Dataset Information

Development and characterization of Nb₃Sn/Al₂O₃ superconducting multilayers for particle accelerators.

ABSTRACT: Superconducting radio-frequency (SRF) resonator cavities provide extremely high quality factors > 10¹⁰ at 1-2 GHz and 2 K in large linear accelerators of high-energy particles. The maximum accelerating field of SRF cavities is limited by penetration of vortices into the superconductor. Present state-of-the-art Nb cavities can withstand up to 50 MV/m accelerating gradients and magnetic fields of 200-240 mT which destroy the low-dissipative Meissner state. Achieving higher accelerating gradients requires superconductors with higher thermodynamic critical fields, of which Nb₃Sn has emerged as a leading material for the next generation accelerators. To overcome the problem of low vortex penetration field in Nb₃Sn, it has been proposed to coat Nb cavities with thin film Nb₃Sn multilayers with dielectric interlayers. Here, we report the growth and multi-technique characterization of stoichiometric Nb₃Sn/Al₂O₃ multilayers with good superconducting and RF properties. We developed an adsorption-controlled growth process by co-sputtering Nb and Sn at high temperatures with a high overpressure of Sn. The cross-sectional scanning electron transmission microscope images show no interdiffusion between Al₂O₃ and Nb₃Sn. Low-field RF measurements suggest that our multilayers have quality factor comparable with cavity-grade Nb at 4.2 K. These results provide a materials platform for the development and optimization of high-performance SIS multilayers which could overcome the intrinsic limits of the Nb cavity technology.

SUBMITTER: Sundahl C

PROVIDER: S-EPMC8032729 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Coating system(s) will be required for Nb-silicide based alloys. Alumina forming alloys that are chemically compatible with the Nb-silicide based alloy substrate could be components of such systems. The intermetallic alloys Nb1.45Si2.7Ti2.25Al3.25Hf0.35 (MG5) and Nb1.35Si2.3Ti2.3Al3.7Hf0.35 (MG6) were studied in the cast, heat treated and isothermally oxidised conditions at 800 and 1200 °C to find out if they are αAl₂O₃ scale formers. A (Al/Si)alloy versus Nb/(Ti + Hf)alloy map, which can be considered to be a map for Multi-Principle Element or Complex Concentrated Nb-Ti-Si-Al-Hf alloys, and a [Nb/(Ti + Hf)]Nb5Si3 versus [Nb/(Ti + Hf)]alloy map were constructed making use of the alloy design methodology NICE and data from a previously studied alloy, and were used to select the alloys MG5 and MG6 that were expected (i) not to pest, (ii) to form αAl₂O₃ scale at 1200 °C, (iii) to have no solid solution, (iv) to form only hexagonal Nb₅Si₃ and (v) to have microstructures consisting of hexagonal Nb₅Si₃, Ti₅Si₃, Ti₅Si₄, TiSi silicides, and tri-aluminides and Al rich TiAl. Both alloys met the requirements (i) to (v). The alumina scale was able to self-heal at 1200 °C. Liquation in the alloy MG6 at 1200 °C was linked with the formation of a eutectic like structure and the TiAl aluminide in the cast alloy. Key to the oxidation of the alloys was the formation (i) of "composite" silicide grains in which the Nb₅Si₃ core was surrounded by the Ti₅Si₄ and TiSi silicides, and (ii) of tri-aluminides with high Al/Si ratio, particularly at 1200 °C and very low Nb/Ti ratio forming in-between the "composite" silicide grains. Both alloys met the "standard definition" of high entropy alloys (HEAs). Compared with HEAs with bcc solid solution and intermetallics, the VEC values of both the alloys were outside the range of reported values. The parameters VEC,  and  of Nb-Ti-Si-Al-Hf coating alloys and non-pesting Nb-silicide based alloys were compared and trends were established. Selection of coating alloys with possible "layered" structures was discussed and alloy compositions were proposed.

Dataset Information

Development and characterization of Nb₃Sn/Al₂O₃ superconducting multilayers for particle accelerators.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Development and characterization of Nb3Sn/Al2O3 superconducting multilayers for particle accelerators.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Development and characterization of Nb₃Sn/Al₂O₃ superconducting multilayers for particle accelerators.