IPAC2017 - List of Authors (Bosotti, A.)

Paper	Title	Page
MOPVA058	Commissioning and Operation Experience of the 3.9 GHz System in the EXFEL Linac	999
	C.G. Maiano, J. Branlard, M. Hüning, M. Omet, P. Pierini, E. Vogel DESY, Hamburg, Germany A. Bosotti, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy
	The European X-ray Free Electron Laser (EXFEL) injector linac hosts a 3.9~GHz module (AH1) for beam longitudinal phase space manipulation after the first acceleration stage, in order for the linac to deliver the high current beams with sufficiently low emittance for the production of 1 Angstrom FEL light to the experimental users. The module was technically commissioned in December 2015 and operated well above its nominal performances during the Injector Run from January to July 2016. Its operation has restarted in January 2017 with the startup of the whole facility, and the system met the design beam specifications after the bunch compression stages. A brief review of the commissioning and first operation experience of the RF system are presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA058
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MOPVA060	Fabrication and Treatment of the ESS Medium Beta Prototype Cavities	1003
	L. Monaco, A. Bellandi, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, P. Michelato, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy S. Pirani ESS, Lund, Sweden
	In view of the Medium Beta series cavities production at the industry for the European Spallation Source project, INFN Milano - LASA design prototypes have been fully produced at Ettore Zanon S.p.A. with our supervision. Based on our experience on the production of 1.3 GHz and 3.9 GHz E-XFEL series cavities, we set-up and applied an external quality control activity of the overall production of the prototype cavity, starting from the row materials to the ready to be tested cavity. In this paper, we report the strategy we have adopted on the overall production, mechanical and surface treatments, frequency measurement of subcomponents and cavities and the obtained results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA060
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MOPVA061	Quench and Field Emission Diagnostics for the ESS Medium-Beta Prototypes Vertical Tests at LASA	1007
	M. Bertucci, A. Bellandi, A. Bignami, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy S. Pirani ESS, Lund, Sweden
	In order to investigate the possible causes of premature thermal breakdown and performance degradation, several diagnostic techniques have been employed during the vertical tests of the Fine and Large Grain ESS Medium Beta prototypes cavities. The whole equipment, which includes second sound, fast thermometry, photodiode x ray detectors and an external NaI scintillator, is here described and the results so far obtained during the vertical tests presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA061
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MOPVA062	Test, Diagnostics and Computed Tomographic Inspection of a Large Grain 3.9 GHz Prototype Cavity	1011
	M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy G. Ciovati, G.R. Myneni JLab, Newport News, Virginia, USA C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	A large grain 3.9 GHz prototype cavity made of RRR = 10⁵ ±10 has been tested at LASA. The cavity suffered of quench at moderate levels of accelerating field, for all nine fundamental pass-band modes. Several diagnostic techniques have been employed to determine the quench positions, which occur close to significant grain-boundary steps, visible from the external cavity surface. The cavity has been scanned with a high resolution X-ray tomographic machine, confirming the existence of remarkable topographic features on the inner RF surface at the suspected quench positions. A strategy for a future surface treatment for recover the cavity performances is here presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA062
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MOPVA063	Vertical Tests of ESS Medium Beta Prototype Cavities at LASA	1015
	A. Bosotti, A. Bellandi, M. Bertucci, A. Bignami, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy S. Pirani ESS, Lund, Sweden
	In the framework of the INFN activity related to the European Spallation Source collaboration, the LASA infrastructure has been renewed to allow the qualification, in its vertical cryostat, of the 704 MHz medium beta cavity prototypes. A new cryogenic insert has been realized, fully equipped with dedicated mechanical supports, vacuum, thermal sensors and quench diagnostic systems. The RF test station has been upgraded as well with a new PLL electronics rack. The first beta 0.67 cavity prototype designed and produced by INFN Milano has been successfully cold tested at 2.0 K temperature, outperforming the ESS specifications. The technical features of LASA infrastructure, the design of novel components and the experimental results of cavities cold-tests are thoroughly described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA063
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MOPVA064	Multipacting Study in INFN-LASA ESS Medium-Beta Cavity	1019
	J.F. Chen, M. Bertucci, A. Bosotti, P. Michelato, L. Monaco, C. Pagani, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy S. Pirani ESS, Lund, Sweden
	We present Multipacting studies in ESS Medium-Beta cavities of INFN-LASA design with both simulation and experimental results. The simulation on the ideal cavity shape with both FishPact and MultiPac2.1 codes shows that multipacting appears in a very small region near equator where the weld seam exists. A simulation with more realistic cavity shape considering the weld seam at cell equators has also been done out showing similar results for end cell but a remarkable mitigation for inner cell. During the vertical tests at LASA, Multipacting is frequently observed but with no limitation to the cavity performance, which well confirms the MP predicted by the simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA064
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MOPVA066	Limits for the Operation of the European XFEL 3.9 GHz System in CW Mode	1023
	P. Pierini, A. Bosotti, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy J. Branlard, D. Kostin, C.G. Maiano, W.-D. Möller, P. Pierini, D. Reschke, J.K. Sekutowicz, E. Vogel DESY, Hamburg, Germany
	Future upgrades of the European XFEL (EXFEL) facility may require driving the linac at higher duty factor, possibly extending to CW mode at reduced gradients. A preliminary analysis for the accelerator modules has been presented in the EXFEL TDR, but no precise assessment has been performed so far for the present 3.9 GHz system design. By making use of data collected during the commissioning and operation phase of the EXFEL injector system, we discuss here an estimate for the limits of CW operation of the present system and a plan for its possible experimental verification with existing available cavities and the EXFEL spare module.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA066
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MOPVA068	Experience on Design, Fabrication and Testing of a Large Grain ESS Medium Beta Prototype Cavity	1027
	D. Sertore, A. Bellandi, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy S. Pirani ESS, Lund, Sweden
	We report on the design, fabrication and testing of an ESS Medium Beta prototype cavity made with Large Grain Niobium sheets sliced from an ingot provided by CBMM. The peculiar choices during the fabrication process related to the Large Grain Niobium material are described. We present also the results of the cavity test at cryogenic temperature and the dedicated quench diagnostic.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA068
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MOPVA091	Investigation of HOM Frequency Shifts Induced by Mechanical Tolerances	1071
	S. Pirani, M. Eshraqi, M. Lindroos ESS, Lund, Sweden A. Bosotti, J.F. Chen, P. Michelato, C. Pagani, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy T.P.Å. Åkesson Lund University, Department of Physics, Lund, Sweden
	We present Higher Order Mode (HOM) studies on ESS Medium-Beta cavity of INFN-LASA design, including both simulation and measurement results. Mechanical tolerances of the fabrication process might shift HOMs frequencies toward harmonics of the bunch frequency. Both simulation and measurements at room and cryogenic temperature show that INFN LASA cavity is fully compatible with ESS requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA091
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Commissioning and Operation Experience of the 3.9 GHz System in the EXFEL Linac

