PRELIMINARY RESULTS ON "POLARIZED" BUFFERED CHEMICAL POLISHING OF A LARGE GRAIN NIOBIUM CAVITY
In order to further understand the relation between the high-field Q-drop and the native oxide layer on the surface of SRF niobium cavities, we tried to alter the oxidation of niobium by applying a small voltage between a large-grain niobium cavity and a niobium rod inserted in the center, during buffered chemical polishing (BCP). The cavity RF test results at 1.7 K and 2.0 K did not show any major difference in the Q-drop behavior, compared to a standard BCP treatment. In one case, dark gray regions were visible inside the cavity and were responsible for additional losses, as seen with temperature maps. In order to better understand the electrochemical process occurring during the "polarized" BCP treatment, measurements of the polarization curve have been made on a cylindrical niobium sample, with a cylindrical niobium rod in the center.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 922258
- Report Number(s):
- JLAB-ACC-07-780; DOE/OR/23177-0277; TRN: US0801040
- Resource Relation:
- Conference: 13th Workshop on RF Superconductivity, Beijing, China, Oct. 14 - 19, 2007
- Country of Publication:
- United States
- Language:
- English
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Measurement of the high-field Q-drop in a high-purity large-grain niobium cavity for different oxidation processes