Orejudo, Javier; Ogando Serrano, Francisco M.; Sauvan, Patrick; López Revelles, Antonio Jesús; Kolsek, Aljaz; Polunovskiy, E.; Fabbri, M.; Sanz Pérez, JavierITER is the flagship project, conceived as an experiment to select and develop the technologies for the first demonstration reactor, DEMO. Nuclear analysis is a core discipline in support of the design, commissioning and operation of the machine. To date it has been conducted with increasingly detailed partial models, which represented toroidal segments of the tokamak. However, the limitations of this methodology became evident as estimates of quantities relevant to design, safety and operation showed unquantifiable uncertainties, which is a risk. Here, we present a detailed and realistic 360° MCNP model of the ITER tokamak called E-lite. We demonstrate the model’s usability and practicality. Two examples are used to illustrate qualitatively and quantitatively how it solves previously intractable problems with marked benefits for the future nuclear analysis of ITER, with applications to DEMO and future reactors. E-lite constitutes a milestone in the field of nuclear analysis in terms of realism in the evaluation of key quantities.Publicación D1SUNED system for the determination of decay photon related quantities(Elsevier, 2019-11-18) Sauvan, Patrick; Juárez Mañas, Rafael; Pedroche Sánchez, Gabriel; Alguacil Orejudo, Javier; Catalán Pérez, Juan Pablo; Ogando Serrano, Francisco M.; Sanz Pérez, JavierThe neutron fields alter the radioactive inventory of the irradiated materials leading to subsequent decay photon fields. In some cases, these fields are of relevance either intended or undesired, normally involving safety and economics aspects. The determination of these fields can be of paramount complexity if high spatial resolution is required. The determination of these fields requires both radiation transport and activation calculations. The Direct-one-Step methodology, under the assumption that the radioactive inventory activity is lineal with the neutron flux, can address the problem with only one coupled neutron-photon transport calculation. In this paper the D1SUNED code for the calculation of decay photon field and related quantities using D1S methodology is presented. Calculation capabilities including the determination of 3D decay photon sources, filtering options, and other relevant features are presented. In terms of computational load, D1SUNED, which is based on MCNP5 code, presents improvements with respect to MCNP. It can save a 79% of the RAM memory used to store the geometry, a 98% of the loading time, and an acceleration of a factor two by controlling the decay photon emission, boosting the simulations for ITER-like problems. D1SUNED has been validated with the FNG benchmark experiment considering the null hypothesis rejection test and the C/E ratio with very positive results. As a consequence, D1SUNED has become a reference tool for the design of ITER, and other relevant nuclear fusion facilities.