Document Type

Article

Publication Date

2006

DOI

10.1063/1.2220059

Publication Title

Applied Physics Letters

Volume

89

Issue

2

Pages

022507 (4 pp.)

Abstract

Radio-frequency (rf) superconducting cavities made of high purity niobium are widely used to accelerate charged particle beams in particle accelerators. The major limitation to achieve rf field values approaching the theoretical limit for niobium is represented by “anomalous” losses which degrade the quality factor of the cavities starting at peak surface magnetic fields of about 100mT, in the absence of field emission. These high field losses are often referred to as Q drop. It has been observed that the Q drop is drastically reduced by baking the cavities at 120°C for about 48h under ultrahigh vacuum. An improved oxygen diffusion model for the niobium-oxide system is proposed to explain the benefit of the low-temperature baking on the Q drop in niobium superconducting rf cavities. The model shows that baking at 120°C for 48h allows oxygen to diffuse away from the surface, and therefore increasing the lower critical field towards the value for pure niobium.

Rights

© 2006 American Institute of Physics.

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in (citation of published article) and may be found at (URL/link for published article abstract)

Original Publication Citation

Ciovati, G. (2006). Improved oxygen diffusion model to explain the effect of low-temperature baking on high field losses in niobium superconducting cavities. Applied Physics Letters, 89(2), Article 022507. https://doi.org/10.1063/1.2220059

ORCID

0000-0001-9316-7704 (Ciovati)

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