Investigation of Niobium Surface Roughness and Hydrogen Content with Different Polishing Conditions for Performance Recovery of Superconducting QWRs in JAEA Tokai-Tandem Accelerator

The effect of the different polishing conditions for niobium has been investigated as the basic data for polishing the superconducting quarter-wave resonators (QWRs) in the booster linac of the Tokai-tandem accelerator. Surface roughness and desorbed hydrogen amount of niobium samples with different...

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Bibliographic Details
Published in:E-journal of surface science and nanotechnology 2023/05/18, Vol.21(4), pp.344-349
Main Authors: Kamiya, Junichiro, Nii, Keisuke, Kabumoto, Hiroshi, Kondo, Yasuhiro, Tamura, Jun, Harada, Hiroyuki, Matsui, Yutaka, Matsuda, Makoto, Moriya, Katsuhiro, Ida, Yoshiaki, Ueda, Hideki
Format: Article
Language:English
Subjects:
Bubbles
Chemical polishing
Electrodes
Electropolishing
Hydrogen
Hydrogen desorption
Linear accelerators
Niobium
Superconductivity
Surface roughness
Thermal desorption spectroscopy
Thickness
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Summary:The effect of the different polishing conditions for niobium has been investigated as the basic data for polishing the superconducting quarter-wave resonators (QWRs) in the booster linac of the Tokai-tandem accelerator. Surface roughness and desorbed hydrogen amount of niobium samples with different polishing conditions such as polishing method (electropolishing: EP or chemical polishing: CP), polishing thickness, and electrode location, have been measured. For the hydrogen amount measurement, thermal desorption spectroscopy has been performed. The electrode arrangement in the EP to avoid hydrogen bubbles hitting the niobium surface is found to be important to obtain a smooth surface and less hydrogen content. The large polishing thickness resulted in a large amount of hydrogen content in the niobium or large surface roughness in the case of both EP and CP. The EP without hitting the hydrogen bubbles and with appropriate polished thickness will be the best solution for the actual polishing of the QWRs.
ISSN:1348-0391
1348-0391
DOI:10.1380/ejssnt.2023-046