SRF2017 - List of Keywords (ISOL)

Paper	Title	Other Keywords	Page
MOPB109	LCLS-II Cryomodule Transport System Testing	ion, cavity, vacuum, cryomodule	317
	N.A. Huque, E. Daly JLab, Newport News, Virginia, USA M.W. McGee Fermilab, Batavia, Illinois, USA
	The Cryomodules (CM) for the Linear Coherent Light Source II (LCLS-II) will be shipped to SLAC (Menlo Park, California) from JLab (Newport News, Virginia) and FNAL (Batavia, Illinois). A transportation system has been designed and built to safely transport the CMs over the road. It uses an array of helical isolator springs to attenuate shocks on the CM to below 1.5g in all directions. The system rides on trailers equipped with Air-Ride suspension, which attenuates vibration loads. The prototype LCLS-II CM (pCM) was driven 750 miles to test the transport system; shock loggers recorded the shock attenuation on the pCM and vacuum gauges were used to detect any compromises in beamline vacuum. Alignment measurements were taken before and after the trip to check whether cavity positions had shifted beyond the ± 0.2mm spec. Passband frequencies and cavity gradients were measured at 2K at the Cryomodule Test Facility (CMTF) at JLab to identify any degradation of CM performance after transportation. The transport system was found to have safely carried the CM and is cleared to begin shipments from JLab and FNAL to SLAC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB109
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TUXAA02	HIE Isolde Cavity Production & Cryomodule Commissioning, Lessons Learned	ion, cavity, cryomodule, linac	338
	W. Venturini Delsolaro, K. Artoos, O. Brunner, O. Capatina, K.M. Dr. Schirm, Y. Kadi, Y. Leclercq, A. Miyazaki, E. Montesinos, V. Parma, G.J. Rosaz, A. Sublet, S. Teixeira Lopez, M. Therasse, L.R. Williams CERN, Geneva, Switzerland
	The lessons learned during the HIE Isolde Cavity Production, the Cryo Module Assembly and Commissioning will be presented
	Slides TUXAA02 [8.191 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUXAA02
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TUYBA02	Thermal Boundary Resistance Model and Defect Statistical Distribution in Nb/Cu Cavities	ion, cavity, interface, feedback	374
	R. Vaglio UniNa, Napoli, Italy V. Palmieri INFN/LNL, Legnaro (PD), Italy
	The ‘Q-slope' problem strongly limits the application of niobium thin film sputtered cavities in high field accelerators. Here we consider the hypothesis that the Q-slope is related to local enhanced of the thermal boundary resistance at the Nb/Cu interface, due to poor thermal contact between film and substrate. We introduce a simple model that directly connects the Q versus Eacc curves to the distribution function f(RNb/Cu) of RNb/Cu thermal contact at the Nb/Cu interface over the cavity surface. Starting from the experimental curves, using inverse problem methods, we deduce the distribution functions generating those curves. The technique has been applied to cavities by different groups, including LNL/INFN and ISOLDE/CERN. In all cases to explain the data it is sufficient to assume that only a small fraction of the film over the cavity surface is in poor thermal contact with the substrate. The distribution functions typically follow a simple power-law statistical distribution and are temperature independent. The full analysis supports the hypothesis that the main origin of the Q-slope in thin film cavities is indeed related to bad adhesion at the Nb/Cu interface.
	Slides TUYBA02 [0.988 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUYBA02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB056	Study on a Low Beta High Current Taper Type Superconducting Half Wave Resonator for BISOL	cavity, ion, simulation, experiment	516
	F. Zhu, M. Chen, L.W. Feng, S.W. Quan, F. Wang, H.T.X. Zhong PKU, Beijing, People's Republic of China
	Funding: Work supported by National Basic Research Project (No. 2014CB845504) Beijing isotope separation on line type rare ion beam facility (BISOL) for both basic science and applications is a project proposed by China Institute of Atomic Energy and Peking University. Deuteron driver accelerator of BISOL would adopt superconducting half wave resonator (HWR) with low beta and high current. For pre-research of BISOL, a β=0.09 162.5 MHz taper type HWR cavity has been designed for accelerating deuteron beam with several tens of mA. The Design, fabrication, post-processing and room temperature RF measurement of the HWR cavity will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB056
