Preliminary Results on 'Polarized' Buffered Chemical Polishing pf a Large Grain Niobium Cavity.

Halbritter, J. ; Ciovali, G. ; Corcoran, S.

Technical Information Center Oak Ridge Tennessee

关键词: Niobium;    Superconducting cavity resonators;    Cavities;    Chemical polishing;    Q drop;   

RP-ID  :  DE2008922268

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

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.