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Title: SRF niobium characterization using SIMS and FIB-TEM

Journal Article · · AIP Conference Proceedings
DOI:https://doi.org/10.1063/1.4935321· OSTI ID:22492688
 [1]
  1. Analytical Instrumentation Facility, North Carolina State University, 2410 Campus Shore Dr., Raleigh, NC 27695, US (United States)

Our understanding of superconducting radio frequency (SRF) accelerator cavities has been improved by elemental analysis at high depth resolution and by high magnification microscopy. This paper summarizes the technique development and the results obtained on poly-crystalline, large grain, and single crystal SRF niobium. Focused ion beam made possible sample preparation using transmission electron microscopy and the images obtained showed a very uniform oxide layer for all samples analyzed. Secondary ion mass spectrometry indicated the presence of a high concentration of hydrogen and the hydrogen content exhibited a relationship with improvement in performance. Depth profiles of carbon, nitrogen, and oxygen did not show major differences with heat treatment. Niobium oxide less than 10 nm thick was shown to be an effective hydrogen barrier. Niobium with titanium contamination showed unexpected performance improvement.

OSTI ID:
22492688
Journal Information:
AIP Conference Proceedings, Vol. 1687, Issue 1; Conference: Ingot niobium summary workshop, Newport News, VA (United States), 4 Dec 2015; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
Country of Publication:
United States
Language:
English