999

C.G. Maiano, J. Branlard, M. Hüning, M. Omet, P. Pierini, E. Vogel
DESY, Hamburg, Germany
A. Bosotti, R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy

The European X-ray Free Electron Laser (EXFEL) injector linac hosts a 3.9~GHz module (AH1) for beam longitudinal phase space manipulation after the first acceleration stage, in order for the linac to deliver the high current beams with sufficiently low emittance for the production of 1 Angstrom FEL light to the experimental users. The module was technically commissioned in December 2015 and operated well above its nominal performances during the Injector Run from January to July 2016. Its operation has restarted in January 2017 with the startup of the whole facility, and the system met the design beam specifications after the bunch compression stages. A brief review of the commissioning and first operation experience of the RF system are presented here.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA058

Export •

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

MOPVA060

Fabrication and Treatment of the ESS Medium Beta Prototype Cavities

1003

L. Monaco, A. Bellandi, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, P. Michelato, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
S. Pirani
ESS, Lund, Sweden

In view of the Medium Beta series cavities production at the industry for the European Spallation Source project, INFN Milano - LASA design prototypes have been fully produced at Ettore Zanon S.p.A. with our supervision. Based on our experience on the production of 1.3 GHz and 3.9 GHz E-XFEL series cavities, we set-up and applied an external quality control activity of the overall production of the prototype cavity, starting from the row materials to the ready to be tested cavity. In this paper, we report the strategy we have adopted on the overall production, mechanical and surface treatments, frequency measurement of subcomponents and cavities and the obtained results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA060

Export •

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

MOPVA061

Quench and Field Emission Diagnostics for the ESS Medium-Beta Prototypes Vertical Tests at LASA

1007

M. Bertucci, A. Bellandi, A. Bignami, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
S. Pirani
ESS, Lund, Sweden

In order to investigate the possible causes of premature thermal breakdown and performance degradation, several diagnostic techniques have been employed during the vertical tests of the Fine and Large Grain ESS Medium Beta prototypes cavities. The whole equipment, which includes second sound, fast thermometry, photodiode x ray detectors and an external NaI scintillator, is here described and the results so far obtained during the vertical tests presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA061

