SRF2019 - List of Authors (Vonk, V.)

Paper	Title	Page
TUFUA6	Surface Analysis of Niobium After Thermal/Gas Treatments via Samples - Review
	A. Dangwal Pandey, T.F. Keller, H. Noei, D. Reschke, J. Schaffran, G.D.L. Semione, V. Vonk, H. Weise, M. Wenskat DESY, Hamburg, Germany C. Bate, A. Stierle University of Hamburg, Hamburg, Germany
	Thermal treatments of SRF Nb cavities - including the well-established 120°C bake and the recently reported N-infusion - are shown to improve the cavity performance significantly; however, the underlying physical phenomenon is not fully understood. A short review will be presented on surface characterization of niobium material subjected to various thermal and gas exposure protocols and how the findings correlate with observed SRF properties. Moreover, recent results obtained on single-crystal Nb samples - heated in different vacuum environments and characterised by means of X-ray photoelectron spectroscopy and grazing-incidence X-ray diffraction, electron microscopy, energy dispersive X-ray spectroscopy and time-of-flight secondary ion mass spectroscopy will be discussed.
	Slides TUFUA6 [6.968 MB]
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MOP023	Nitrogen Infusion Sample R&D at DESY	77
SUSP002	use link to see paper's listing under its alternate paper code
	C. Bate, A. Dangwal Pandey, A. Ermakov, B. Foster, T.F. Keller, D. Reschke, J. Schaffran, S. Sievers, N. Walker, H. Weise, M. Wenskat DESY, Hamburg, Germany W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany G.D.L. Semione, V. Vonk DESY Nanolab, FS-NL, Hamburg, Germany A. Stierle University of Hamburg, Hamburg, Germany
	The European XFEL continuous wave upgrade requires cavities with reduced surface resistance (high Q-values) for high duty cycle while maintaining high accelerating gradient for short-pulse operation. A possible way to meet the requirements is the so-called nitrogen infusion procedure. However, a fundamental understanding and a theoretical model of this method are still missing. The approach shown here is based on sample R&D, with the goal to identify key parameters of the process and establish a stable, reproducible recipe. To understand the underlying processes of the surface evolution, which gives improved cavity performance, advanced surface analysis techniques (e.g. SEM/EDX, TEM, XPS, TOF-SIMS) are utilized. Additionally, a small furnace just for samples was set up to change and explore the parameter space of the infusion recipe. Results of these analyses, their implications for the cavity R&D and next steps are presented.
	Poster MOP023 [3.759 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP023
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

TUFUA6

Surface Analysis of Niobium After Thermal/Gas Treatments via Samples - Review

A. Dangwal Pandey, T.F. Keller, H. Noei, D. Reschke, J. Schaffran, G.D.L. Semione, V. Vonk, H. Weise, M. Wenskat
DESY, Hamburg, Germany
C. Bate, A. Stierle
University of Hamburg, Hamburg, Germany

Thermal treatments of SRF Nb cavities - including the well-established 120°C bake and the recently reported N-infusion - are shown to improve the cavity performance significantly; however, the underlying physical phenomenon is not fully understood. A short review will be presented on surface characterization of niobium material subjected to various thermal and gas exposure protocols and how the findings correlate with observed SRF properties. Moreover, recent results obtained on single-crystal Nb samples - heated in different vacuum environments and characterised by means of X-ray photoelectron spectroscopy and grazing-incidence X-ray diffraction, electron microscopy, energy dispersive X-ray spectroscopy and time-of-flight secondary ion mass spectroscopy will be discussed.

Slides TUFUA6 [6.968 MB]

Export •

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

MOP023

Nitrogen Infusion Sample R&D at DESY

77

SUSP002

use link to see paper's listing under its alternate paper code

C. Bate, A. Dangwal Pandey, A. Ermakov, B. Foster, T.F. Keller, D. Reschke, J. Schaffran, S. Sievers, N. Walker, H. Weise, M. Wenskat
DESY, Hamburg, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
G.D.L. Semione, V. Vonk
DESY Nanolab, FS-NL, Hamburg, Germany
A. Stierle
University of Hamburg, Hamburg, Germany

The European XFEL continuous wave upgrade requires cavities with reduced surface resistance (high Q-values) for high duty cycle while maintaining high accelerating gradient for short-pulse operation. A possible way to meet the requirements is the so-called nitrogen infusion procedure. However, a fundamental understanding and a theoretical model of this method are still missing. The approach shown here is based on sample R&D, with the goal to identify key parameters of the process and establish a stable, reproducible recipe. To understand the underlying processes of the surface evolution, which gives improved cavity performance, advanced surface analysis techniques (e.g. SEM/EDX, TEM, XPS, TOF-SIMS) are utilized. Additionally, a small furnace just for samples was set up to change and explore the parameter space of the infusion recipe. Results of these analyses, their implications for the cavity R&D and next steps are presented.

Poster MOP023 [3.759 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP023

About •

paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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