SRF2011 - List of Authors (Kreps, G.)

Paper

Title

Page

Nine - Cell Tesla Shape Cavities Produced From Hydroformed Cells

431

W. Singer, A. Ermakov, G. Kreps, A. Matheisen, X. Singer, K. Twarowski
DESY, Hamburg, Germany
R. Crooks
Black Laboratories, L.L.C., Newport News, USA
P. Kneisel
JLAB, Newport News, Virginia, USA
I.N. Zhelezov
RAS/INR, Moscow, Russia

Production of two types of seamless niobium tubes for hydroforming of RF cavities has been developed. The first type of tubes, developed at DESY, have been spun from sheets and flow formed. The second type of tubing was developed by Black Laboratories in collaboration with the company ATI Wah Chang. These longer length tubes were extruded from a heavily deformed billet, processed for a fine-grained microstructure and flow formed. Several seamless three cell units have been produced by hydroforming at DESY. Some of the units have been treated by buffered chemical polishing and RF tested at JLab. The accelerating gradient Eacc of the units exceeded in most cases 30 MV/m. Three of the 3-cell units from the first type of tubing were combined to three 9-cell niobium cavities at the company E. Zanon. The 3-cell units from extruded tubing are welded together to the fourth 9-cell cavity at JLab. All cavities are in preparation for the RF tests at DESY and JLab. Up to now two of the cavities are electropolished and tested at DESY. The first cavity reached an accelerating gradient of Eacc of ~30 MV/m, the second one ~35 MV/m.

Poster TUPO026 [2.664 MB]

TUPO046

Results on Large Grain Nine-Cell Cavities at DESY: Gradients up to 45 MV/m after Electropolishing

490

D. Reschke, S. Aderhold, A. Gössel, J. Iversen, S. Karstensen, D. Kostin, G. Kreps, A. Matheisen, W.-D. Möller, F. Schlander, W. Singer, X. Singer, N. Steinhau Kühl, A.A. Sulimov, K. Twarowski
DESY, Hamburg, Germany

Since 2009 a series of eight nine-cell cavities (AC151 – AC158) of TESLA shape fabricated of large grain (LG) niobium material is under preparation and test at DESY. In a first step all cavities were tested after a BCP treatment. In a second step additional electro polishing is applied to all cavities. In this paper the treatment will be discussed and present results will be reported

TUPO048

Commissioning and Upgrade of Automatic Cavity Tuning Machines for the European Xfel

495

J.H. Thie, A. Gössel, J. Iversen, D. Klinke, G. Kreps, W.-D. Möller, C. Mueller, H.-B. Peters, A.A. Sulimov, D. Tischhauser
DESY, Hamburg, Germany
D. Bhogadi, R.H. Carcagno, T.N. Khabiboulline, S. Kotelnikov, A. Makulski, R. Nehring, J.M. Nogiec, W. Schappert, C. Sylvester
Fermilab, Batavia, USA

Four new tuning machines were developed and built in a collaborating effort among FNAL, KEK and DESY. Two machines were commissioned at DESY in a close teamwork with FNAL. For several months, these machines have been used regularly for the automatic tuning of different types of cavities for FLASH. Due to this operating experience and the requirements for the European XFEL cavity Specification, it was necessary to implement the following improvements: improve the precision of the eccentricity measurement; change the tuning sequence according to the different production stages in the cavity fabrication and preparation process; review and change the machine access procedures according to the safety aspects of the EC Directive of Machinery. These improvements required changes in both the mechanical parts developed by DESY and the electronics and software developed by FNAL. We report in detail about the commissioning, our tuning experience and the necessary improvements.

Poster TUPO048 [0.257 MB]

Paper	Title	Page
TUPO026	Nine - Cell Tesla Shape Cavities Produced From Hydroformed Cells	431
	W. Singer, A. Ermakov, G. Kreps, A. Matheisen, X. Singer, K. Twarowski DESY, Hamburg, Germany R. Crooks Black Laboratories, L.L.C., Newport News, USA P. Kneisel JLAB, Newport News, Virginia, USA I.N. Zhelezov RAS/INR, Moscow, Russia
	Production of two types of seamless niobium tubes for hydroforming of RF cavities has been developed. The first type of tubes, developed at DESY, have been spun from sheets and flow formed. The second type of tubing was developed by Black Laboratories in collaboration with the company ATI Wah Chang. These longer length tubes were extruded from a heavily deformed billet, processed for a fine-grained microstructure and flow formed. Several seamless three cell units have been produced by hydroforming at DESY. Some of the units have been treated by buffered chemical polishing and RF tested at JLab. The accelerating gradient Eacc of the units exceeded in most cases 30 MV/m. Three of the 3-cell units from the first type of tubing were combined to three 9-cell niobium cavities at the company E. Zanon. The 3-cell units from extruded tubing are welded together to the fourth 9-cell cavity at JLab. All cavities are in preparation for the RF tests at DESY and JLab. Up to now two of the cavities are electropolished and tested at DESY. The first cavity reached an accelerating gradient of Eacc of ~30 MV/m, the second one ~35 MV/m.
	Poster TUPO026 [2.664 MB]

TUPO046	Results on Large Grain Nine-Cell Cavities at DESY: Gradients up to 45 MV/m after Electropolishing	490
	D. Reschke, S. Aderhold, A. Gössel, J. Iversen, S. Karstensen, D. Kostin, G. Kreps, A. Matheisen, W.-D. Möller, F. Schlander, W. Singer, X. Singer, N. Steinhau Kühl, A.A. Sulimov, K. Twarowski DESY, Hamburg, Germany
	Since 2009 a series of eight nine-cell cavities (AC151 – AC158) of TESLA shape fabricated of large grain (LG) niobium material is under preparation and test at DESY. In a first step all cavities were tested after a BCP treatment. In a second step additional electro polishing is applied to all cavities. In this paper the treatment will be discussed and present results will be reported

TUPO048	Commissioning and Upgrade of Automatic Cavity Tuning Machines for the European Xfel	495
	J.H. Thie, A. Gössel, J. Iversen, D. Klinke, G. Kreps, W.-D. Möller, C. Mueller, H.-B. Peters, A.A. Sulimov, D. Tischhauser DESY, Hamburg, Germany D. Bhogadi, R.H. Carcagno, T.N. Khabiboulline, S. Kotelnikov, A. Makulski, R. Nehring, J.M. Nogiec, W. Schappert, C. Sylvester Fermilab, Batavia, USA
	Four new tuning machines were developed and built in a collaborating effort among FNAL, KEK and DESY. Two machines were commissioned at DESY in a close teamwork with FNAL. For several months, these machines have been used regularly for the automatic tuning of different types of cavities for FLASH. Due to this operating experience and the requirements for the European XFEL cavity Specification, it was necessary to implement the following improvements: improve the precision of the eccentricity measurement; change the tuning sequence according to the different production stages in the cavity fabrication and preparation process; review and change the machine access procedures according to the safety aspects of the EC Directive of Machinery. These improvements required changes in both the mechanical parts developed by DESY and the electronics and software developed by FNAL. We report in detail about the commissioning, our tuning experience and the necessary improvements.
	Poster TUPO048 [0.257 MB]