Hybrid Physical Chemical Vapor Deposition of Magnesium Diboride Inside 3.9 GHz Mock Cavities

Journal Article · Wed Dec 21 00:00:00 EST 2016 · IEEE Transactions on Applied Superconductivity

DOI:https://doi.org/10.1109/TASC.2016.2643567· OSTI ID:1394781

Lee, Namhoon  ^[1]; Withanage, Wenura K. ^[1]; Tan, Teng ^[1]; Wolak, Matthaeus A. ^[1]; Nassiri, Alireza ^[2]; Xi, Xiaoxing ^[1]

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1. Temple Univ., Philadelphia, PA (United States). Dept. of Physics
2. Argonne National Lab. (ANL), Argonne, IL (United States)

Magnesium diboride (MgB₂) is considered a candidate for the next generation superconducting radio frequency (SRF) cavities due to its higher critical temperature T_c (40 K) and increased superheating field (H_sh) compared to other conventional superconductors. These properties can lead to reduced BCS surface resistance (R^BCS_S) and residual resistance (R_res), according to theoretical studies, and enhanced accelerating field (E_acc) values. Here, we investigated the possibility of coating the inner surface of a 3.9 GHz SRF cavity with MgB₂ by using a hybrid physical-vapor deposition (HPCVD) system designed for this purpose. To simulate the actual 3.9 GHz SRF cavity, we also employed a stainless steel mock cavity for the study. The film qualities were characterized on small substrates that were placed at the selected positions within the cavity. MgB₂ films on stainless steel foils, niobium pieces, and SiC substrates showed transition temperatures in the range of 30-38 K with a c-axis-oriented crystallinity observed for films grown on SiC substrates. Dielectric resonator measurements at 18 GHz resulted in a quality factor of over 30 000 for the MgB₂ film grown on a SiC substrate. Furthermore, by employing the HPCVD technique, a uniform film was achieved across the cavity interior, demonstrating the feasibility of HPCVD for MgB₂ coatings for SRF cavities.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC); US Department of the Navy, Office of Naval Research (ONR)
• Grant/Contract Number: AC02-06CH11357; SC0011616; N0014-12-1-0777
• OSTI ID: 1394781
• Journal Information: IEEE Transactions on Applied Superconductivity, Vol. 27, Issue 4; ISSN 1051-8223
• Publisher: Institute of Electrical and Electronics Engineers (IEEE)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
linear particle accelerator
superconducting films
magnesium compounds
boron alloys