Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors

Iwano, Keisuke; Yamanoi, Kohei; Iwasa, Yuki; Mori, Kazuyuki; Minami, Yuki; Arita, Ren; Yamanaka, Takuma; Fukuda, Kazuhito; Empizo, Melvin John F.; Takano, Keisuke; Shimizu, Toshihiko; Nakajima, Makoto; Yoshimura, Masashi; Sarukura, Nobuhiko; Norimatsu, Takayoshi; Hangyo, Masanori; Azechi, Hiroshi; Singidas, Bess G.; Sarmago, Roland V.; Oya, Makoto; Ueda, Yoshio

doi:https://doi.org/10.1063/1.4965927

Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors

Iwano, Keisuke; Yamanoi, Kohei; Iwasa, Yuki et al.

AIP Advances, 2016, 6(10), 105108

Number of Access:2,688（2025-07-24 07:26 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/92545

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Title	Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors
Creator	CreatorName Iwano, Keisuke
	NRID 1000030722813 1000030722813 ORCID 0000-0003-4492-4099 0000-0003-4492-4099 researchmap permalink yamanoi-k yamanoi-k Scopus Author ID 35243839300 35243839300 CreatorName Yamanoi, Kohei
	NRID 1000090838947 1000090838947 CreatorName Iwasa, Yuki
	CreatorName Mori, Kazuyuki
	CreatorName Minami, Yuki
	CreatorName Arita, Ren
	CreatorName Yamanaka, Takuma
	CreatorName Fukuda, Kazuhito
	CreatorName Empizo, Melvin John F.
	NRID 1000070583102 1000070583102 CreatorName Takano, Keisuke
	NRID 1000080415182 1000080415182 researchmap permalink shimizu-tshk shimizu-tshk Scopus Author ID 35446354400 35446354400 CreatorName Shimizu, Toshihiko
	NRID 1000040361662 1000040361662 ORCID 0000-0002-0351-2197 0000-0002-0351-2197 researchmap permalink nakajimamakoto nakajimamakoto Scopus Author ID 55236697600 55236697600 CreatorName Nakajima, Makoto
	NRID 1000060314382 1000060314382 researchmap permalink read0191199 read0191199 Scopus Author ID 7403136552 7403136552 ORCID 0000-0002-0770-1251 0000-0002-0770-1251 CreatorName Yoshimura, Masashi
	NRID 1000040260202 1000040260202 researchmap permalink read0051054 read0051054 Scopus Author ID 56251140500 56251140500 CreatorName Sarukura, Nobuhiko
	NRID 1000050135753 1000050135753 researchmap permalink read0014477 read0014477 CreatorName Norimatsu, Takayoshi
	NRID 1000010144429 1000010144429 CreatorName Hangyo, Masanori
	NRID 1000090135666 1000090135666 researchmap permalink read0014474 read0014474 CreatorName Azechi, Hiroshi
	CreatorName Singidas, Bess G.
	CreatorName Sarmago, Roland V.
	NRID 1000010804750 1000010804750 CreatorName Oya, Makoto
	NRID 1000030193816 1000030193816 researchmap permalink read0014152 read0014152 Scopus Author ID 7403978278 7403978278 CreatorName Ueda, Yoshio
Description	Iwano K., Yamanoi K., Iwasa Y., et al. Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors. AIP Advances 6, 105108 (2016); https://doi.org/10.1063/1.4965927.
Abstract	We investigate the optical transmittances of ion-irradiated sapphire crystals as potential vacuum ultraviolet (VUV) to near-infrared (NIR) window materials of fusion reactors. Under potential conditions in fusion reactors, sapphire crystals are irradiated with hydrogen (H), deuterium (D), and helium (He) ions with 1-keV energy and ∼ 1020-m-2 s-1 flux. Ion irradiation decreases the transmittances from 140 to 260 nm but hardly affects the transmittances from 300 to 1500 nm. H-ion and D-ion irradiation causes optical absorptions near 210 and 260 nm associated with an F-center and an F+-center, respectively. These F-type centers are classified as Schottky defects that can be removed through annealing above 1000 K. In contrast, He-ion irradiation does not cause optical absorptions above 200 nm because He-ions cannot be incorporated in the crystal lattice due to the large ionic radius of He-ions. Moreover, the significant decrease in transmittance of the ion-irradiated sapphire crystals from 140 to 180 nm is related to the light scattering on the crystal surface. Similar to diamond polishing, ion irradiation modifies the crystal surface thereby affecting the optical properties especially at shorter wavelengths. Although the transmittances in the VUV wavelengths decrease after ion irradiation, the transmittances can be improved through annealing above 1000 K. With an optical transmittance in the VUV region that can recover through simple annealing and with a high transparency from the ultraviolet (UV) to the NIR region, sapphire crystals can therefore be used as good optical windows inside modern fusion power reactors in terms of light particle loadings of hydrogen isotopes and helium.
