IPAC2018 - List of Authors (Checchin, M.)

Paper	Title	Page
WEPMK016	New Insight on Nitrogen Infusion Revealed by Successive Nanometric Material Removal	2665
	M. Checchin, A. Grassellino, M. Martinello, O.S. Melnychuk, S. Posen, A.S. Romanenko, D.A. Sergatskov Fermilab, Batavia, Illinois, USA
	In this study we present new insight on low temperature nitrogen infusion on bulk niobium superconducting radio-frequency (SRF) cavities. Nitrogen infusion is a thermal treatment recently discovered at Fermilab that allows to reach high accelerating gradients, of the order of 45MV/m, with high Q-factors, of the order of 2 · 10¹⁰. Detailed depth dependent RF studies (by means of subsequent HF rinses) and comparisonwith SIMS results pinpointed interstitial nitrogen as the responsible for the improved performance and uncovered the extension of its profile inside the material.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK016
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WEPML013	Anti-Q-slope enhancement in high-frequency niobium cavities	2707
	M. Martinello, S. Aderhold, S.K. Chandrasekaran, M. Checchin, A. Grassellino, O.S. Melnychuk, S. Posen, A.S. Romanenko, D.A. Sergatskov Fermilab, Batavia, Illinois, USA
	N-doped 1.3 GHz niobium cavities showed for the first time the so-called anti-Q-slope, i.e. the increasing of the Q-factor as a function of the accelerating field. It was verified that the anti-Q-slope is consequence of the decreasing of the temperature-dependent component of the surface resistance as a function of the field. This trend is opposite compared to the increasing of the surface resistance previously observed in 1.3 GHz standard (EP, BCP, 120 C baked) niobium cavities. The effect of the different state-of-the-art surface treatments on the field dependence of the surface resistance is studied for 650 MHz, 1.3 GHz, 2.6 GHz and 3.9 Ghz cavities. This proceeding shows that the field dependence of the temperature-dependent component of the surface resistance has a strong frequency dependence and that the anti-Q-slope may appear even in clean niobium cavities if the resonant frequency is high enough, suggesting new routes toward the understanding of the anti-Q-slope effect.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML013
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

New Insight on Nitrogen Infusion Revealed by Successive Nanometric Material Removal

2665

M. Checchin, A. Grassellino, M. Martinello, O.S. Melnychuk, S. Posen, A.S. Romanenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA

In this study we present new insight on low temperature nitrogen infusion on bulk niobium superconducting radio-frequency (SRF) cavities. Nitrogen infusion is a thermal treatment recently discovered at Fermilab that allows to reach high accelerating gradients, of the order of 45MV/m, with high Q-factors, of the order of 2 · 10¹⁰. Detailed depth dependent RF studies (by means of subsequent HF rinses) and comparisonwith SIMS results pinpointed interstitial nitrogen as the responsible for the improved performance and uncovered the extension of its profile inside the material.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPML013

Anti-Q-slope enhancement in high-frequency niobium cavities

2707

M. Martinello, S. Aderhold, S.K. Chandrasekaran, M. Checchin, A. Grassellino, O.S. Melnychuk, S. Posen, A.S. Romanenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA

N-doped 1.3 GHz niobium cavities showed for the first time the so-called anti-Q-slope, i.e. the increasing of the Q-factor as a function of the accelerating field. It was verified that the anti-Q-slope is consequence of the decreasing of the temperature-dependent component of the surface resistance as a function of the field. This trend is opposite compared to the increasing of the surface resistance previously observed in 1.3 GHz standard (EP, BCP, 120 C baked) niobium cavities. The effect of the different state-of-the-art surface treatments on the field dependence of the surface resistance is studied for 650 MHz, 1.3 GHz, 2.6 GHz and 3.9 Ghz cavities. This proceeding shows that the field dependence of the temperature-dependent component of the surface resistance has a strong frequency dependence and that the anti-Q-slope may appear even in clean niobium cavities if the resonant frequency is high enough, suggesting new routes toward the understanding of the anti-Q-slope effect.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)