SRF2015 - List of Authors (Matheisen, A.)

Paper	Title	Page
MOPB075	Experiences on Retreatment of EU-XFEL Series Cavities at DESY	296
	A. Matheisen, N. Krupka, S. Saegebarth, P. Schilling, N. Steinhau-Kühl, B. van der Horst DESY, Hamburg, Germany
	For the European XFEL (EU-XFEL), two industrial companies are responsible for the manufacture and surface preparation of the eight hundred superconducting cavities. The companies had to strictly follow the XFEL specification and document all production and preparation steps. No performance guaranties were required. Each cavity delivered by industry to DESY is tested in a vertical test at 2K. Resonators not reaching the performances defined for application at the EU-XFEL linear accelerator modules or showing leakage during cold RF tests have undergone a subsequent retreatment at DESY. Nearly 20% of the cavity production required retreatment, most of them by an additional high pressure rinsing. Some cavities received additional chemical treatment by BCP flash after the initial HPR did not cure the problem. The analysis of retreatments and quality control data available from the retreatment sequences and the workflow of retreatment will be presented.
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MOPB076	Horizontal RF Test of a Fully Equipped 3.9 GHz Cavity for the European XFEL in the DESY AMTF	301
	C.G. Maiano, C. Albrecht, R. Bospflug, J. Branlard, Ł. Butkowski, T. Delfs, J. Eschke, A. Gössel, F. Hoffmann, M. Hüning, K. Jensch, R. Jonas, R. Klos, D. Kostin, W. Maschmann, A. Matheisen, U. Mavrič, W.-D. Möller, C. Müller, K. Mueller, B. Petersen, P. Pierini, J. Rothenburg, O. Sawlanski, M. Schmökel, A.A. Sulimov, E. Vogel DESY, Hamburg, Germany A. Bosotti, M. Moretti, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy E.R. Harms Fermilab, Batavia, Illinois, USA C.R. Montiel ANL, Argonne, Illinois, USA S. Pivovarov BINP SB RAS, Novosibirsk, Russia
	In order to validate the cavity package concept before the module preparation for the European XFEL Injector, one 3.9 GHz cavity, complete with magnetic shielding, power coupler and frequency tuner was tested in a specially designed single cavity cryomodule in one of the caves of the DESY Accelerator Module Test Facility (AMTF). The cavity was tested in high power pulsed operation up to the quench limit of 24 MV/m, above the vertical test qualifications and all subsystems under test (coupler, tuner, waveguide tuners, LLRF system) were qualified to design performances.
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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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MOPB090	Analysis of Degraded Cavities in Prototype Modules for the European XFEL	355
	S. Aderhold Fermilab, Batavia, Illinois, USA S. Aderhold, D. Kostin, A. Matheisen, A. Navitski, D. Reschke DESY, Hamburg, Germany
	In-between the fabrication and the operation in an accelerator the performance of superconducting RF cavities is typically tested several times. Although the assembly is done under very controlled conditions in a clean room, it is observed from time to time that a cavity with good performance in the vertical acceptance test shows deteriorated performance in the accelerator module afterwards. This work presents the analysis of several such cavities that have been disassembled from modules of the prototype phase for the European XFEL for detailed investigation like additional rf tests, optical inspection and replica.
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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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MOPB102	Comments on Electropolishing at Ettore Zanon SpA at the End of EXFEL Production	394
	M. Rizzi, G. Corniani Ettore Zanon S.p.A., Schio, Italy A. Matheisen DESY, Hamburg, Germany P. Michelato INFN/LASA, Segrate (MI), Italy
	In 2013 a new horizontal Electropolishing facility was developed and implemented by Ettore Zanon SpA (EZ) for the treatment of cavities for the European XFEL series production. More than 300 cavities have been treated. Electropolishing has been used for two applications: bulk removal and recovering of cavities with surface defects. Treatment settings have been analysed and compared with cavities performances to verify possible influences of the various parameters. Main parameters considered are treatment time, voltage and current, that together define average thickness removal. We present here the results of these investigation. The facility and process in use are also presented, together with possible next upgrade of the system, facing the new production of cavities for the LCLSII project.
