Artículos (Física Aplicada II)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/10854

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Mechanical instability of stressed grain boundaries during plastic deformation of zirconium carbide
(Elsevier, 2016) Cano Crespo, Rafael; Moshtaghion, Bibi Malmal; Gómez García, Diego; Domínguez Rodríguez, Arturo; Retamal, Cesar; Lagos, Miguel; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física de la Materia Condensada
Grain boundaries are the elementary carriers of mechanical stress and chemical transport in polycrystalline materials. They are responsible for most macroscopic properties of them, particularly the mechanical performance. Most models take into account the ability of grain boundaries to slide each other assuming that surfaces do not suffer any deformation. However, one fact that is normally ignored is the mechanical distortion of flat boundaries under shear stresses. Indeed, such deformation is usually very small to play a significant role on the dynamics of point defects or dislocations. In this work, we will report the presence of a notably mechanical instability of flat boundaries under shear solicitation in zirconium carbide, giving rise to a periodic transversal shift. Such effect is the driving force for dislocation nucleation and annihilation, the main mechanism for high-temperature plasticity in this carbide
Carbon nanofibers replacing graphene oxide in ceramic composites as a reinforcing-phase: is it feasible?
(Elsevier, 2017) Cano Crespo, Rafael; Moshtaghion, Bibi Malmal; Gómez García, Diego; Domínguez Rodríguez, Arturo; Moreno, Rodrigo; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física de la Materia Condensada
In recent years, the interest of graphene and graphene-oxide has increased extraordinarily due to the outstanding properties concurring in this material. In ceramic science, the possibility of combining excellent electrical conductivities together with an enhancement of mechanical properties has motivated the research in fabrication of graphene oxide-reinforced ceramic composites despite the intrinsic difficulties for sintering. In this work a comparison is made between graphene oxide-reinforced alumina composites and carbon nanofiber-reinforced alumina ones. It will be concluded that the improvement of mechanical properties is scarce, if any. Since carbon nanofibers have also a good electrical conductivity their importance for future applications as a replacement of more sophisticated but expensive graphene-based ceramic composites will be stressed.
High-temperature creep of carbon nanofiber-reinforced and graphene oxide-reinforced alumina composites sintered by spark plasma sintering
(Elsevier, 2017) Cano Crespo, Rafael; Moshtaghion, Bibi Malmal; Gómez García, Diego; Domínguez Rodríguez, Arturo; Moreno, Rodrigo; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física de la Materia Condensada
Alumina (Al2O3) ceramic composites reinforced with either graphene oxide (GO) or carbon nanofibers (CNFs) were prepared using Spark Plasma Sintering. The effects of GO and CNFs on the microstructure and in consequence on their mechanical properties were investigated. The microstructure of the sintered materials have been characterized quantitatively prior to and after the creep experiments in order to discover the deformation mechanism. Graphene-oxide reinforced alumina composites were found to be more creep resistant than carbon nanofibers-reinforced alumina ones or monolithic alumina with the same grain size distribution. In all the cases, grain boundary sliding was identified as the deformation mechanism.
Graphene or carbon nanofiber-reinforced zirconia composites: are they really worthwhile for structural applications?
(Elsevier, 2018) Cano Crespo, Rafael; Moshtaghion, Bibi Malmal; Gómez García, Diego; Moreno, Rodrigo; Domínguez Rodríguez, Arturo; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física de la Materia Condensada
The use of allotropic phases of carbon (i.e. nanotubes, graphene or carbon nanofibers) as second phases to design ceramic composites is a hot topic at present. Researchers try to provide a remarkable improvement of the parent ceramic assuming that some of the outstanding mechanical properties of these phases migrate to the resultant composite. This reasonable idea has been questioned severely in the case of nanotubes addition but there is not any analysis for the other two phases cited previously. To elucidate this question, zirconia was selected as a model ceramic. This paper reports the mechanical properties of zirconia composites reinforced either with graphene or carbon nanofibers, with special emphasis on the high-temperature plasticity
3D cylindrical silicon microdosimeters: fabrication, 3 simulation and charge collection study
(IOP, 2015) Fleta Corral, María Celeste; Esteban, S.; Baselga, M.; Quirión, David; Pellegrini, M.; Guardiola, Consuelo; Cortés Giraldo, Miguel Antonio; García López, J; Jiménez Ramos, María del Carmen; Gómez, F.; Lozano, M.; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear
This paper reports on the fabrication, simulation, and charge collection characteristics of a new generation of cylindrical silicon microdosimeters fabricated on SOI wafers. The devices consist of an array of p+ electrodes surrounded by trench n+ electrodes creating well defined, cylindrical sensitive volumes. A first batch of microsensors with 5.4 μm active thickness has been successfully fabricated. The devices are fully functional with good diode behavior and a depletion voltage of only 3 V. Their charge collection characteristics have been investigated using the IBIC technique with protons and alpha particles. The IBIC maps show a 100% yield of active cells in a microdosimeter array and full charge collection efficiency in the active area of the unit microsensors. These devices constitute an step forward in the current status of microdosimeters based on silicon technologies.
