Analysis of Niobium Surface and Generated Particles in Vertical Electropolishing of Single-cell Coupon Cavity
| Autor: | Chouhan, Vijay, Hayano, Hitoshi, Ida, Yoshiaki, Kato, Shigeki, Monjushiro, Hideaki, Nii, Keisuke, Saeki, Takayuki, Sawabe, Motoaki, Yamaguchi, Takanori |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| DOI: | 10.18429/jacow-srf2017-tupb092 |
| Popis: | In our previous studies, we have reported parameter investigation for vertical electropolishing (VEP) of 1-cell niobium (Nb) tesla/ILC type cavities using a Ninja cathode. A 1-cell coupon cavity containing six Nb disk coupons at its different positions was found effective to reduce time and cost to establish an optimized VEP recipe. In this work, we present surface analyses of VEPed Nb coupon surfaces using scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDX) and x-ray photoelectron spectroscopy (XPS). Surfaces contained micro- and nano-sized particles which were found with random distributions and different number densities on the beam pipe and iris coupons. Surfaces of equator coupons were found to have relatively less number of particles or almost clean. To analyze particles, a few particles were picked-up from a coupon surface using a tungsten tip under SEM and analyzed with EDX while the coupon was moved out from the SEM chamber to avoid its effect in EDX spectra. The particles were confirmed as oxygen-rich niobium and contained fluorine and carbon also. XPS analysis of the coupon surfaces was also carried out for further study of surface chemistry. Proceedings of the 18th Int. Conf. on RF Superconductivity, SRF2017, Lanzhou, China |
| Databáze: | OpenAIRE |
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