Radiation effects in optical coatings for ITER diagnostics

Augusto Pereira; M. Medrano; E. Leon-Gutierrez; Carmen Pastor; Fernando Mota; Rafael Vila; Carmen Rodriguez; Ricardo Carrasco; Fernando Lapayese; Angel de la Peña; Alfonso Soleto; Esther Rincón; S. Cabrera; Vincente M. Queral; Alberto Fernández; Raquel López-Heredero; C. Torquemada; Tuesta Rodrigo; José Luis  González Gómez; T. Belenguer; Ludo Vermeeren; Willem Leysen; Juan José Piqueras; Frédéric Le-Guern; Cristina Alén-Cordero

doi:10.1016/j.fusengdes.2023.113438

Radiation effects in optical coatings for ITER diagnostics

Augusto Pereira, M. Medrano, E. Leon-Gutierrez, Carmen Pastor, Fernando Mota, Rafael Vila, Carmen Rodriguez, Ricardo Carrasco, Fernando Lapayese, Angel de la Peña, Alfonso Soleto, Esther Rincón, S. Cabrera, Vincente M. Queral, Alberto Fernández, Raquel López-Heredero, C. Torquemada, Tuesta Rodrigo, José Luis González Gómez, T. BelenguerLudo Vermeeren, Willem Leysen, Juan José Piqueras, Frédéric Le-Guern, Cristina Alén-Cordero

Research output › peer-review

Abstract

The aim is to provide an assessment of radiation damage in coated films on refractive substrates that could be used as relevant information to protect the field lenses in optical diagnostics for ITER. Radiation-resistant optical materials with transparent properties should transfer light from plasma to detectors through the interspace until the port cell area where they are located (more than 10 m from the vacuum window). These optical coatings and substrates should have resilience enough to withstand neutron and gamma irradiation without significant degradation of their transmittance. Coated sapphire (Al2O3 windows), YAG with Broad Band Anti-Reflective (BBAR) and substrates of BaF2/CaF2 protected with anti-humidity coating (Parylene-C) were extensively tested. After testing, transmission measurements and analysis of optical surfaces yield significant discoveries. All substrates showed good refractive performance under gamma radiation. On the contrary, Parylene-C did not resist temperatures above 100 degrees Celsius as expected, according to manufacturing specifications. In addition, it was observed that with an energy dose of 332 kGy of gamma rays and a significantly lower temperature of 50 degrees Celsius, the Parylene-C protection is also damaged. Coated sapphire had the best overall performance with respect to the neutron irradiation tests. Nevertheless, the decrease in transmission observed in the YAG and BaF2 coated samples is not significant for the expected cumulative neutron dose that these samples will receive at their location within the diagnostic. This information was considered for the selection of the best candidates as refractive lenses and optical coatings for the Preliminary Design Review (PDR) of ex-vessel components that will integrate the Wide-Angle Viewing System (WAVS) for ITER Equatorial Port 12. © 2023 Elsevier B.V.

Original language	English
Article number	113438
Number of pages	7
Journal	fusion engineering and design
Volume	188
DOIs	https://doi.org/10.1016/j.fusengdes.2023.113438
State	Published - Mar 2023

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10.1016/j.fusengdes.2023.113438

Cite this

Pereira, A., Medrano, M., Leon-Gutierrez, E., Pastor, C., Mota, F., Vila, R., Rodriguez, C., Carrasco, R., Lapayese, F., de la Peña, A., Soleto, A., Rincón, E., Cabrera, S., Queral, V. M., Fernández, A., López-Heredero, R., Torquemada, C., Rodrigo, T., González Gómez, J. L., ... Alén-Cordero, C. (2023). Radiation effects in optical coatings for ITER diagnostics. fusion engineering and design, 188, Article 113438. https://doi.org/10.1016/j.fusengdes.2023.113438

