ROUGHNESS ANALYSIS OF VARIOUSLY POLISHED NIOBIUM SURFACES

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Journal of Undergraduate Research

OSTI ID:1052102

Ribeill, G; Reece, C

Niobium superconducting radio frequency (SRF) cavities have gained widespread use in accelerator systems. It has been shown that surface roughness is a determining factor in the cavities’ effi ciency and maximum accelerating potential achievable through this technology. Irregularities in the surface can lead to spot heating, undesirable local electrical fi eld enhancement and electron multipacting. Surface quality is typically ensured through the use of acid etching in a Buffered Chemical Polish (BCP) bath and electropolishing (EP). In this study, the effects of these techniques on surface morphology have been investigated in depth. The surface of niobium samples polished using different combinations of these techniques has been characterized through atomic force microscopy (AFM) and stylus profi lometry across a range of length scales. The surface morphology was analyzed using spectral techniques to determine roughness and characteristic dimensions. Experimentation has shown that this method is a valuable tool that provides quantitative information about surface roughness at different length scales. It has demonstrated that light BCP pretreatment and lower electrolyte temperature favors a smoother electropolish. These results will allow for the design of a superior polishing process for niobium SRF cavities and therefore increased accelerator operating effi ciency and power.

• Research Organization: DOESC (USDOE Office of Science (SC) (United States))
• Sponsoring Organization: USDOE Office of Science (SC)
• OSTI ID: 1052102
• Journal Information: Journal of Undergraduate Research, Journal Name: Journal of Undergraduate Research Vol. 8
• Country of Publication: United States
• Language: English