Influence of bloom dynamics on Particle Export Efficiency in the North Atlantic: a comparative study of radioanalytical techniques and sediment traps
(Elsevier, 2016) Ceballos Romero, Elena; Le Moigne, Frédéric; Henson, Stephanie A.; Marsay, Chris M.; Sanders, Richard; García-Tenorio García-Balmaseda, Rafael; Villa Alfageme, María; Universidad de Sevilla. Departamento de Física Aplicada II
The Biological Carbon Pump is an important component of the global carbon cycle is (BCP). Particle Export Efficiency (PEeff), defined as the proportion of primary production (PP) exported as Particulate Organic Carbon (POC) from the surface ocean, is increasingly used as a metric of the strength of the BCP. However our knowledge of which factors drive variability of PEeff remains poor. This is partially because comparisons of PEeff in different regions often overlook the timescale over which the method used operates in relation to the phase of the plankton bloom. Here we use three techniques to estimate PEeff in situ in the North Atlantic: the radioactive pairs 238U-234Th and 210Pb-210Po, and neutrally buoyant sediment traps (PELAGRA). Order of magnitude discrepancies between values of PEeff obtained from PELAGRA relative to those obtained when applying both radionuclide techniques. POC export fluxes and satellite-derived PP suggest that this results from the differing time scales covered by the three methods and the timing of observations relative to the bloom peak. None of the three techniques are considered inappropriate to estimate PEeff in situ, but bloom dynamics must be considered in relation to the duration over which a particular sampling method operates. Our results suggest a strong seasonal variability in PEeff, most likely controlled by the community structure and hydrographic conditions. This implies that the methods used (specifically their inherent timescales) and the phase of the bloom at the time of sampling must be carefully taken into account to ensure that individual PEeff estimates compiled from different sources to construct global export algorithms are comparable
A microscopic simulation of particle flux in ocean waters: application to radioactive pair disequilibrium
(Elsevier, 2018) Soto Borrero, Feliciano Carlos de; Ceballos Romero, Elena; Villa Alfageme, María; Universidad de Sevilla. Departamento de Física Aplicada II
The biological carbon pump, a fundamental component of the global carbon cycle, is a mechanism comprised of biological processes that transfer large amounts of organic carbon from the upper ocean to the ocean’s interior. It sequesters CO2 for weeks to hundreds or even millions of years through the sinking of a complex mix of biogeo-chemical material. As particles sink the flux of particulate organic carbon attenuates and only a fraction of the flux reaches the ocean’s depth. Quantifying the attenuation of sinking particulate carbon flux is key to assess the amount of carbon sequestered in the twilight zone. Current knowledge of the particle flux attenuation relies on a reduced number of direct measurements, usually fitted to a power law, that tries to describe the result of a large variety of biological, physical and chemical processes involved. We present a stochastic simulation for particle production, sinking and degradation in the oceans that includes most of the essential ingredients to ultimately describe the sinking carbon flux in the ocean and where all the complex biogeochemical behavior is captured by macroscopic parameters. The algorithm proposed interprets these phenomena probabilistically and is an ideal framework to describe the observed patterns of particle flux attenuation in depth. Particles are randomly produced and degraded with depth-dependent functions, which reproduces the variability of these processes in nature. Hence, the simulation proposed provides a suitable approach to analyse sinking carbon when different particle sizes or speeds are used. Furthermore, production and degradation phenomena are time-dependent, this way their seasonal evolution can be additionally explored and the simulation results in an ideal test-bed for the assessment of both steady and non-steady state situations. In addition, the theoretical formulation proposed provides a simple frame to include particle-metals interactions through adsorption and desorption processes. In this paper we relate typical parametrizations of the flux attenuation curve to their corresponding degradation rate and propose an alternative parametrization to model the flux degradation function which is negligible at very large depths, therefore producing a constant residual flux, and remains finite in the euphotic zone. This degradation function is implemented in the simulation and applied to estimate the scavenging of the naturally occurring radioisotopes 234Th and 210Po. We use the results to estimate effective adsorption and desorption rate constants for both isotopes. We found that the degradation rate, rather than the half-life, controls the depth at which the parent and daughter reach equilibrium. Thus, this depth is ruled by a combination of the degradation rate and the particle sinking velocity
