SRF2015 - List of Authors (Monaco, L.)

Paper	Title	Page
MOPB077	Vertical Tests of XFEL 3rd Harmonic Cavities	306
	D. Sertore, M. Bertucci, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, M. Moretti, R. Paparella, P. Pierini INFN/LASA, Segrate (MI), Italy A. Matheisen, M. Schmökel DESY, Hamburg, Germany C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	The 10 cavities of the EXFEL 3rd Harmonic Cryomodule have been tested and qualified, before integration in the He-tank, in our upgraded Vertical Test stand. In this paper, we report the measured RF performance of these cavities together with the main features of the test facility.
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MOPB079	Analysis of the Test Rate for European XFEL Series Cavities	316
	J. Schaffran, S. Aderhold, D. Reschke, L. Steder, N. Walker DESY, Hamburg, Germany L. Monaco INFN/LASA, Segrate (MI), Italy
	The main part of the superconducting European XFEL linear accelerator consists of 100 accelerator modules each containing eight RF-cavities. Before the installation to a module, all of these cavities will be tested at cryogenic temperatures in a vertical cryostat in the accelerator module test facility (AMTF) at DESY. This paper discusses the average vertical test rate at the present status. It should be 1 in the ideal case, but actually it’s observed to be approximately 1.5. Classification and analysis concerning the reasons for this deviation are given as well as suggestions for a reduction of the test rate for future production cycles.
	Poster MOPB079 [0.632 MB]
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MOPB086	Update and Status of Vertical Test Results of the European XFEL Series Cavities	337
	N. Walker, D. Reschke, J. Schaffran, L. Steder DESY, Hamburg, Germany L. Monaco INFN/LASA, Segrate (MI), Italy M. Wiencek IFJ-PAN, Kraków, Poland
	The series production by two industrial vendors of the 800 1.3-GHz superconducting cavities for the European XFEL has been on-going since the beginning of 2013 and will conclude towards the end of this year. As of publication some 740 cavities (~93%) have been produced at an average rate of 6 cavities per week. As part of the acceptance testing, all cavities have undergone at least one vertical RF test at 2K at the AMTF facility at DESY. The acceptance criterion for module assembly is based on the concept of a “usable gradient”, which is defined as the maximum field taking into account Q0 performance and allowed thresholds for field emission, as well as breakdown limits. Approximate 20% of the cavities have undergone further surface treatment in the DESY infrastructure to improve their usable gradient performance. In this paper we present the performance statistics of the vertical test results, as well as an analysis of the limiting criteria for the usable gradient, and finally the impact of the surface retreatment on both usable gradient and Q0.
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MOPB094	Inspection and Repair Techniques for the EXFEL Superconducting 1.3 GHz Cavities at Ettore Zanon S.p.A: Methods and Results	368
	G. Massaro, G. Corniani, N. Maragno Ettore Zanon S.p.A., Schio, Italy A. Matheisen, A. Navitski DESY, Hamburg, Germany P. Michelato, L. Monaco INFN/LASA, Segrate (MI), Italy
	The quality control of the inner surface of superconducting RF cavities is essential in order to assure high accelerating gradient and quality factor. Ettore Zanon S.p.A. (EZ) has implemented in the serial production an optical system that use an high-resolution camera, in order to detect various types of defects. This system is added to a grinding machine, that was specifically designed and built to repair imperfections of the cavities inner surface. This inspection and repair system is applied to recover performance limited cavities of the 1.3 GHz European XFEL project, where surface irregularities are detected, either by the Obacht inspection system at Desy or the optical system at EZ. The optical system and the grinding procedure are qualified using two series cavities limited in gradient and showing different types of surface defects. The performances of these cavities have been recovered to reach the specifications of the project. Until now, all the series XFEL cavities built by EZ, repaired with this technique, have shown an accelerating gradient well above the EXFEL goal.
	Poster MOPB094 [0.795 MB]
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MOPB113	Study of the Evolution of Artificial Defects on the Surface of Niobium During Electrochemical and Chemical Polishing	433