	Poster MOPB102 [1.535 MB]
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MOPB103	Vertical Electro-Polishing at DESY of a 1.3 GHz Gun Cavity for CW Application	399
	N. Steinhau-Kühl, R. Bandelmann, D. Kostin, A. Matheisen, M. Schmökel, J.K. Sekutowicz DESY, Hamburg, Germany
	Superconducting gun cavities for cw operation in accelerators are under study. In 2003 a three-and-a-half cell gun cavity was chemically treated with buffered chemical polishing and tested successfully in a collaboration between Helmholtz-Zentrum Dresden-Rossendorf and DESY. For several years a 1.3-GHz 1.6-cell resonator has been under study, which has been built and tested at DESY and elsewhere. For further studies and optimization the gun cavity needed to be electro-polished, which was conducted at DESY for the first time using vertical electro-polishing. The technical set-up for the vertical electro-polishing and high pressure rinsing as well as the processing parameters applied and the adaptation of the existing infrastructure to the 1.6-cell geometry at DESY are presented.
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MOPB118	Cleanliness and Vacuum Acceptance Tests for the UHV Cavity String of the XFEL Linac	452
	S. Berry, O. Napoly, B. Visentin CEA/DSM/IRFU, France C. Boulch, C. Cloué, C. Madec, T. Trublet CEA/IRFU, Gif-sur-Yvette, France D. Henning, L. Lilje, A. Matheisen, M. Schmökel DESY, Hamburg, Germany
	The main linac of the European XFEL will consist of 100 accelerator modules, i.e. 800 superconducting accelerator cavities operated at a design gradient of 23.6MV/m. In this context CEA-Saclay built an assembly facility designed to produce one module per week, ready to be tested at DESY. The facility overcame the foreseen production rate. We would like to highlight and discuss the critical fields: cleanliness and vacuum. A new assembly method to protect final assembly against particulates contamination has been implemented on the production line. Impact on cryomodule RF test is presented. Particle transport measurements on components used for the European XFEL accelerator module are presented. The results indicate that the nominal operation of the automated pumping and venting units will not lead to particle transport. Vacuum acceptance tests are of major interest: leak tests and residual gas analysis (RGA) are used to control the absence of air leak and contamination. The RGA specifications have been slightly relaxed to ensure the production rate.
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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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TUPB104	Series Production of BQU at DESY for the EU-XFEL Module Assembly at CEA Saclay	865
	B. van der Horst, M. Helmig, A. Matheisen, S. Saegebarth, M. Schalwat DESY, Hamburg, Germany
	Each of the 10³ XFEL modules foreseen for the EU-XFEL as well as the 3,9 GHZ injector module is equipped with a combination of beam position monitors, superconducting quadrupole and a gate valve connected to the beam position monitor. The subunits are prequalified by the different work package of the EU-XFEL collaboration and handover to the DESY cleanroom. These subunits are assembled in the DESY ISO 4 cleanroom to unit named BQU, quality controlled in respect of cleanliness and handover in status “ready for assembly in ISO 4 cleanroom” for string assembly to the ISO 4 cleanroom located at CEA France. Series production started with production sequences of one unit per week and needed to be accelerated up to five or six units per month (>=1.25 units per week) in beginning of 2015. Analysis of data taken during production and the optimization of work flow for higher production rates are presented.
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TUPB105	String Assembly for the EU-XFEL 3.9 GHz Module at DESY	869
	M. Schmökel, R. Bandelmann, A. Daniel, A. Matheisen, P. Schilling, B. van der Horst DESY, Hamburg, Germany R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy
