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arXiv · 2312.11940

TiO2 doping effect on reflective coating mechanical loss for gravitational wave detection at low temperature

Yukino Mori·Yota Nakayama·Kazuhiro Yamamoto·Takafumi Ushiba·Dani`ele Forest·Christophe Michel·Laurent Pinard·Julien Teillo·Gianpietro Cagnoli
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Abstract

We measured the mechanical loss of a dielectric multilayer reflective coating (ion-beam-sputtered SiO2 and Ta2O5) with and without TiO2 on sapphire disks between 6 and 77 K. The measured loss angle exhibited a temperature dependence, and the local maximum was found at approximately 20 K. This maximum was 7.0*10^(-4) (with TiO2) and 7.7*10^(-4) (without TiO2), although the previous measurement for the coating on sapphire disks showed almost no temperature dependence (Phys. Rev. D 74 022002 (2006)). We evaluated the coating thermal noise in KAGRA and discussed future investigation strategies.

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Yukino Mori, Yota Nakayama, Kazuhiro Yamamoto, Takafumi Ushiba, Dani`ele Forest, Christophe Michel, Laurent Pinard, Julien Teillo, Gianpietro Cagnoli. 2023-12-19. TiO2 doping effect on reflective coating mechanical loss for gravitational wave detection at low temperature. https://arxiv.org/abs/2312.11940

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