Publisher	American Institute of Physics Inc.subs@aip.org
Source Title	AIP Advances
Volume (Issue)	6(10)
Page	105108
Date of Issued	2016-10-17
Language	English
Handle URL	https://hdl.handle.net/11094/92545
eISSN	21583226
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1063/1.4965927
Access Rights	open access
CopyRight	This article is licensed under a Creative Commons Attribution 4.0 International License.
oaire:version	Version of Record
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCMI Type	Text
DCTERMS.bibliographicCitation	AIP Advances. 2016, 6(10), p. 105108
DC.title	Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors
DC.creator	Iwano, Keisuke
	Yamanoi, Kohei
	Iwasa, Yuki
	Mori, Kazuyuki
	Minami, Yuki
	Arita, Ren
	Yamanaka, Takuma
	Fukuda, Kazuhito
	Empizo, Melvin John F.
	Takano, Keisuke
	Shimizu, Toshihiko
	Nakajima, Makoto
	Yoshimura, Masashi
	Sarukura, Nobuhiko
	Norimatsu, Takayoshi
	Hangyo, Masanori
	Azechi, Hiroshi
	Singidas, Bess G.
	Sarmago, Roland V.
	Oya, Makoto
	Ueda, Yoshio
DC.publisher	American Institute of Physics Inc.subs@aip.org
DC.language' scheme='DCTERMS.RFC1766	English
DC.type' scheme='DCTERMS.DCMIType	Text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2016-10-17
DC.identifier	https://doi.org/10.1063/1.4965927
DC.description	Iwano K., Yamanoi K., Iwasa Y., et al. Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors. AIP Advances 6, 105108 (2016); https://doi.org/10.1063/1.4965927.
DCTERMS.abstract	We investigate the optical transmittances of ion-irradiated sapphire crystals as potential vacuum ultraviolet (VUV) to near-infrared (NIR) window materials of fusion reactors. Under potential conditions in fusion reactors, sapphire crystals are irradiated with hydrogen (H), deuterium (D), and helium (He) ions with 1-keV energy and ∼ 1020-m-2 s-1 flux. Ion irradiation decreases the transmittances from 140 to 260 nm but hardly affects the transmittances from 300 to 1500 nm. H-ion and D-ion irradiation causes optical absorptions near 210 and 260 nm associated with an F-center and an F+-center, respectively. These F-type centers are classified as Schottky defects that can be removed through annealing above 1000 K. In contrast, He-ion irradiation does not cause optical absorptions above 200 nm because He-ions cannot be incorporated in the crystal lattice due to the large ionic radius of He-ions. Moreover, the significant decrease in transmittance of the ion-irradiated sapphire crystals from 140 to 180 nm is related to the light scattering on the crystal surface. Similar to diamond polishing, ion irradiation modifies the crystal surface thereby affecting the optical properties especially at shorter wavelengths. Although the transmittances in the VUV wavelengths decrease after ion irradiation, the transmittances can be improved through annealing above 1000 K. With an optical transmittance in the VUV region that can recover through simple annealing and with a high transparency from the ultraviolet (UV) to the NIR region, sapphire crystals can therefore be used as good optical windows inside modern fusion power reactors in terms of light particle loadings of hydrogen isotopes and helium.
DC.rights	This article is licensed under a Creative Commons Attribution 4.0 International License.
DC.format	92545
citation_title	Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors
citation_author	Iwano, Keisuke
	Yamanoi, Kohei
	Iwasa, Yuki
	Mori, Kazuyuki
	Minami, Yuki
	Arita, Ren
	Yamanaka, Takuma
	Fukuda, Kazuhito
	Empizo, Melvin John F.
	Takano, Keisuke
	Shimizu, Toshihiko
	Nakajima, Makoto
	Yoshimura, Masashi
	Sarukura, Nobuhiko
	Norimatsu, Takayoshi
	Hangyo, Masanori
	Azechi, Hiroshi
	Singidas, Bess G.
	Sarmago, Roland V.
	Oya, Makoto
	Ueda, Yoshio
citation_publisher	American Institute of Physics Inc.subs@aip.org
citation_language	English
citation_date	2016-10-17
citation_journal_title	AIP Advances
citation_volume	6
citation_issue	10
citation_firstpage	105108
citation_doi	https://doi.org/10.1063/1.4965927
citation_public_url	https://hdl.handle.net/11094/92545

Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors

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