	For the injector of the EU- XFEL one so-called 3.9 GHz module is required. This special module houses eight 3.9 GHz s.c. cavities, a beam position monitor and a quadrupole package. The cavities were fabricated and vertically tested as an in-kind contribution to the EU-XFEL by INFN Milano collaborators. The power couplers have been fabricated and conditioned by FNAL. The string assembly took place inside the ISO 4 cleanroom at DESY. A seven meter long alignment and assembly girder for this special string assembly has been designed and fabricated at DESY. The girder facilitates the assembly of the 3.9 GHz resonators with alternating power coupler orientation in ISO 4 cleanrooms. For redundancy and fast action on problems during string assembly, the DESY high pressure rinsing system (HPR) has been modified on the basis of the INFN Milano design for this 3.9 GHz application. The HPR has been qualified by four 3.9 GHz resonators, tested at INFN Milano. The integration of the cavities into Helium vessels, power coupler coupling factor and the power coupler assembly at DESY is qualified by one cavity that has been equipped with Helium tank and a power coupler and tested horizontally.
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THPB025	Exchange and Repair of Titanium Service Pipes for the EXFEL Series Cavities	1122
	M. Schalwat, S. Barbanotti, A. Daniel, H. Hintz, K. Jensch, A. Matheisen, S. Saegebarth, P. Schilling DESY, Hamburg, Germany A. Schmidt XFEL. EU, Hamburg, Germany
	Longitudinally-welded 72 mm ID service pipes (HSP) made from titanium grade 2 is used by the two suppliers of the helium tanks for the EU-XFEL accelerator. From the perspective of the PED DESY is legally designated as the manufacturer and is responsible for conformity to all relevant codes. During module assemblies at CEA Saclay the orbital welds of the interconnection bellows between cavities showed pores with dimensions outside the specifications set by DESY. These welds needed to be redone which caused a project delay of several months. The X-ray examination of the HSP showed that the pipes already exhibited many out-of- DESY spec pores in the longitudinal welds and were most likely the main cause of the problems in the orbital welds. It was decided to replace the extremities of the service pipes with seamless titanium tubes both on “naked” helium tanks as well as on tanks with cavities already welded in. At DESY more than 750 service pipes were exchanged over a period of 2 years. The qualification of the repair line according to PED regulation and the prove with RF test at 2 K that the repairs do not influence the high performance of the s.c. cavities were done.
	Poster THPB025 [0.172 MB]
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THPB032	Release Processes and Documentation Methods During Series Treatment of SRF Cavities for the European XFEL by Using an Engineering Data Management System	1154
	J. Iversen, J.A. Dammann, A. Matheisen, N. Steinhau-Kühl DESY, Hamburg, Germany
	For the European XFEL more than 800 superconducting cavities need to be treated. At least 65 quality documents per cavity have to be emitted and transferred to DESY by the vendor; two acceptance levels must be passed successfully to release a cavity for transportation to DESY. All quality documents, non-conformity reports and acceptance levels are automatically processed by using DESY’s Engineering Data Management System (EDMS). We summarize documentation methods, document transfer procedures, review and release processes; we describe the exchange of process information between customer and vendor; and report about experiences.
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THPB056	SRF Gun Cavity R&D at DESY	1231
	D. Kostin, C. Albrecht, A. Brinkmann, Th. Buettner, J. Eschke, T. Feldmann, A. Gössel, D. Klinke, A. Matheisen, W.-D. Möller, D. Reschke, M. Schmökel, J.K. Sekutowicz, W. Singer, X. Singer, N. Steinhau-Kühl, J. Ziegler, B. van der Horst DESY, Hamburg, Germany M. Barlak, J.A. Lorkiewicz, R. Nietubyć NCBJ, Świerk/Otwock, Poland
	SRF Gun Cavity is an ongoing accelerator R&D project at DESY, being developed since several years. Currently several SRF Gun cavity prototypes were simulated, built and tested in our Lab and elsewhere. Lately the 1.6 cells Pb thin film cathode niobium cavity was tested in a vertical cryostat with a different cathode plug configurations. Cathode plug design was improved, as well as SRF Gun Cavity cleaning procedures. Results of the last cavity performance tests are presented and discussed.
	Poster THPB056 [1.257 MB]
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Paper