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TUPB078	SUBU Characterisation: Bath Fluid Dynamics vs Etching Rate	ion, cavity, simulation, software	575
	A. Perez Rodriguez, L.M.A. Ferreira, A. Sublet CERN, Geneva, Switzerland
	The chemical polishing bath SUBU is widely used at CERN to prepare copper RF cavities surfaces before niobium thin film coating; examples are HIE-ISOLDE, LHC and future FCC accelerating cavities. The performance of the polishing process is affected by bath temperature and fluid dynamics. As part of on-going activities to characterise SUBU, the actual study was done to identify a correlation between the etching rate and physical parameters linked to the bath fluid dynamics. A first approach was made using experimental data from a simplified model setup, transposing them via numerical simulation to a real cavity geometry and verifying the agreement with an experiment in a real size (HIE-ISOLDE) mock-up. In a second approach to improve the accuracy of the calculation, the relation of the measured local etching rates, extracted from the mock-up, to flow dynamics quantities extracted from simulation was investigated. As a result, a correlation between the local etching rate and the turbulence kinetic energy was obtained. This correlation can be exploited to improve the polishing tools and so optimise the current process, as well as to predict the etching rate in other cavity geometries.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB078
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEYA03	A Seamless Quarter-wave Resonator for HIE-ISOLDE	ion, cavity, linac, cryomodule	686
	S. Teixeira Lopez, M.A. Fraser, M. Garlaschè, T. Mikkola, A. Miyazaki, A. Sublet, W. Venturini Delsolaro CERN, Geneva, Switzerland
	The superconducting linac booster for the HIE ISOLDE project, in operation at CERN, is based on NB/Cu coated Quarter Wave Resonators. The performance of the series cavities has been limited by defects in the copper substrates close to the EB weld. A novel cavity design has been developed and prototyped, in order to make it possible manufacturing of the resonators by machining them from the bulk, without any weld. The RF design was optimized for the customary figures of merit, and fully integrated in the HIE ISOLDE cryomodule. Mechanical tolerances were assessed in relation to the available range of pre tuning, and demonstrated on a dummy prototype. Beam dynamics simulations were carried out to check the effects on the beams when the new cavities will be installed in the high energy end of the linac. The presentation will cover the design and the first experimental results of the first Nb/Cu seamless QWR for HIE ISOLDE.
	Slides WEYA03 [5.262 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-WEYA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPB048	Double Cathode Configuration for the Nb Coating of HIE-ISOLDE Cavities	ion, cathode, cavity, simulation	854
	A. Awais NCP, Islamabad, Pakistan A. Awais, A.J.G. Lunt, G.J. Rosaz, A. Sublet, M. Taborelli CERN, Geneva, Switzerland
	The Quarter Wave Resonator (QWR) cavities for HIE-ISOLDE project at CERN have entered their ending phase of production. Some R&D is still required to improve the uniformity of the Nb layer thickness on the cavity surface. In order to improve this behaviour one approach which has been proposed is to replace the single cathode with a double cathode and test the suitability of different deposition techniques. With this change it is possible to control the plasma and power distribution separately for the inner and outer part of cavity and thereby potentially improve film uniformity throughout the cavity and coating duration. In this study a comparison between the deposition rates obtained using a single cathode and a double cathode using Direct Current (DC)-bias diode sputtering, DC-magnetron sputtering (DCMS) and Pulsed DC-magnetron sputtering (PDCMS) is presented. The morphology of the thin film samples were compared using Focused Ion Beam (FIB) cross section milling and Scanning Electron Microscopy (SEM) analysis.
	Poster THPB048 [3.715 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB048
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPB109

