Testing of a SiO2/TiO2 mirror coating on a stainless steel substrate under ITER in-port conditions

Krimmer, A.; Rosenthal, Eberhard; Andreenko, E.N.; Orlovskiy, I.I.; Allelein, H.-J.; Mertens, Ph.; Neubauer, O.

doi:10.1016/j.fusengdes.2015.06.061

Cited by 5 publications

(5 citation statements)

References 5 publications

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“…By adopting the value of Young's modulus and the expansion coefficient reported in Table 2, calculations show that the SiO 2 /TiO 2 tri-layer structure suffers a stress of ≃ −153 MPa (compressive) and ≃ +400 MPa (tensile) when the temperature drops to 50 K or rises to 700 K, respectively. Such values are not critical to induce a fatal damage, such as layer delamination or coating cracking: previous tests carried out for applications in nuclear fusion have proven that SiO 2 /TiO 2 dielectric coatings remain stable for thermal cycles up to ≃624 K tests for over 1 h. Moreover, after 85 h annealing at ≃694 K samples reveals only a slight reduction of the optical performance, mainly due to the formation of crystalline phases in the multilayer, and to some surface defects related to small local delamination 32 .…”

Section: Resultsmentioning

confidence: 99%

Multilayers for directed energy accelerated lightsails

et al. 2022

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A lightsail accelerated via directed energy is a candidate technology to send a probe into the deep space in a time period compatible with human life. The light emitted by a ground-based large-aperture phased laser array is directed onto the lightsail to produce a thrust by transferring the momentum of the incident photons. Here we demonstrate that optimized multilayer structures allow ultralight spacecraft being accelerated by laser radiation pressure up to 20% of the light velocity, and eventually even above, as long as a compromise between efficiency and weight is achieved. Layer materials are selected to provide high reflectance in the Doppler-shifted laser wavelength range as well as high emissivity in the infrared, this last characteristic being required to survive to the temperature increase during the acceleration phase.

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Section: Resultsmentioning

confidence: 99%

Multilayers for directed energy accelerated lightsails

et al. 2022

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“…Note that polarisation effects might be an issue. A report on tested mirrors can be found in [28]. A specular reflectivity of 98% can be achieved.…”

Section: The Mirror Chainmentioning

confidence: 92%

Status of the R&D activities to the design of an ITER core CXRS diagnostic system

Mertens

Bardawil

Baross

et al. 2015

Fusion Engineering and Design

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“…The harsh operating conditions inside the ITER vacuum vessel limit the list of applicable reflective materials. To date, the reflective surfaces, based on Rh, Mo, SS, as well as on thin metallic films, protected by dielectric coating [8] and multilayer dielectric coatings [9], have been investigated for the ITER in-vessel applications. The multilayer dielectric coatings show considerable efficiency, but are hardly applicable on large-scale DTS mirrors due to technological difficulties.…”

Section: Investigation Of the Reflective Surface Designmentioning

confidence: 99%

Large-scale collecting mirrors for ITER optical diagnostic

Samsonov¹,

Tereschenko²,

Mukhin³

et al. 2022

Nucl. Fusion

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The challenges of large-scale mirror design for in-vessel collection system of ITER Divertor Thomson Scattering (DTS) are under consideration. These are the mirrors located out-of-line vision of fusion plasma (so called “second mirrors” i.e. not First Mirrors) with high-reflective Ag-based coating. The paper outlines: approaches providing optical surface shape and angular position stability; Ag coating applicability in nuclear irradiation, ITER in-vessel application and its resistance to Steam Ingress. Although, this assessment and the proposed solutions are considered in terms of ITER DTS compatibility, they may also appear to be of some use in other ITER diagnostics and in diagnostics of other fusion devices.

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Testing of a SiO2/TiO2 mirror coating on a stainless steel substrate under ITER in-port conditions

Cited by 5 publications

References 5 publications

Multilayers for directed energy accelerated lightsails

Multilayers for directed energy accelerated lightsails

Status of the R&D activities to the design of an ITER core CXRS diagnostic system

Large-scale collecting mirrors for ITER optical diagnostic

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