SRF2015 - List of Authors (Pagani, C.)

Paper	Title	Page
MOPB070	Preliminary Conceptual Design of the CEPC SRF System	272
	J.Y. Zhai, J. Gao, T.M. Huang, Z.C. Liu, Z.H. Mi, P. Sha, Y. Sun, H.J. Zheng IHEP, Beijing, People's Republic of China S.A. Belomestnykh BNL, Upton, Long Island, New York, USA S.A. Belomestnykh Stony Brook University, Stony Brook, USA C. Pagani INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	CEPC is a circular electron positron collider operating at 240 GeV center-of-mass energy as a Higgs factory, recently proposed by the Chinese high energy physics community. The CEPC study group, together with the FCC and ILC community, will contribute to the development of future high energy colliders and experiments which will ensure that the elementary particle physics remain a vibrant and exciting field of fundamental investigation for decades to come. Superconducting RF (SRF) system is one of the most important technical systems of CEPC and is a key to achieving its design energy and luminosity. It will dominate, with the associated RF power source and cryogenic system, the overall machine cost, efficiency and performance. The CEPC SRF system will be one of the largest and most powerful SRF accelerator installations in the world. The preliminary conceptual design of the CEPC SRF system is summarized in this paper, including the machine layout, key parameter choices and some critical issues such as HOM damping, emphasizing the new technology requirement and R&D focuses.
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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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THPB006	Improvements of Buildcavity Code	1070
	J.F. Chen, M. Moretti, C. Pagani, P. Pierini INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	Recentely, we improve the BuildCavity code, which is a graphics interface to SUPERFISH for the study of superconducting cavities of elliptical shape. Now it works with latest SUPERFISH 7 and can be installed also on newer Windows system such as Win 7 and 8. Several improvements have been done in the code. As an example, a design of ESS median-beta cavity with BuildCavity will also be presented.
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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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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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THPB004	HOM Calculations for Different Cavities and Beam Induced HOM Power Analysis of ESS	1061
	H.J. Zheng, J. Gao IHEP, Beijing, People's Republic of China J.F. Chen INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	For different design of ESS superconducting cavities, the higher order modes (HOM's) of monopoles, dipoles, quadrupoles and sextupoles are found. Their R/Q values are also calculated. Main HOM related issues are the beam instabilities and the HOM induced power especially from TM monopoles. The analysis for the beam induced HOM voltage and power in this paper showed that, if the HOM frequency is a few kHz away from the beam spectrum, it is not a problem. In order to understand the effects of the beam structure, analytic expressions are developed. With these expressions, the induced HOM voltage and power were calculated by assuming external Q for each HOM. Our analysis confirm that, with thebeam structure of ESS and a good cavity design, no special tight tolerances are required for cavity fabrication and no HOM couplers in the cavity beam pipes are planned.
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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

Preliminary Conceptual Design of the CEPC SRF System

272

J.Y. Zhai, J. Gao, T.M. Huang, Z.C. Liu, Z.H. Mi, P. Sha, Y. Sun, H.J. Zheng
IHEP, Beijing, People's Republic of China
S.A. Belomestnykh
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh
Stony Brook University, Stony Brook, USA
C. Pagani
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

CEPC is a circular electron positron collider operating at 240 GeV center-of-mass energy as a Higgs factory, recently proposed by the Chinese high energy physics community. The CEPC study group, together with the FCC and ILC community, will contribute to the development of future high energy colliders and experiments which will ensure that the elementary particle physics remain a vibrant and exciting field of fundamental investigation for decades to come. Superconducting RF (SRF) system is one of the most important technical systems of CEPC and is a key to achieving its design energy and luminosity. It will dominate, with the associated RF power source and cryogenic system, the overall machine cost, efficiency and performance. The CEPC SRF system will be one of the largest and most powerful SRF accelerator installations in the world. The preliminary conceptual design of the CEPC SRF system is summarized in this paper, including the machine layout, key parameter choices and some critical issues such as HOM damping, emphasizing the new technology requirement and R&D focuses.

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.

Export •

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

THPB006

Improvements of Buildcavity Code

1070

J.F. Chen, M. Moretti, C. Pagani, P. Pierini
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

Recentely, we improve the BuildCavity code, which is a graphics interface to SUPERFISH for the study of superconducting cavities of elliptical shape. Now it works with latest SUPERFISH 7 and can be installed also on newer Windows system such as Win 7 and 8. Several improvements have been done in the code. As an example, a design of ESS median-beta cavity with BuildCavity will also be presented.

Export •

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

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.

Export •

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

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.

Export •

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)

THPB004

HOM Calculations for Different Cavities and Beam Induced HOM Power Analysis of ESS

1061

H.J. Zheng, J. Gao
IHEP, Beijing, People's Republic of China
J.F. Chen
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

For different design of ESS superconducting cavities, the higher order modes (HOM's) of monopoles, dipoles, quadrupoles and sextupoles are found. Their R/Q values are also calculated. Main HOM related issues are the beam instabilities and the HOM induced power especially from TM monopoles. The analysis for the beam induced HOM voltage and power in this paper showed that, if the HOM frequency is a few kHz away from the beam spectrum, it is not a problem. In order to understand the effects of the beam structure, analytic expressions are developed. With these expressions, the induced HOM voltage and power were calculated by assuming external Q for each HOM. Our analysis confirm that, with thebeam structure of ESS and a good cavity design, no special tight tolerances are required for cavity fabrication and no HOM couplers in the cavity beam pipes are planned.

Export •

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.

Export •

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)