@article{bbc2d4d7e4b5404dae9d381c7981b80e,

title = "Radiation effects in optical coatings for ITER diagnostics",

abstract = "The aim is to provide an assessment of radiation damage in coated films on refractive substrates that could be used as relevant information to protect the field lenses in optical diagnostics for ITER. Radiation-resistant optical materials with transparent properties should transfer light from plasma to detectors through the interspace until the port cell area where they are located (more than 10 m from the vacuum window). These optical coatings and substrates should have resilience enough to withstand neutron and gamma irradiation without significant degradation of their transmittance. Coated sapphire (Al2O3 windows), YAG with Broad Band Anti-Reflective (BBAR) and substrates of BaF2/CaF2 protected with anti-humidity coating (Parylene-C) were extensively tested. After testing, transmission measurements and analysis of optical surfaces yield significant discoveries. All substrates showed good refractive performance under gamma radiation. On the contrary, Parylene-C did not resist temperatures above 100 degrees Celsius as expected, according to manufacturing specifications. In addition, it was observed that with an energy dose of 332 kGy of gamma rays and a significantly lower temperature of 50 degrees Celsius, the Parylene-C protection is also damaged. Coated sapphire had the best overall performance with respect to the neutron irradiation tests. Nevertheless, the decrease in transmission observed in the YAG and BaF2 coated samples is not significant for the expected cumulative neutron dose that these samples will receive at their location within the diagnostic. This information was considered for the selection of the best candidates as refractive lenses and optical coatings for the Preliminary Design Review (PDR) of ex-vessel components that will integrate the Wide-Angle Viewing System (WAVS) for ITER Equatorial Port 12. {\textcopyright} 2023 Elsevier B.V.",

keywords = "Radiation-resistant, Field lens, Optical coating, Parylene-C, Sapphire, YAG, BaF2",

author = "Augusto Pereira and M. Medrano and E. Leon-Gutierrez and Carmen Pastor and Fernando Mota and Rafael Vila and Carmen Rodriguez and Ricardo Carrasco and Fernando Lapayese and {de la Pe{\~n}a}, Angel and Alfonso Soleto and Esther Rinc{\'o}n and S. Cabrera and Queral, {Vincente M.} and Alberto Fern{\'a}ndez and Raquel L{\'o}pez-Heredero and C. Torquemada and Tuesta Rodrigo and {Gonz{\'a}lez G{\'o}mez}, {Jos{\'e} Luis} and T. Belenguer and Ludo Vermeeren and Willem Leysen and Piqueras, {Juan Jos{\'e}} and Fr{\'e}d{\'e}ric Le-Guern and Cristina Al{\'e}n-Cordero",

note = "Score=10",

year = "2023",

month = mar,

doi = "10.1016/j.fusengdes.2023.113438",

language = "English",

volume = "188",

journal = "fusion engineering and design",

issn = "0920-3796",

publisher = "Elsevier B.V.",

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Pereira, A, Medrano, M, Leon-Gutierrez, E, Pastor, C, Mota, F, Vila, R, Rodriguez, C, Carrasco, R, Lapayese, F, de la Peña, A, Soleto, A, Rincón, E, Cabrera, S, Queral, VM, Fernández, A, López-Heredero, R, Torquemada, C, Rodrigo, T, González Gómez, JL, Belenguer, T, Vermeeren, L , Leysen, W, Piqueras, JJ, Le-Guern, F & Alén-Cordero, C 2023, 'Radiation effects in optical coatings for ITER diagnostics', fusion engineering and design, vol. 188, 113438. https://doi.org/10.1016/j.fusengdes.2023.113438

TY - JOUR

T1 - Radiation effects in optical coatings for ITER diagnostics

AU - Pereira, Augusto

AU - Medrano, M.

AU - Leon-Gutierrez, E.

AU - Pastor, Carmen

AU - Mota, Fernando

AU - Vila, Rafael

AU - Rodriguez, Carmen

AU - Carrasco, Ricardo

AU - Lapayese, Fernando

AU - de la Peña, Angel

AU - Soleto, Alfonso

AU - Rincón, Esther

AU - Cabrera, S.

AU - Queral, Vincente M.