LCLS-II Cryomodule Transport System Testing

ion, cavity, vacuum, cryomodule

317

N.A. Huque, E. Daly
JLab, Newport News, Virginia, USA
M.W. McGee
Fermilab, Batavia, Illinois, USA

The Cryomodules (CM) for the Linear Coherent Light Source II (LCLS-II) will be shipped to SLAC (Menlo Park, California) from JLab (Newport News, Virginia) and FNAL (Batavia, Illinois). A transportation system has been designed and built to safely transport the CMs over the road. It uses an array of helical isolator springs to attenuate shocks on the CM to below 1.5g in all directions. The system rides on trailers equipped with Air-Ride suspension, which attenuates vibration loads. The prototype LCLS-II CM (pCM) was driven 750 miles to test the transport system; shock loggers recorded the shock attenuation on the pCM and vacuum gauges were used to detect any compromises in beamline vacuum. Alignment measurements were taken before and after the trip to check whether cavity positions had shifted beyond the ± 0.2mm spec. Passband frequencies and cavity gradients were measured at 2K at the Cryomodule Test Facility (CMTF) at JLab to identify any degradation of CM performance after transportation. The transport system was found to have safely carried the CM and is cleared to begin shipments from JLab and FNAL to SLAC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB109

Export •

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

TUXAA02

HIE Isolde Cavity Production & Cryomodule Commissioning, Lessons Learned

ion, cavity, cryomodule, linac

338

W. Venturini Delsolaro, K. Artoos, O. Brunner, O. Capatina, K.M. Dr. Schirm, Y. Kadi, Y. Leclercq, A. Miyazaki, E. Montesinos, V. Parma, G.J. Rosaz, A. Sublet, S. Teixeira Lopez, M. Therasse, L.R. Williams
CERN, Geneva, Switzerland

The lessons learned during the HIE Isolde Cavity Production, the Cryo Module Assembly and Commissioning will be presented

Slides TUXAA02 [8.191 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUXAA02

Export •

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

TUYBA02

Thermal Boundary Resistance Model and Defect Statistical Distribution in Nb/Cu Cavities

ion, cavity, interface, feedback

374

R. Vaglio
UniNa, Napoli, Italy
V. Palmieri
INFN/LNL, Legnaro (PD), Italy

The ‘Q-slope' problem strongly limits the application of niobium thin film sputtered cavities in high field accelerators. Here we consider the hypothesis that the Q-slope is related to local enhanced of the thermal boundary resistance at the Nb/Cu interface, due to poor thermal contact between film and substrate. We introduce a simple model that directly connects the Q versus Eacc curves to the distribution function f(RNb/Cu) of RNb/Cu thermal contact at the Nb/Cu interface over the cavity surface. Starting from the experimental curves, using inverse problem methods, we deduce the distribution functions generating those curves. The technique has been applied to cavities by different groups, including LNL/INFN and ISOLDE/CERN. In all cases to explain the data it is sufficient to assume that only a small fraction of the film over the cavity surface is in poor thermal contact with the substrate. The distribution functions typically follow a simple power-law statistical distribution and are temperature independent. The full analysis supports the hypothesis that the main origin of the Q-slope in thin film cavities is indeed related to bad adhesion at the Nb/Cu interface.

Slides TUYBA02 [0.988 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUYBA02

Export •

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

TUPB056

Study on a Low Beta High Current Taper Type Superconducting Half Wave Resonator for BISOL

cavity, ion, simulation, experiment

516

F. Zhu, M. Chen, L.W. Feng, S.W. Quan, F. Wang, H.T.X. Zhong
PKU, Beijing, People's Republic of China

Funding: Work supported by National Basic Research Project (No. 2014CB845504)
Beijing isotope separation on line type rare ion beam facility (BISOL) for both basic science and applications is a project proposed by China Institute of Atomic Energy and Peking University. Deuteron driver accelerator of BISOL would adopt superconducting half wave resonator (HWR) with low beta and high current. For pre-research of BISOL, a β=0.09 162.5 MHz taper type HWR cavity has been designed for accelerating deuteron beam with several tens of mA. The Design, fabrication, post-processing and room temperature RF measurement of the HWR cavity will be presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB056

