Document Type

Poster

Publication Date

2011

Publication Title

15th International Conference on RF Superconductivity

Pages

THPO032

Conference Name

15th International Conference on RF Superconductivity, 25-29 July 2011, Chicago, Illinois

Abstract

Niobium (Nb) is the material of choice for superconducting radio frequency (SRF) cavities due to its high critical temperature and critical magnetic field. Interstitial impurity elements such as H directly influence the efficiency of these cavities. Quantification of H in Nb is difficult since H is extremely mobile in Nb with a very high diffusion coefficient even at room temperature. In the presented work, Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) was used to characterize H in Nb over a wide temperature range (160°K to 475°K) in situ to check for changes in mobility. Multiple experiments showed that as the specimen temperature is decreased below 300 °K, the H/Nb intensity changes by first increasing and then decreasing drastically at temperatures below 200°K. As specimen temperature is increased from 300°K to 450°K, the H/Nb intensity decreases. Remarkably, the H intensity with respect to Nb increases with time at 475°K (approximately 200°C). Correlation between this data and the H-Nb phase diagram appears to account for the H behaviour.

Comments

Jefferson Lab report numbers: "JLAB-ACC-11-1454, DOE/OR/23177-2413"

Original Publication Citation

Maheshwari, P., Myneni, G. R., Ciovati, G., Zhou, C., Stevie, F. A., Rigsbee, J. M., Griffis, D. P., & Batchelor, A. D. (2011). TOF-SIMS Analysis of Hydrogen in Niobium, from 160°K to 475°K. 15th International Conference on RF Superconductivity, Chicago, Illinois. https://misportal.jlab.org/sti/publications/11943

ORCID

0000-0001-9316-7704 (Ciovati)

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