Influence of the Fiber Coating Type on the Strain Response of Proton-Irradiated Fiber Bragg Gratings
(IEEE, 2012) Currás, Esteban; Virto, Amparo L.; Moya, D.; Carrión, J. G.; Frovel, Malte; García López, Juan Antonio; Jiménez Ramos, María del Carmen; Palomo Pinto, Rogelio; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Universidad de Sevilla. Departamento de Ingeniería Electrónica
We report on the effect of the fiber coating on the radiation sensitivity of Fiber Bragg Gratings (FBG). For the first time this type of study has been carried out using a 13.5 MeV proton beam up to a fluence of 3.3×1015 protons/cm2 (total absorbed dose of 15 MGy). We observed a clear dependence of the radiation sensitivity on the coating, in particular, we have investigated the irradiation induced changes on the strain sensitivity; FBG strain coefficient remains stable for all the fiber within a 5%. This result demonstrates the suitability of FBGs as structural health and deformation monitors in the very hostile environment of the new generation of high-intensity particle physics proton colliders.
Numerical analysis of alpha spectra using two different codes
(Elsevier, 2008) Hurtado Bermúdez, Santiago José; Jiménez Ramos, María del Carmen; Villa Alfageme, María; Vioque Romero, Ignacio; Manjón Collado, Guillermo; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II; Junta de Andalucía; Universidad de Sevilla. RNM138: Física Nuclear Aplicada
This work presents an intercomparison between commercial software for alpha-particle spectrometry, Genie 2000, and the new free available software, Winalpha, developed by International Atomic Energy Agency (IAEA). In order to compare both codes, different environmental spectra containing plutonium, uranium, thorium and polonium have been analyzed, together with IAEA test alpha spectra. A statistical study was performed in order to evaluate the precision and accuracy in the analyses, and to enhance the confidence in using the software on alpha spectrometric studies.
Levels, distribution and bioavailability of transuranic elements released in the Palomares accident (Spain)
(Elsevier, 2008-11) Jiménez Ramos, María del Carmen; Vioque Romero, Ignacio; García-Tenorio García-Balmaseda, Rafael; García León, Manuel; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Universidad de Sevilla. RNM138: Física Nuclear Aplicada
The current levels and distribution of the remaining transuranic contamination present in the terrestrial area affected by the nuclear Palomares accident have been evaluated through the determination of the Pu-isotopes and 241Am concentrations in soils collected 35 years after the accident. In addition, after confirming that most of the contamination is present in particulate form, some bioavailability laboratory-based experiments, based on the use of single extractants, were performed as an essential step in order to study the behaviour of the Pu contamination in the soils from the affected areas.
Influence of sampling air flow rate in the decay correction applied to the determination of 7Be and short-lived radionuclides in aerosol samples
(Elsevier, 2006-12) Jiménez Ramos, María del Carmen; Manjón Collado, Guillermo; Abril Hernández, José María; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Aplicada I; Consejo de Seguridad Nuclear; Universidad de Sevilla. RNM138: Física Nuclear Aplicada
An original decay correction procedure is proposed for the activity determination of short-lived radionuclides in airborne dust samples. To this end, the hypothesis of air flow rate attenuation during sampling is considered and tested. The other decay corrections: to the delay time, from the end of the sampling until the start of the counting; and to the counting time, were executed as standard. Differences from classic corrections, which consider a constant air flux rate in the sampling with a weekly sampling duration, are of the order of 1% for 7Be and approximately 10% for 131I. Moreover, the procedure can be applied to estimate the air volume sampled in the last 24 h before the end of the sampling. This volume can be used to calculate the activity concentration of a radionuclide (short-or long-lived radionuclide) if a major nuclear accident causes an instantaneous contamination immediately before the end of sampling.