	L. Monaco, P. Michelato INFN/LASA, Segrate (MI), Italy A. Navitski, J. Schaffran, W. Singer DESY, Hamburg, Germany C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy A.L. Prudnikava, Y. Tamashevich University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The presence of defects on the inner surface of Nb superconducting RF structures might limit its final performance. For this reason, strict requirements are imposed during mechanical production of the cavities, specifically on the quality control of the inner surface of components, to avoid the presence of defects or scratches. Nevertheless, some defects may remain also after control or can arise from the following production steps. Understanding the evolution of the defect might shine new insight on its origin and help in defining possible repair techniques. This paper reports the topographical evolution of defects on a Nb sample polished with the standard recipe used for the 1.3 GHz cavities of the EXFEL project. Various artificial defects of different shape, dimensions, and thicknesses/depths, with geometrical characteristics similar to the one that may occur during the machining and handling of cavities, have been “ad hoc” produced on the sample of the same material used for the cell fabrication. Analysis shows the evolution of the shape and profile of the defects at the different polishing steps.
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TUPB018	Preparation of the 3.9 GHz System for the European XFEL Injector Commissioning	584
	P. Pierini, M. Bertucci, M. Bonezzi, A. Bosotti, J.F. Chen, M. Chiodini, P. Michelato, L. Monaco, M. Moretti, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy C. Albrecht, N. Baboi, S. Barbanotti, J. Branlard, Th. Buettner, Ł. Butkowski, T. Delfs, H. Hintz, F. Hoffmann, M. Hüning, K. Jensch, R. Jonas, R. Klos, D. Kostin, L. Lilje, C.G. Maiano, W. Maschmann, A. Matheisen, U. Mavrič, W.-D. Möller, C. Müller, P. Pierini, J. Prenting, J. Rothenburg, O. Sawlanski, M. Schlösser, M. Schmökel, A.A. Sulimov, E. Vogel DESY, Hamburg, Germany E.R. Harms Fermilab, Batavia, Illinois, USA C.R. Montiel ANL, Argonne, Illinois, USA C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	The 3.9 GHz cryomodule and RF system for the XFEL Injector is being assembled and delivered to the underground building in summer 2015, for the injector commissioning in Fall 2015. This contribution outlines the status of the activity and reports the preparation stages of the technical commissioning of the system.
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TUPB087	Development of an X-Ray Fluorescence Probe for Inner Cavity Inspection	799
	M. Bertucci, P. Michelato, L. Monaco, M. Moretti, C. Pagani INFN/LASA, Segrate (MI), Italy A. Navitski DESY, Hamburg, Germany
	The development of an x-ray fluorescence probe for detection of foreign material inclusions of the inner surface of 1.3 GHz tesla-type Niobium cavities is here presented. The setup dimensions are minimized so to access the inner cavity volume and focus on the surface of equator. Preliminary tests confirmed the system capability to detect and localize with good precision small metal inclusions of few micrograms. The results obtained from the inspection of some 1.3 GHz XFEL series production cavities are also pointed out.
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THPB010	INFN Milano - LASA Activities for ESS	1081
	P. Michelato, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, L. Monaco, M. Moretti, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy H.J. Zheng IHEP, Beijing, People's Republic of China
	INFN Milano – LASA is involved in the development and industrialization for the production of 704.4 MHz medium beta (β = 0.67) cavities for the ESS project. In this framework, we are designing a medium beta prototype cavity exploring both Large Grain and Fine Grain Niobium for its production as well as a high beta (β = 0.86) Large Grain cavity. In the meanwhile, an activity is ongoing for upgrading the LASA test facility to be able to test these kind of resonators.
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THPB035	Fabrication of the 3.9 GHz SRF Structures for the European XFEL	1162
	P. Pierini, M. Bertucci, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, M. Moretti, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy A. Gresele Ettore Zanon S.p.A., Nuclear Division, Schio, Italy C.G. Maiano, P. Pierini, E. Vogel DESY, Hamburg, Germany C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy M. Rizzi Ettore Zanon S.p.A., Schio, Italy
	One batch of 10 cavities has been completed and eight structures have been installed in the 3.9 GHz cryomodule for the European XFEL Injector operation. A second batch of 10 RF structures for a spare injector module is under fabrication. The fabrication has been performed according to the European Pressure Vessel regulations, as needed for the EXFEL operation. This paper describes the fabrication, quality control/assurance procedures and frequency preparation steps in order to achieve cavities at the correct frequency and length within the specifications.
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Paper