Title

Page

Experiences on Retreatment of EU-XFEL Series Cavities at DESY

296

A. Matheisen, N. Krupka, S. Saegebarth, P. Schilling, N. Steinhau-Kühl, B. van der Horst
DESY, Hamburg, Germany

For the European XFEL (EU-XFEL), two industrial companies are responsible for the manufacture and surface preparation of the eight hundred superconducting cavities. The companies had to strictly follow the XFEL specification and document all production and preparation steps. No performance guaranties were required. Each cavity delivered by industry to DESY is tested in a vertical test at 2K. Resonators not reaching the performances defined for application at the EU-XFEL linear accelerator modules or showing leakage during cold RF tests have undergone a subsequent retreatment at DESY. Nearly 20% of the cavity production required retreatment, most of them by an additional high pressure rinsing. Some cavities received additional chemical treatment by BCP flash after the initial HPR did not cure the problem. The analysis of retreatments and quality control data available from the retreatment sequences and the workflow of retreatment will be presented.

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MOPB076

Horizontal RF Test of a Fully Equipped 3.9 GHz Cavity for the European XFEL in the DESY AMTF

301

C.G. Maiano, C. Albrecht, R. Bospflug, J. Branlard, Ł. Butkowski, T. Delfs, J. Eschke, A. Gössel, F. Hoffmann, M. Hüning, K. Jensch, R. Jonas, R. Klos, D. Kostin, W. Maschmann, A. Matheisen, U. Mavrič, W.-D. Möller, C. Müller, K. Mueller, B. Petersen, P. Pierini, J. Rothenburg, O. Sawlanski, M. Schmökel, A.A. Sulimov, E. Vogel
DESY, Hamburg, Germany
A. Bosotti, M. Moretti, R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy
E.R. Harms
Fermilab, Batavia, Illinois, USA
C.R. Montiel
ANL, Argonne, Illinois, USA
S. Pivovarov
BINP SB RAS, Novosibirsk, Russia

In order to validate the cavity package concept before the module preparation for the European XFEL Injector, one 3.9 GHz cavity, complete with magnetic shielding, power coupler and frequency tuner was tested in a specially designed single cavity cryomodule in one of the caves of the DESY Accelerator Module Test Facility (AMTF). The cavity was tested in high power pulsed operation up to the quench limit of 24 MV/m, above the vertical test qualifications and all subsystems under test (coupler, tuner, waveguide tuners, LLRF system) were qualified to design performances.

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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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MOPB090

Analysis of Degraded Cavities in Prototype Modules for the European XFEL

355

S. Aderhold
Fermilab, Batavia, Illinois, USA
S. Aderhold, D. Kostin, A. Matheisen, A. Navitski, D. Reschke
DESY, Hamburg, Germany

In-between the fabrication and the operation in an accelerator the performance of superconducting RF cavities is typically tested several times. Although the assembly is done under very controlled conditions in a clean room, it is observed from time to time that a cavity with good performance in the vertical acceptance test shows deteriorated performance in the accelerator module afterwards. This work presents the analysis of several such cavities that have been disassembled from modules of the prototype phase for the European XFEL for detailed investigation like additional rf tests, optical inspection and replica.

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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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MOPB102

Comments on Electropolishing at Ettore Zanon SpA at the End of EXFEL Production

394

M. Rizzi, G. Corniani
Ettore Zanon S.p.A., Schio, Italy
A. Matheisen
DESY, Hamburg, Germany
P. Michelato
INFN/LASA, Segrate (MI), Italy

In 2013 a new horizontal Electropolishing facility was developed and implemented by Ettore Zanon SpA (EZ) for the treatment of cavities for the European XFEL series production. More than 300 cavities have been treated. Electropolishing has been used for two applications: bulk removal and recovering of cavities with surface defects. Treatment settings have been analysed and compared with cavities performances to verify possible influences of the various parameters. Main parameters considered are treatment time, voltage and current, that together define average thickness removal. We present here the results of these investigation. The facility and process in use are also presented, together with possible next upgrade of the system, facing the new production of cavities for the LCLSII project.