Presence of plutonium contamination in soils from Palomares (Spain)
(Elsevier, 2006) Jiménez Ramos, María del Carmen; García-Tenorio García-Balmaseda, Rafael; Vioque Romero, Ignacio; Manjón Collado, Guillermo; García León, Manuel; Universidad de Sevilla. Departamento de Física Aplicada II
More than 30 years after the occurrence of an aircraft accident which involved the detonation of two nuclear weapons in the surrounding area of the village of Palomares (Spain), the affected terrestrial area has been investigated for remaining transuranic contamination. Evidence from the presence of this contamination was initially found through the analysis of the 241Am inventories in superficial soil samples collected in the region, and was confirmed through the analysis of the 239 + 240Pu inventories and their associated 238Pu/239 + 240Pu activity ratios in the same samples. However, it was also observed that a considerable fraction of the remaining contamination in the area was present in particulate form, i.e. as “hot particles”. The work performed in our laboratory for identification, isolation and characterisation of these “hot particles” as well as some conclusions obtained from these analyses are outlined in this paper.
On the presence of enriched amounts of 235U in hot particles from the terrestrial area affected by the Palomares accident (Spain)
(Elsevier, 2007) Jiménez Ramos, María del Carmen; Barros, Haydn; García-Tenorio García-Balmaseda, Rafael; García León, Manuel; Vioque Romero, Ignacio; Manjón Collado, Guillermo; Universidad de Sevilla. Departamento de Física Aplicada II
The characterisation by ICP-MS of an isolated Pu-U hot particle originating from the nuclear weapons accident in Palomares (Spain) shows, for the first time, that its uranium content is highly enriched in 235U. The enrichment has been confirmed by independent analyses of two surface soil samples collected in a heavily contaminated area close to the impact point of one of the bombs. This finding clarifies better the composition of the weapons involved in the accident and is of importance when the inventory of U and Pu in the contaminated area are to be calculated.
Grey monazite (rare earths) mining in centre of Spain: Characterization and pre-operational radiological evaluation
(Elsevier, 2018) García-Tenorio García-Balmaseda, Rafael; Manjón Collado, Guillermo; Vioque Romero, Ignacio; Jiménez Ramos, María del Carmen; Mantero Cabrera, Juan; Díaz Francés, Inmaculada; Universidad de Sevilla. Departamento de Física Aplicada II
A radiological evaluation associated to the future mining of grey monazite nodules enriched in light rareearths, from a modest superficial deposit located in the centre of Spain, has been performed at preoperational level, and the main results are shown in this paper. Although the monazite nodules in the deposit are clearly enriched in radionuclides from the uranium and thorium series with activity concentrations higher than 1 Bq/g, the size of these nodules (in the 0.5 mme2 mm grain size interval), its refractory behaviour that prevents the leaching or dissemination of natural radionuclides to waters or other ecosystem compartments and consequently the impact in the food chain, and its presence quite diluted in the deposit at concentrations of 2.5e3 kg/m3 , conducted to conclude that pre-operationally the area to be mined for the extraction of the monazite is generating a negligible radiological impact in the public and the nearby environment. Additionally, the extraction of the raw material and the restoration of the area after mining (i.e. the mining activities which will be done in-situ, in the mining area) will be exempted of any radiological regulation attending to the European Union legislation being expected that will not generate a radiological impact.