AU - Fernández, Alberto

AU - López-Heredero, Raquel

AU - Torquemada, C.

AU - Rodrigo, Tuesta

AU - González Gómez, José Luis

AU - Belenguer, T.

AU - Vermeeren, Ludo

AU - Leysen, Willem

AU - Piqueras, Juan José

AU - Le-Guern, Frédéric

AU - Alén-Cordero, Cristina

N1 - Score=10

PY - 2023/3

Y1 - 2023/3

N2 - The aim is to provide an assessment of radiation damage in coated films on refractive substrates that could be used as relevant information to protect the field lenses in optical diagnostics for ITER. Radiation-resistant optical materials with transparent properties should transfer light from plasma to detectors through the interspace until the port cell area where they are located (more than 10 m from the vacuum window). These optical coatings and substrates should have resilience enough to withstand neutron and gamma irradiation without significant degradation of their transmittance. Coated sapphire (Al2O3 windows), YAG with Broad Band Anti-Reflective (BBAR) and substrates of BaF2/CaF2 protected with anti-humidity coating (Parylene-C) were extensively tested. After testing, transmission measurements and analysis of optical surfaces yield significant discoveries. All substrates showed good refractive performance under gamma radiation. On the contrary, Parylene-C did not resist temperatures above 100 degrees Celsius as expected, according to manufacturing specifications. In addition, it was observed that with an energy dose of 332 kGy of gamma rays and a significantly lower temperature of 50 degrees Celsius, the Parylene-C protection is also damaged. Coated sapphire had the best overall performance with respect to the neutron irradiation tests. Nevertheless, the decrease in transmission observed in the YAG and BaF2 coated samples is not significant for the expected cumulative neutron dose that these samples will receive at their location within the diagnostic. This information was considered for the selection of the best candidates as refractive lenses and optical coatings for the Preliminary Design Review (PDR) of ex-vessel components that will integrate the Wide-Angle Viewing System (WAVS) for ITER Equatorial Port 12. © 2023 Elsevier B.V.

AB - The aim is to provide an assessment of radiation damage in coated films on refractive substrates that could be used as relevant information to protect the field lenses in optical diagnostics for ITER. Radiation-resistant optical materials with transparent properties should transfer light from plasma to detectors through the interspace until the port cell area where they are located (more than 10 m from the vacuum window). These optical coatings and substrates should have resilience enough to withstand neutron and gamma irradiation without significant degradation of their transmittance. Coated sapphire (Al2O3 windows), YAG with Broad Band Anti-Reflective (BBAR) and substrates of BaF2/CaF2 protected with anti-humidity coating (Parylene-C) were extensively tested. After testing, transmission measurements and analysis of optical surfaces yield significant discoveries. All substrates showed good refractive performance under gamma radiation. On the contrary, Parylene-C did not resist temperatures above 100 degrees Celsius as expected, according to manufacturing specifications. In addition, it was observed that with an energy dose of 332 kGy of gamma rays and a significantly lower temperature of 50 degrees Celsius, the Parylene-C protection is also damaged. Coated sapphire had the best overall performance with respect to the neutron irradiation tests. Nevertheless, the decrease in transmission observed in the YAG and BaF2 coated samples is not significant for the expected cumulative neutron dose that these samples will receive at their location within the diagnostic. This information was considered for the selection of the best candidates as refractive lenses and optical coatings for the Preliminary Design Review (PDR) of ex-vessel components that will integrate the Wide-Angle Viewing System (WAVS) for ITER Equatorial Port 12. © 2023 Elsevier B.V.

KW - Radiation-resistant

KW - Field lens

KW - Optical coating

KW - Parylene-C

KW - Sapphire

KW - YAG

KW - BaF2

U2 - 10.1016/j.fusengdes.2023.113438

DO - 10.1016/j.fusengdes.2023.113438

M3 - Article

SN - 0920-3796

VL - 188

JO - fusion engineering and design

JF - fusion engineering and design

M1 - 113438

ER -