Poster MOPB102 [1.535 MB]

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MOPB103

Vertical Electro-Polishing at DESY of a 1.3 GHz Gun Cavity for CW Application

399

N. Steinhau-Kühl, R. Bandelmann, D. Kostin, A. Matheisen, M. Schmökel, J.K. Sekutowicz
DESY, Hamburg, Germany

Superconducting gun cavities for cw operation in accelerators are under study. In 2003 a three-and-a-half cell gun cavity was chemically treated with buffered chemical polishing and tested successfully in a collaboration between Helmholtz-Zentrum Dresden-Rossendorf and DESY. For several years a 1.3-GHz 1.6-cell resonator has been under study, which has been built and tested at DESY and elsewhere. For further studies and optimization the gun cavity needed to be electro-polished, which was conducted at DESY for the first time using vertical electro-polishing. The technical set-up for the vertical electro-polishing and high pressure rinsing as well as the processing parameters applied and the adaptation of the existing infrastructure to the 1.6-cell geometry at DESY are presented.

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MOPB118

Cleanliness and Vacuum Acceptance Tests for the UHV Cavity String of the XFEL Linac

452

S. Berry, O. Napoly, B. Visentin
CEA/DSM/IRFU, France
C. Boulch, C. Cloué, C. Madec, T. Trublet
CEA/IRFU, Gif-sur-Yvette, France
D. Henning, L. Lilje, A. Matheisen, M. Schmökel
DESY, Hamburg, Germany

The main linac of the European XFEL will consist of 100 accelerator modules, i.e. 800 superconducting accelerator cavities operated at a design gradient of 23.6MV/m. In this context CEA-Saclay built an assembly facility designed to produce one module per week, ready to be tested at DESY. The facility overcame the foreseen production rate. We would like to highlight and discuss the critical fields: cleanliness and vacuum. A new assembly method to protect final assembly against particulates contamination has been implemented on the production line. Impact on cryomodule RF test is presented. Particle transport measurements on components used for the European XFEL accelerator module are presented. The results indicate that the nominal operation of the automated pumping and venting units will not lead to particle transport. Vacuum acceptance tests are of major interest: leak tests and residual gas analysis (RGA) are used to control the absence of air leak and contamination. The RGA specifications have been slightly relaxed to ensure the production rate.

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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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TUPB104

Series Production of BQU at DESY for the EU-XFEL Module Assembly at CEA Saclay

865

B. van der Horst, M. Helmig, A. Matheisen, S. Saegebarth, M. Schalwat
DESY, Hamburg, Germany

Each of the 10³ XFEL modules foreseen for the EU-XFEL as well as the 3,9 GHZ injector module is equipped with a combination of beam position monitors, superconducting quadrupole and a gate valve connected to the beam position monitor. The subunits are prequalified by the different work package of the EU-XFEL collaboration and handover to the DESY cleanroom. These subunits are assembled in the DESY ISO 4 cleanroom to unit named BQU, quality controlled in respect of cleanliness and handover in status “ready for assembly in ISO 4 cleanroom” for string assembly to the ISO 4 cleanroom located at CEA France. Series production started with production sequences of one unit per week and needed to be accelerated up to five or six units per month (>=1.25 units per week) in beginning of 2015. Analysis of data taken during production and the optimization of work flow for higher production rates are presented.