Removal naturally occurring radionuclides from drinking water using a filter specifically designed for Drinking Water Treatment Plants
(Chemosphere, 2017) Baeza, Antonio S.; Salas García, Alejandro; Guillén, Francisco Javier; Muñoz Serrano, A.; Ontalba Salamanca, María Angeles; Jiménez Ramos, María del Carmen; Universidad de Sevilla. Departamento de Física Aplicada II
The occurrence of naturally occurring radionuclides in drinking water can pose health hazards in some populations, especially taking into account that routine procedures in Drinking Water Treatment Plants (DWTPs) are normally unable to remove them efficiently from drinking water. In fact, these procedures are practically transparent to them, and in particular to radium. In this paper, the characterization and capabilities of a patented filter designed to remove radium from drinking water with high efficiency is described. This filter is based on a sandwich structure of silica and green sand, with a natural high content manganese oxide. Both sands are authorized by Spanish authorities to be used in Drinking Water Treatment Plants. The Mn distribution in the green sand was found to be homogenous, thus providing a great number of adsorption sites for radium. Kinetic studies showed that the 226Ra adsorption on green sand was influenced by the content of major cations solved in the treated water, but the saturation level, about 96e99%, was not affected by it. The physico-chemical parameters of the treated water were unaltered by the filter. The efficiency of the filter for the removal of 226Ra remained unchanged with large water volumes passed through it, proving its potential use in DWTP. This filter was also able to remove initially the uranium content due to the presence of Fe2O3 particles in it, although it is saturated faster than radium
Measurement of plutonium isotopes, 239Pu and 240Pu, in air-filter samples from Seville (2001-2002)
(Elsevier, 2010) Chamizo Calvo, Elena; García León, Manuel; Enamorado Báez, Santiago Miguel; Jiménez Ramos, María del Carmen; Wacker, Luka; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear
Since the last nuclear atmospheric test carried out by the People Republic of China in 1980 and since the Chernobyl accident in 1986, the plutonium hasn't been directly released into the atmosphere. However, nowadays, it is still present in the troposphere. This is due to plutonium-bearing soil particles physical resuspension processes. In this work, we study for the first time the temporal variation of plutonium isotopes, 239Pu and 240Pu, baseline concentrations on a monthly basis in surface air from Seville (Spain), and their correlation with some tracers of mineral dust, during 2001 and 2002. The Pu analyses were performed by low-energy Accelerator Mass Spectrometry (AMS). The 239Pu plus 240Pu (239þ240Pu) activity levels achieved maximums during the summer period, characterized by the absence of rains, and minimums during the rainy seasons, laying in the range 1e20 nBq m3 . The 240Pu/239Pu two-year average atomic ratio was 0.18 0.03, in agreement with the fallout plutonium. A good correlation with Pu and Al and Ti levels is observed. They are crustal components usually used as tracers of African dust over European countries. The hypothesis of the influence of the Saharan dust intrusions is supported as well through the study of Total Ozone Mass Spectrometer (TOMS) daily images
Isolation of Pu-isotopes from environmental samples using ion chromatography for accelerator mass spectrometry and alpha spectrometry
(Elsevier, 2008) Chamizo Calvo, Elena; Jiménez Ramos, María del Carmen; Wacker, Lukas; Vioque Romero, Ignacio; Calleja López, Ana; García León, Manuel; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear
A radiochemical method for the isolation of plutonium-isotopes from environmental samples, based on the use of specific extraction chromatography resins for actinides (TEVA®, Eichrom Industries, Inc.), has been set up in our laboratory and optimised for their posterior determination by alpha spectrometry (AS) or accelerator mass spectrometry (AMS). The proposed radiochemical method has replaced in our lab a well-established one based on the use of a relatively un-specific anion-exchange resin (AG® 1X8, Bio-rad Laboratories, Inc.), because it is clearly less time consuming, reduces the amounts and molarities of acid wastes produced, and reproducibly gives high radiochemical yields. In order to check the reliability of the proposed radiochemical method for the determination of plutonium-isotopes in different environmental matrixes, twin aliquots of a set of samples were prepared with TEVA® and with AG® 1X8 resins and measured by AS. Some samples prepared with TEVA® resins were measured as well by AMS. As it is shown in the text, there is a comfortable agreement between AS and AMS, which adequately validates the method.