Title

Page

Vertical Tests of XFEL 3rd Harmonic Cavities

306

D. Sertore, M. Bertucci, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, M. Moretti, R. Paparella, P. Pierini
INFN/LASA, Segrate (MI), Italy
A. Matheisen, M. Schmökel
DESY, Hamburg, Germany
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

The 10 cavities of the EXFEL 3rd Harmonic Cryomodule have been tested and qualified, before integration in the He-tank, in our upgraded Vertical Test stand. In this paper, we report the measured RF performance of these cavities together with the main features of the test facility.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

MOPB079

Analysis of the Test Rate for European XFEL Series Cavities

316

J. Schaffran, S. Aderhold, D. Reschke, L. Steder, N. Walker
DESY, Hamburg, Germany
L. Monaco
INFN/LASA, Segrate (MI), Italy

The main part of the superconducting European XFEL linear accelerator consists of 100 accelerator modules each containing eight RF-cavities. Before the installation to a module, all of these cavities will be tested at cryogenic temperatures in a vertical cryostat in the accelerator module test facility (AMTF) at DESY. This paper discusses the average vertical test rate at the present status. It should be 1 in the ideal case, but actually it’s observed to be approximately 1.5. Classification and analysis concerning the reasons for this deviation are given as well as suggestions for a reduction of the test rate for future production cycles.

Poster MOPB079 [0.632 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

MOPB086

Update and Status of Vertical Test Results of the European XFEL Series Cavities

337

N. Walker, D. Reschke, J. Schaffran, L. Steder
DESY, Hamburg, Germany
L. Monaco
INFN/LASA, Segrate (MI), Italy
M. Wiencek
IFJ-PAN, Kraków, Poland

The series production by two industrial vendors of the 800 1.3-GHz superconducting cavities for the European XFEL has been on-going since the beginning of 2013 and will conclude towards the end of this year. As of publication some 740 cavities (~93%) have been produced at an average rate of 6 cavities per week. As part of the acceptance testing, all cavities have undergone at least one vertical RF test at 2K at the AMTF facility at DESY. The acceptance criterion for module assembly is based on the concept of a “usable gradient”, which is defined as the maximum field taking into account Q0 performance and allowed thresholds for field emission, as well as breakdown limits. Approximate 20% of the cavities have undergone further surface treatment in the DESY infrastructure to improve their usable gradient performance. In this paper we present the performance statistics of the vertical test results, as well as an analysis of the limiting criteria for the usable gradient, and finally the impact of the surface retreatment on both usable gradient and Q0.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

MOPB094

Inspection and Repair Techniques for the EXFEL Superconducting 1.3 GHz Cavities at Ettore Zanon S.p.A: Methods and Results

368

G. Massaro, G. Corniani, N. Maragno
Ettore Zanon S.p.A., Schio, Italy
A. Matheisen, A. Navitski
DESY, Hamburg, Germany
P. Michelato, L. Monaco
INFN/LASA, Segrate (MI), Italy

The quality control of the inner surface of superconducting RF cavities is essential in order to assure high accelerating gradient and quality factor. Ettore Zanon S.p.A. (EZ) has implemented in the serial production an optical system that use an high-resolution camera, in order to detect various types of defects. This system is added to a grinding machine, that was specifically designed and built to repair imperfections of the cavities inner surface. This inspection and repair system is applied to recover performance limited cavities of the 1.3 GHz European XFEL project, where surface irregularities are detected, either by the Obacht inspection system at Desy or the optical system at EZ. The optical system and the grinding procedure are qualified using two series cavities limited in gradient and showing different types of surface defects. The performances of these cavities have been recovered to reach the specifications of the project. Until now, all the series XFEL cavities built by EZ, repaired with this technique, have shown an accelerating gradient well above the EXFEL goal.