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TUPB105

String Assembly for the EU-XFEL 3.9 GHz Module at DESY

869

M. Schmökel, R. Bandelmann, A. Daniel, A. Matheisen, P. Schilling, B. van der Horst
DESY, Hamburg, Germany
R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy

For the injector of the EU- XFEL one so-called 3.9 GHz module is required. This special module houses eight 3.9 GHz s.c. cavities, a beam position monitor and a quadrupole package. The cavities were fabricated and vertically tested as an in-kind contribution to the EU-XFEL by INFN Milano collaborators. The power couplers have been fabricated and conditioned by FNAL. The string assembly took place inside the ISO 4 cleanroom at DESY. A seven meter long alignment and assembly girder for this special string assembly has been designed and fabricated at DESY. The girder facilitates the assembly of the 3.9 GHz resonators with alternating power coupler orientation in ISO 4 cleanrooms. For redundancy and fast action on problems during string assembly, the DESY high pressure rinsing system (HPR) has been modified on the basis of the INFN Milano design for this 3.9 GHz application. The HPR has been qualified by four 3.9 GHz resonators, tested at INFN Milano. The integration of the cavities into Helium vessels, power coupler coupling factor and the power coupler assembly at DESY is qualified by one cavity that has been equipped with Helium tank and a power coupler and tested horizontally.

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THPB025

Exchange and Repair of Titanium Service Pipes for the EXFEL Series Cavities

1122

M. Schalwat, S. Barbanotti, A. Daniel, H. Hintz, K. Jensch, A. Matheisen, S. Saegebarth, P. Schilling
DESY, Hamburg, Germany
A. Schmidt
XFEL. EU, Hamburg, Germany

Longitudinally-welded 72 mm ID service pipes (HSP) made from titanium grade 2 is used by the two suppliers of the helium tanks for the EU-XFEL accelerator. From the perspective of the PED DESY is legally designated as the manufacturer and is responsible for conformity to all relevant codes. During module assemblies at CEA Saclay the orbital welds of the interconnection bellows between cavities showed pores with dimensions outside the specifications set by DESY. These welds needed to be redone which caused a project delay of several months. The X-ray examination of the HSP showed that the pipes already exhibited many out-of- DESY spec pores in the longitudinal welds and were most likely the main cause of the problems in the orbital welds. It was decided to replace the extremities of the service pipes with seamless titanium tubes both on “naked” helium tanks as well as on tanks with cavities already welded in. At DESY more than 750 service pipes were exchanged over a period of 2 years. The qualification of the repair line according to PED regulation and the prove with RF test at 2 K that the repairs do not influence the high performance of the s.c. cavities were done.

Poster THPB025 [0.172 MB]

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THPB032

Release Processes and Documentation Methods During Series Treatment of SRF Cavities for the European XFEL by Using an Engineering Data Management System

1154

J. Iversen, J.A. Dammann, A. Matheisen, N. Steinhau-Kühl
DESY, Hamburg, Germany

For the European XFEL more than 800 superconducting cavities need to be treated. At least 65 quality documents per cavity have to be emitted and transferred to DESY by the vendor; two acceptance levels must be passed successfully to release a cavity for transportation to DESY. All quality documents, non-conformity reports and acceptance levels are automatically processed by using DESY’s Engineering Data Management System (EDMS). We summarize documentation methods, document transfer procedures, review and release processes; we describe the exchange of process information between customer and vendor; and report about experiences.

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THPB056

SRF Gun Cavity R&D at DESY

1231

D. Kostin, C. Albrecht, A. Brinkmann, Th. Buettner, J. Eschke, T. Feldmann, A. Gössel, D. Klinke, A. Matheisen, W.-D. Möller, D. Reschke, M. Schmökel, J.K. Sekutowicz, W. Singer, X. Singer, N. Steinhau-Kühl, J. Ziegler, B. van der Horst
DESY, Hamburg, Germany
M. Barlak, J.A. Lorkiewicz, R. Nietubyć
NCBJ, Świerk/Otwock, Poland

SRF Gun Cavity is an ongoing accelerator R&D project at DESY, being developed since several years. Currently several SRF Gun cavity prototypes were simulated, built and tested in our Lab and elsewhere. Lately the 1.6 cells Pb thin film cathode niobium cavity was tested in a vertical cryostat with a different cathode plug configurations. Cathode plug design was improved, as well as SRF Gun Cavity cleaning procedures. Results of the last cavity performance tests are presented and discussed.

Poster THPB056 [1.257 MB]

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