LINAC2018 - List of Authors (Schaffran, J.)

Paper	Title	Page
TUPO028	Retreatment of European XFEL Series Cavities at DESY as Part of the Repair of European XFEL Accelerating Modules	384
	S. Sievers, N. Krupka, D. Reschke, S. Saegebarth, J. Schaffran, M. Schalwat, P. Schilling, M. Schmökel, N. Steinhau-Kühl, E. Vogel, H. Weise, B. van der Horst DESY, Hamburg, Germany M. Wiencek IFJ-PAN, Kraków, Poland
	For the European XFEL 10² accelerating modules were built and tested. Several accelerating modules had to be reworked due to different kinds of non-conformities. The extent of this rework varied greatly. At the end of production four accelerating modules could not be qualified in time before the tunnel installation was to be finished in September 2016. Meanwhile the cavity strings of two of these accelerating modules have been disassembled in the DESY clean room. The cavities have been retreated at DESY either by additional high pressure water rinsing or BCP flash chemical treatment. All cavities were vertically tested and 15 out of 16 were qualified for the reassembly of the cavity strings. One accelerating module will be reassembled completely and tested until the end of 2018; the other will follow in the first half of 2019. We report on retreatment procedures and performance of these cavities.
	Poster TUPO028 [1.662 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO028
About •	paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TH2A01	Nitrogen Infusion R&D for CW Operation at DESY	652
	M. Wenskat, A.D. Dangwal Pandey, B. Foster, T.F. Keller, D. Reschke, J. Schaffran, S. Sievers, N. Walker, H. Weise DESY, Hamburg, Germany C. Bate, G.D.L. Semione, A. Stierle University of Hamburg, Hamburg, Germany B. Foster Oxford University, Physics Department, Oxford, Oxon, United Kingdom B. Foster University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The European XFEL cw upgrade requires cavities with reduced surface resistance (high Q-values) for high duty-cycle while maintaining high accelerating gradient for short-pulse operation. To improve on European XFEL performance, a recently discovered treatment is investigated: The so called Nitrogen-infusion. The recent test results of the cavity based R&D and the progress of the relevant infrastructure is presented. The aim of this approach is to establish a stable, reproducible recipe and to identify all key parameters for this process. In parallel, advanced surface analyses, such as SEM/EDX, TEM, XPS, XRR, GIXRD and TOF-SIMS, of samples after in-situ treatment, cut-outs of cavities and samples treated together with cavities are done. The aim of this approach is to understand the underlying processes of the material evolution, resulting in the improved performance. Results of these analyses, their implications for the cavity R&D, and next steps are presented.
	Slides TH2A01 [4.597 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH2A01
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Retreatment of European XFEL Series Cavities at DESY as Part of the Repair of European XFEL Accelerating Modules

384

S. Sievers, N. Krupka, D. Reschke, S. Saegebarth, J. Schaffran, M. Schalwat, P. Schilling, M. Schmökel, N. Steinhau-Kühl, E. Vogel, H. Weise, B. van der Horst
DESY, Hamburg, Germany
M. Wiencek
IFJ-PAN, Kraków, Poland

For the European XFEL 10² accelerating modules were built and tested. Several accelerating modules had to be reworked due to different kinds of non-conformities. The extent of this rework varied greatly. At the end of production four accelerating modules could not be qualified in time before the tunnel installation was to be finished in September 2016. Meanwhile the cavity strings of two of these accelerating modules have been disassembled in the DESY clean room. The cavities have been retreated at DESY either by additional high pressure water rinsing or BCP flash chemical treatment. All cavities were vertically tested and 15 out of 16 were qualified for the reassembly of the cavity strings. One accelerating module will be reassembled completely and tested until the end of 2018; the other will follow in the first half of 2019. We report on retreatment procedures and performance of these cavities.

Poster TUPO028 [1.662 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO028

About •

paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

Export •

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

TH2A01

Nitrogen Infusion R&D for CW Operation at DESY

652

M. Wenskat, A.D. Dangwal Pandey, B. Foster, T.F. Keller, D. Reschke, J. Schaffran, S. Sievers, N. Walker, H. Weise
DESY, Hamburg, Germany
C. Bate, G.D.L. Semione, A. Stierle
University of Hamburg, Hamburg, Germany
B. Foster
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
B. Foster
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The European XFEL cw upgrade requires cavities with reduced surface resistance (high Q-values) for high duty-cycle while maintaining high accelerating gradient for short-pulse operation. To improve on European XFEL performance, a recently discovered treatment is investigated: The so called Nitrogen-infusion. The recent test results of the cavity based R&D and the progress of the relevant infrastructure is presented. The aim of this approach is to establish a stable, reproducible recipe and to identify all key parameters for this process. In parallel, advanced surface analyses, such as SEM/EDX, TEM, XPS, XRR, GIXRD and TOF-SIMS, of samples after in-situ treatment, cut-outs of cavities and samples treated together with cavities are done. The aim of this approach is to understand the underlying processes of the material evolution, resulting in the improved performance. Results of these analyses, their implications for the cavity R&D, and next steps are presented.

Slides TH2A01 [4.597 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH2A01

About •

paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

Export •

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