Poster MOPB094 [0.795 MB]

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MOPB113

Study of the Evolution of Artificial Defects on the Surface of Niobium During Electrochemical and Chemical Polishing

433

L. Monaco, P. Michelato
INFN/LASA, Segrate (MI), Italy
A. Navitski, J. Schaffran, W. Singer
DESY, Hamburg, Germany
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
A.L. Prudnikava, Y. Tamashevich
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The presence of defects on the inner surface of Nb superconducting RF structures might limit its final performance. For this reason, strict requirements are imposed during mechanical production of the cavities, specifically on the quality control of the inner surface of components, to avoid the presence of defects or scratches. Nevertheless, some defects may remain also after control or can arise from the following production steps. Understanding the evolution of the defect might shine new insight on its origin and help in defining possible repair techniques. This paper reports the topographical evolution of defects on a Nb sample polished with the standard recipe used for the 1.3 GHz cavities of the EXFEL project. Various artificial defects of different shape, dimensions, and thicknesses/depths, with geometrical characteristics similar to the one that may occur during the machining and handling of cavities, have been “ad hoc” produced on the sample of the same material used for the cell fabrication. Analysis shows the evolution of the shape and profile of the defects at the different polishing steps.

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

TUPB018

Preparation of the 3.9 GHz System for the European XFEL Injector Commissioning

584

P. Pierini, M. Bertucci, M. Bonezzi, A. Bosotti, J.F. Chen, M. Chiodini, P. Michelato, L. Monaco, M. Moretti, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Albrecht, N. Baboi, S. Barbanotti, J. Branlard, Th. Buettner, Ł. Butkowski, T. Delfs, H. Hintz, F. Hoffmann, M. Hüning, K. Jensch, R. Jonas, R. Klos, D. Kostin, L. Lilje, C.G. Maiano, W. Maschmann, A. Matheisen, U. Mavrič, W.-D. Möller, C. Müller, P. Pierini, J. Prenting, J. Rothenburg, O. Sawlanski, M. Schlösser, M. Schmökel, A.A. Sulimov, E. Vogel
DESY, Hamburg, Germany
E.R. Harms
Fermilab, Batavia, Illinois, USA
C.R. Montiel
ANL, Argonne, Illinois, USA
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

The 3.9 GHz cryomodule and RF system for the XFEL Injector is being assembled and delivered to the underground building in summer 2015, for the injector commissioning in Fall 2015. This contribution outlines the status of the activity and reports the preparation stages of the technical commissioning of the system.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

TUPB087

Development of an X-Ray Fluorescence Probe for Inner Cavity Inspection

799

M. Bertucci, P. Michelato, L. Monaco, M. Moretti, C. Pagani
INFN/LASA, Segrate (MI), Italy
A. Navitski
DESY, Hamburg, Germany

The development of an x-ray fluorescence probe for detection of foreign material inclusions of the inner surface of 1.3 GHz tesla-type Niobium cavities is here presented. The setup dimensions are minimized so to access the inner cavity volume and focus on the surface of equator. Preliminary tests confirmed the system capability to detect and localize with good precision small metal inclusions of few micrograms. The results obtained from the inspection of some 1.3 GHz XFEL series production cavities are also pointed out.

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

THPB010

INFN Milano - LASA Activities for ESS

1081

P. Michelato, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, L. Monaco, M. Moretti, R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
H.J. Zheng
IHEP, Beijing, People's Republic of China

INFN Milano – LASA is involved in the development and industrialization for the production of 704.4 MHz medium beta (β = 0.67) cavities for the ESS project. In this framework, we are designing a medium beta prototype cavity exploring both Large Grain and Fine Grain Niobium for its production as well as a high beta (β = 0.86) Large Grain cavity. In the meanwhile, an activity is ongoing for upgrading the LASA test facility to be able to test these kind of resonators.

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

THPB035

Fabrication of the 3.9 GHz SRF Structures for the European XFEL

1162

P. Pierini, M. Bertucci, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, M. Moretti, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
A. Gresele
Ettore Zanon S.p.A., Nuclear Division, Schio, Italy
C.G. Maiano, P. Pierini, E. Vogel
DESY, Hamburg, Germany
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
M. Rizzi
Ettore Zanon S.p.A., Schio, Italy

One batch of 10 cavities has been completed and eight structures have been installed in the 3.9 GHz cryomodule for the European XFEL Injector operation. A second batch of 10 RF structures for a spare injector module is under fabrication. The fabrication has been performed according to the European Pressure Vessel regulations, as needed for the EXFEL operation. This paper describes the fabrication, quality control/assurance procedures and frequency preparation steps in order to achieve cavities at the correct frequency and length within the specifications.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)