Conference Presentation

PUBDB-2022-08117

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Influence of High-Pressure Rinsing on the Oxide-Layer Thickness and Oxygen-Concentration of Niobium Samples

Ghanbari, R. (Corresponding author)Extern* ; Wenskat, M.Extern* ; Kohantorabi, M.DESY* ; Noei, H.DESY* ; Dangwal Pandey, A.DESY* ; Reschke, D.DESY* ; Hillert, W.CFEL*Extern*

2023

Abstract: This study is devoted to investigate the effect of High-Pressure Rinsing (HPR) on the outcome of annealing procedures of Niobium (Nb) superconducting radio-frequency cavities. Recently, a so-called “mid-T bake” treatment has exhibited very high-quality factors for Nb cavities. The complementary developed models assume that the quality factor severely depends on the oxygen concentration in the near-surface of niobium. On the other hand, based on our observation, we realize that HPR affects the thickness of oxide layers on the surface of niobium cavities, which is the dominant source of the oxygen diffusion during annealing. Thus, we have measured the oxide thicknesses after various HPR durations of Nb samples before and after applying mid-T bake treatment via X-ray Photoelectron Spectroscopy (XPS) and used Secondary Ion Mass Spectrometry (SIMS) to obtain the interstitial oxygen concentration after the annealing. The results of this investigation will be presented and discussed in the context of theoretical models.

Note: This work was supported by the BMBF under the research grants 05K19GUB,05H2021 and 05K22GUD

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Contributing Institute(s):

1. Supraleitende Beschleuniger Technologie (MSL)
2. Uni Hamburg / Experimentalphysik (UNI/EXP)
3. Nanolab (FS-NL)

Research Program(s):

1. 621 - Accelerator Research and Development (POF4-621) (POF4-621)

Experiment(s):

1. Superconductivity Radio Frequency Research and Development

Appears in the scientific report 2023

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