Upgrade and absolute calibration of the JET scintillator-based fast-ion loss detector
(American Institute of Physics, 2021-04) Rivero Rodríguez, Juan Francisco; Pérez Von Thun, C.; García Muñoz, Manuel; Beaumont, P.; Kiptily, V.; García López, Francisco Javier; Goloborodko, V.; Jiménez Ramos, María del Carmen; Rodríguez Ramos, Mauricio; Schoepf, K.; Yavorskij, V.; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla; Ministry of Science and Higher Education. Poland; Universidad de Sevilla. FQM402: Ciencias y Tecnologías del Plasma y el Espacio; Universidad de Sevilla. RNM138: Física Nuclear Aplicada
The JET FILD is a scintillator-based Fast-ion Loss Detector optimized to measure fusion-born alpha-particle losses. This work covers its upgrade and absolute calibration in preparation for the following JET DT experiments. A fast scintillator material (TG-Green) has been installed in the JET FILD. A heater jacket is installed around the fiber bundle, responsible for transmitting the light from the scintillator plate, to anneal the fiber obscuring due to neutron damage. The JET FILD has been upgraded with a 1 Mpx camera and 2 MHz photomultiplier data acquisition hardware. Full-orbit simulations give an estimate of the shading effects on the scintillator plate of the first wall structures and provide a synthetic signal of the JET FILD. A detector instrument function enables absolute values of fast-ion losses using calibration factors. The calibration factors are made available in a shot-to-shot basis for the characterized species and energies and with corrections for the diagnostic conditions. The fast acquisition system sets the Nyquist frequency (1 MHz) above the typical mode frequencies (≈102 kHz), thus making it possible to identify MHD-induced fast-ion losses.
IBIC analysis of SiC detectors developed for fusion applications
(Elsevier, 2020) Jiménez Ramos, María del Carmen; García López, Francisco Javier; García Osuna, Adrián; Rodríguez Ramos, Mauricio; Villalpando Barroso, A.; García Muñoz, Manuel; Andrade, Eduardo; Pellegrini, Giulio; Otero Ugobono, Sofía; Godignon, Philippe; Rafí, Joan Marc; Rius, Gemma; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear
In this work, we consider a 4H-SiC detector as a plasma diagnostic system for the detection of fusion-born alpha particles in future nuclear fusion reactors. A nuclear microprobe was used to locally irradiate micrometer-sized regions of the detector with 3.5 MeV He ions to fluences from 5 × 109 to 5 × 1011 cm-2. Ion Beam Induced Charge (IBIC) microscopy was employed to study its degradation in Charge Collection Efficiency (CCE) and energy resolution after irradiation. At high reverse-bias voltages, both parameters remain practically unaffected for fluences up to 1 × 1011 cm-2, while a significant deterioration of the spectroscopic performance was observed above 3 × 1011 cm-2. A theoretical drift-diffusion model, in combination with Shockley-Read-Hall recombination statistics, was used to obtain the holes lifetime from the fitting of the experimental CCE values measured at different reverse voltages. Holes lifetime was found to strongly decrease with increasing particle fluence, changing from 57 ns in pristine detectors to 0.2 ns after irradiation with a fluence of 1 × 1011 cm-2.
Characterization of scintillator materials for Fast-Ion Loss detectors in nuclear fusion reactors
(Elsevier, 2014-08-01) Jiménez Ramos, María del Carmen; García López, Francisco Javier; García Muñoz, Manuel; Rodríguez Ramos, Mauricio; Carmona Gázquez, M; Zurro, B.; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear
In fusion plasma reactors, fast ion generated by heating systems and fusion born particles must be well confined. The presence of magnetohydrodynamic (MHD) instabilities can lead to a significant loss of these ions, which may reduce drastically the heating efficiency and may cause damage to plasma facing components in the vacuum vessel. In order to understand the physics underlying the fast ion loss mechanism, scintillator based detectors have been installed in several fusion devices. In this work we present the absolute photon yield and its degradation with ion fluence in terms of the number of photons emitted per incident ion of several scintillators thin coatings: SrGa2S4:Eu2+ (TG-Green), Y3Al5O12:Ce3+ (P46) and Y2O3:Eu3+ (P56) when irradiated with light ions of different masses (deuterium ions, protons and α-particles) at energies between approximately 575 keV and 3 MeV. The photon yield will be discussed in terms of the energy deposited by the particles into the scintillator. For that, the actual composition and thickness of the thin layers were determined by Rutherford Backscattering Spectrometry (RBS).

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