Ponente
Descripción
Scintillator-based diagnostics, such as Fast Ion Loss Detectors (FILD) [1] and Ion-Neutral Particle Analyzers (INPA) [2], play a crucial role in characterizing energetic particle behavior in magnetic confinement fusion devices. These diagnostics rely on visible light emission induced by energetic ion irradiation (ionoluminescence). A common assumption in theses diagnostics is that light emission is isotropic [3]; however, this has not been experimentally validated for materials of interest in fusion research. In this work, we present a study of the angular dependence of light emission in two scintillator materials used in fusion diagnostics: TG-Green (SrGa₂S₄:Eu²⁺) and β-SiAlON (SiAlON). Experiments were conducted at the 3 MV Tandem accelerator of the Centro Nacional de Aceleradores (CNA, Seville), where samples were irradiated with 3.5 MeV He beams, an energy relevant to fusion applications. Light emission was collected through an optical fiber mounted on a rotating stage, with the other end coupled to an optical spectrometer. This configuration allowed measurements at different observation angles with respect to the ion beam axis. Prior to the angular measurements, we evaluated two potential sources of systematic error: the bending induced transmission loss in the optical fiber and the ion beam induced degradation of the scintillator. This ensured that any observed variation in light intensity with angle could be confidently attributed to the emission anisotropy rather than to optical fiber bending or progressive damage to the scintillator material. Preliminary results indicate measurable variations in emission intensity with observation angle, suggesting that the isotropic emission assumption may require revision. Furthermore, both scintillators exhibited gradual degradation in light output under sustained ion exposure, with material-dependent resilience. These findings have direct implications for the calibration and interpretation of scintillator-based diagnostics in current devices and for the design of future systems for ITER and other next-generation fusion reactors.
(1) García-Muñoz, M.; Kocan, M.; Ayllon-Guerola, J.; Bertalot, L.; Bonnet, Y.; Casal, N.; Galdon, J.; García López, J.; Giacomin, T.; González-Martín, J.; Gunn, J. P.; Jiménez-Ramos, M. C.; Kiptily, V.; Pinches, S. D.; Rodríguez-Ramos, M.; Reichle, R.; Rivero-Rodríguez, J. F.; Sanchis-Sánchez, L.; Snicker, A.; Vayakis, G.; Veshchev, E.; Vorpahl, Ch.; Walsh, M.; Walton, R. Rev. Sci. Instrum. 2016, 87, 11D829.
(2) J. Rueda-Rueda, M. Garcia-Munoz, E. Viezzer, P. A. Schneider, J.Garcia-Dominguez, J. Ayllon-Guerola, J. Galdon-Quiroga, A. Herrmann, X. Du, M. A. Van Zeeland, P. Oyola, M. Rodriguez-Ramos, the ASDEX-Upgrade team.. Rev. Sci. Instrum. 2021, 92, 043554.
(3) M Rodriguez-Ramos, M Garcia-Munoz, M C Jimenez-Ramos, J Garcia Lopez, J Galdon-Quiroga, L Sanchis-Sanchez, J Ayllon-Guerola, M Faitsch, J Gonzalez-Martin, A Hermann, P de Marne, J F Rivero-Rodriguez, B Sieglin, A Snicker and the ASDEX Upgrade Team. Plasma Phys. Control. Fusion. 2017, 59, 105009.
Abstract
Scintillator-based diagnostics, such as Fast Ion Loss Detectors (FILD) [1] and Ion-Neutral Particle Analyzers (INPA) [2], play a crucial role in characterizing energetic particle behavior in magnetic confinement fusion devices. These diagnostics rely on visible light emission induced by energetic ion irradiation (ionoluminescence). A common assumption in theses diagnostics is that light emission is isotropic [3]; however, this has not been experimentally validated for materials of interest in fusion research. In this work, we present a study of the angular dependence of light emission in two scintillator materials used in fusion diagnostics: TG-Green (SrGa₂S₄:Eu²⁺) and β-SiAlON (SiAlON). Experiments were conducted at the 3 MV Tandem accelerator of the Centro Nacional de Aceleradores (CNA, Seville), where samples were irradiated with 3.5 MeV He beams, an energy relevant to fusion applications. Light emission was collected through an optical fiber mounted on a rotating stage, with the other end coupled to an optical spectrometer. This configuration allowed measurements at different observation angles with respect to the ion beam axis. Prior to the angular measurements, we evaluated two potential sources of systematic error: the bending induced transmission loss in the optical fiber and the ion beam induced degradation of the scintillator. This ensured that any observed variation in light intensity with angle could be confidently attributed to the emission anisotropy rather than to optical fiber bending or progressive damage to the scintillator material. Preliminary results indicate measurable variations in emission intensity with observation angle, suggesting that the isotropic emission assumption may require revision. Furthermore, both scintillators exhibited gradual degradation in light output under sustained ion exposure, with material-dependent resilience. These findings have direct implications for the calibration and interpretation of scintillator-based diagnostics in current devices and for the design of future systems for ITER and other next-generation fusion reactors.
(1) García-Muñoz, M.; Kocan, M.; Ayllon-Guerola, J.; Bertalot, L.; Bonnet, Y.; Casal, N.; Galdon, J.; García López, J.; Giacomin, T.; González-Martín, J.; Gunn, J. P.; Jiménez-Ramos, M. C.; Kiptily, V.; Pinches, S. D.; Rodríguez-Ramos, M.; Reichle, R.; Rivero-Rodríguez, J. F.; Sanchis-Sánchez, L.; Snicker, A.; Vayakis, G.; Veshchev, E.; Vorpahl, Ch.; Walsh, M.; Walton, R. Rev. Sci. Instrum. 2016, 87, 11D829.
(2) J. Rueda-Rueda, M. Garcia-Munoz, E. Viezzer, P. A. Schneider, J.Garcia-Dominguez, J. Ayllon-Guerola, J. Galdon-Quiroga, A. Herrmann, X. Du, M. A. Van Zeeland, P. Oyola, M. Rodriguez-Ramos, the ASDEX-Upgrade team.. Rev. Sci. Instrum. 2021, 92, 043554.
(3) M Rodriguez-Ramos, M Garcia-Munoz, M C Jimenez-Ramos, J Garcia Lopez, J Galdon-Quiroga, L Sanchis-Sanchez, J Ayllon-Guerola, M Faitsch, J Gonzalez-Martin, A Hermann, P de Marne, J F Rivero-Rodriguez, B Sieglin, A Snicker and the ASDEX Upgrade Team. Plasma Phys. Control. Fusion. 2017, 59, 105009.