Export •

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

MOPVA062

Test, Diagnostics and Computed Tomographic Inspection of a Large Grain 3.9 GHz Prototype Cavity

1011

M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy
G. Ciovati, G.R. Myneni
JLab, Newport News, Virginia, USA
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

A large grain 3.9 GHz prototype cavity made of RRR = 10⁵ ±10 has been tested at LASA. The cavity suffered of quench at moderate levels of accelerating field, for all nine fundamental pass-band modes. Several diagnostic techniques have been employed to determine the quench positions, which occur close to significant grain-boundary steps, visible from the external cavity surface. The cavity has been scanned with a high resolution X-ray tomographic machine, confirming the existence of remarkable topographic features on the inner RF surface at the suspected quench positions. A strategy for a future surface treatment for recover the cavity performances is here presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA062

Export •

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

MOPVA063

Vertical Tests of ESS Medium Beta Prototype Cavities at LASA

1015

A. Bosotti, A. Bellandi, M. Bertucci, A. Bignami, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
S. Pirani
ESS, Lund, Sweden

In the framework of the INFN activity related to the European Spallation Source collaboration, the LASA infrastructure has been renewed to allow the qualification, in its vertical cryostat, of the 704 MHz medium beta cavity prototypes. A new cryogenic insert has been realized, fully equipped with dedicated mechanical supports, vacuum, thermal sensors and quench diagnostic systems. The RF test station has been upgraded as well with a new PLL electronics rack. The first beta 0.67 cavity prototype designed and produced by INFN Milano has been successfully cold tested at 2.0 K temperature, outperforming the ESS specifications. The technical features of LASA infrastructure, the design of novel components and the experimental results of cavities cold-tests are thoroughly described in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA063

Export •

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

MOPVA064

Multipacting Study in INFN-LASA ESS Medium-Beta Cavity

1019

J.F. Chen, M. Bertucci, A. Bosotti, P. Michelato, L. Monaco, C. Pagani, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
S. Pirani
ESS, Lund, Sweden

We present Multipacting studies in ESS Medium-Beta cavities of INFN-LASA design with both simulation and experimental results. The simulation on the ideal cavity shape with both FishPact and MultiPac2.1 codes shows that multipacting appears in a very small region near equator where the weld seam exists. A simulation with more realistic cavity shape considering the weld seam at cell equators has also been done out showing similar results for end cell but a remarkable mitigation for inner cell. During the vertical tests at LASA, Multipacting is frequently observed but with no limitation to the cavity performance, which well confirms the MP predicted by the simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA064

Export •

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

MOPVA066

Limits for the Operation of the European XFEL 3.9 GHz System in CW Mode

1023

P. Pierini, A. Bosotti, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
J. Branlard, D. Kostin, C.G. Maiano, W.-D. Möller, P. Pierini, D. Reschke, J.K. Sekutowicz, E. Vogel
DESY, Hamburg, Germany

Future upgrades of the European XFEL (EXFEL) facility may require driving the linac at higher duty factor, possibly extending to CW mode at reduced gradients. A preliminary analysis for the accelerator modules has been presented in the EXFEL TDR, but no precise assessment has been performed so far for the present 3.9 GHz system design. By making use of data collected during the commissioning and operation phase of the EXFEL injector system, we discuss here an estimate for the limits of CW operation of the present system and a plan for its possible experimental verification with existing available cavities and the EXFEL spare module.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA066

Export •

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

MOPVA068

Experience on Design, Fabrication and Testing of a Large Grain ESS Medium Beta Prototype Cavity

1027

D. Sertore, A. Bellandi, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
S. Pirani
ESS, Lund, Sweden

We report on the design, fabrication and testing of an ESS Medium Beta prototype cavity made with Large Grain Niobium sheets sliced from an ingot provided by CBMM. The peculiar choices during the fabrication process related to the Large Grain Niobium material are described. We present also the results of the cavity test at cryogenic temperature and the dedicated quench diagnostic.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA068

Export •

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

MOPVA091

Investigation of HOM Frequency Shifts Induced by Mechanical Tolerances

1071

S. Pirani, M. Eshraqi, M. Lindroos
ESS, Lund, Sweden
A. Bosotti, J.F. Chen, P. Michelato, C. Pagani, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
T.P.Å. Åkesson
Lund University, Department of Physics, Lund, Sweden

We present Higher Order Mode (HOM) studies on ESS Medium-Beta cavity of INFN-LASA design, including both simulation and measurement results. Mechanical tolerances of the fabrication process might shift HOMs frequencies toward harmonics of the bunch frequency. Both simulation and measurements at room and cryogenic temperature show that INFN LASA cavity is fully compatible with ESS requirements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA091

Export •

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