Export •

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

TUPB078

SUBU Characterisation: Bath Fluid Dynamics vs Etching Rate

ion, cavity, simulation, software

575

A. Perez Rodriguez, L.M.A. Ferreira, A. Sublet
CERN, Geneva, Switzerland

The chemical polishing bath SUBU is widely used at CERN to prepare copper RF cavities surfaces before niobium thin film coating; examples are HIE-ISOLDE, LHC and future FCC accelerating cavities. The performance of the polishing process is affected by bath temperature and fluid dynamics. As part of on-going activities to characterise SUBU, the actual study was done to identify a correlation between the etching rate and physical parameters linked to the bath fluid dynamics. A first approach was made using experimental data from a simplified model setup, transposing them via numerical simulation to a real cavity geometry and verifying the agreement with an experiment in a real size (HIE-ISOLDE) mock-up. In a second approach to improve the accuracy of the calculation, the relation of the measured local etching rates, extracted from the mock-up, to flow dynamics quantities extracted from simulation was investigated. As a result, a correlation between the local etching rate and the turbulence kinetic energy was obtained. This correlation can be exploited to improve the polishing tools and so optimise the current process, as well as to predict the etching rate in other cavity geometries.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB078

Export •

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

WEYA03

A Seamless Quarter-wave Resonator for HIE-ISOLDE

ion, cavity, linac, cryomodule

686

S. Teixeira Lopez, M.A. Fraser, M. Garlaschè, T. Mikkola, A. Miyazaki, A. Sublet, W. Venturini Delsolaro
CERN, Geneva, Switzerland

The superconducting linac booster for the HIE ISOLDE project, in operation at CERN, is based on NB/Cu coated Quarter Wave Resonators. The performance of the series cavities has been limited by defects in the copper substrates close to the EB weld. A novel cavity design has been developed and prototyped, in order to make it possible manufacturing of the resonators by machining them from the bulk, without any weld. The RF design was optimized for the customary figures of merit, and fully integrated in the HIE ISOLDE cryomodule. Mechanical tolerances were assessed in relation to the available range of pre tuning, and demonstrated on a dummy prototype. Beam dynamics simulations were carried out to check the effects on the beams when the new cavities will be installed in the high energy end of the linac. The presentation will cover the design and the first experimental results of the first Nb/Cu seamless QWR for HIE ISOLDE.

Slides WEYA03 [5.262 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-WEYA03

Export •

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

THPB048

Double Cathode Configuration for the Nb Coating of HIE-ISOLDE Cavities

ion, cathode, cavity, simulation

854

A. Awais
NCP, Islamabad, Pakistan
A. Awais, A.J.G. Lunt, G.J. Rosaz, A. Sublet, M. Taborelli
CERN, Geneva, Switzerland

The Quarter Wave Resonator (QWR) cavities for HIE-ISOLDE project at CERN have entered their ending phase of production. Some R&D is still required to improve the uniformity of the Nb layer thickness on the cavity surface. In order to improve this behaviour one approach which has been proposed is to replace the single cathode with a double cathode and test the suitability of different deposition techniques. With this change it is possible to control the plasma and power distribution separately for the inner and outer part of cavity and thereby potentially improve film uniformity throughout the cavity and coating duration. In this study a comparison between the deposition rates obtained using a single cathode and a double cathode using Direct Current (DC)-bias diode sputtering, DC-magnetron sputtering (DCMS) and Pulsed DC-magnetron sputtering (PDCMS) is presented. The morphology of the thin film samples were compared using Focused Ion Beam (FIB) cross section milling and Scanning Electron Microscopy (SEM) analysis.

Poster THPB048 [3.715 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB048

Export •

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