SRF2017 - List of Keywords (shielding)

Paper	Title	Other Keywords	Page
MOPB010	Design of the 2×4-cell Superconducting Cryomodule for the Free-electron Laser	ion, cryomodule, cavity, radiation	67
	X. Luo, C.L. Lao, M. Li, L.J. Shan, X.M. Shen, H. Wang, X. Yang, K. Zhou CAEP/IAE, Mianyang, Sichuan, People's Republic of China X.Y. Lu, S.W. Quan, F. Wang PKU, Beijing, People's Republic of China
	A 2×4-cell superconducting linac module for the THz-FEL facility has been developed at the China Academy of Engineering Physics, which is expected to provide 6~8 MeV quasi-CW electron beams with an average current of 1~5 mA. The design of the cryomodule is presented in this paper. The dynamic and static heat load have been evaluated to reasonable level. The temperature distribution inside the cryomodule has been optimized by simulation, as well as mechanical structure and the magnetic shielding.
	Poster MOPB010 [1.019 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB010
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MOPB044	Magnetic Hygiene Control on LCLS-II Cryomodules Fabricated at JLab	ion, cavity, cryomodule, controls	153
	G. Cheng, E. Daly, G.K. Davis, J.F. Fischer, N.A. Huque, R.A. Legg, H. Park, K.M. Wilson, L. Zhao JLab, Newport News, Virginia, USA
	Funding: U.S. DOE Contract No. DE-AC05-06OR23177 and the LCLS-II project. Jefferson Lab (JLab) is in collaboration with Fermi Na-tional Accelerator Laboratory (Fermilab) to build 18 cryomodules to install at the SLAC National Accelerator Laboratory's tunnel as part of the Linac Coherent Light Source upgrade project (LCLS-II). Each LCLS-II cry-omodule hosts 8 superconducting niobium cavities that adopt the nitrogen doping technique, which aims to en-hance the cavity quality factor Qo to reduce the consumption of liquid helium used to cool down the cavities. It is known that the Qo of niobium cavities is affected by cavity surface magnetic field. Traditionally, magnetic shields made of high magnetic permeability mu-metals are employed as a passive shielding of the ambient magnetic fluxes. During the LCLS-II cryomodule development, magnetic hygiene control that includes magnetic shielding and demagnetization of parts and the whole-machine is implemented. JLab and Fermilab worked closely on developing magnetic hygiene control procedures, identifying relevant tools, investigating causes of magnetization, magnetic field monitoring, etc. This paper focuses on JLab's experiences with LCLS-II cryomodule magnetic hygiene control during its fabrication. Authored by Jefferson Science Associates, LLC. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for Government purposes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB044
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MOPB089	Characterisation of Magnetic Shielding Material for HL-LHC Crab Cavities	ion, cavity, cryogenics, ECR	273
	K. Eiler, P. Arpaia, M.C.L. Buzio, O. Capatina, S.A.E. Langeslag, A. Parrella CERN, Geneva, Switzerland P. Arpaia, A. Parrella Naples University Federico II, Science and Technology Pole, Napoli, Italy A. Parrella IT, Lisboa, Portugal N. Templeton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: CERN, 1211 Geneva 23 To guarantee optimum performance, the crab cavities for the high-luminosity upgrade of CERN's LHC need to be shielded from external magnetic fields. Consequently, they will be enclosed by two layers of magnetic shielding, of which the inner is immersed in superfluid helium at 2 K. A Ni-based high-permeability material with a tailored composition and a designated heat treatment is applied. Its magnetic properties at cryogenic temperature are however not yet fully assessed. Especially the effect of deformation on magnetic properties has not been thoroughly investigated, however strain effects may have severe consequences. A magnetic measurement set-up has been developed, and the magnetic permeability at room temperature and at cryogenic temperatures is evaluated, showing that the maximum relative permeability at 4 K exceeds the design criteria of 100, 000. Measurements of the magnetic permeability after introduction of uniaxial plastic deformation between 0% and 3% are conducted by means of an Epstein frame. Results show that deformation induces significant decrease of the magnetic performance, underlining that particular care must be taken during all stages of handling and operation. *konrad.eiler@cern.ch
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB089
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MOPB090	Sub-micro-Tesla Magnetic Shielding Design for Cryomodules in the High-gradient Program at CERN	ion, cavity, cryomodule, simulation	278
	S. Papadopoulos, L. Dassa, F. Gerigk, F. Pillon, S. Ramberger, P. Yilmazer CERN, Geneva, Switzerland J. Dequaire Intitek, Lyon, France
	In the framework of the High-Gradient R\&D program at CERN a cryomodule, consisting of four superconducting 5-cell cavities, has been designed. In order to reduce flux trapping in the surface of the superconductor and to minimize Q degradation during a quench, highly effective magnetic shielding is needed. The solution proposed includes cold and warm passive shielding enhanced by four compensating coils. In this paper the magneto-static simulation results are presented illustrating different design considerations that led to a final design. Finally the shielding ability of the vacuum vessel is investigated experimentally through ambient magnetic field measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB090
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TUPB099	Vertical Test System for Superconducting RF Cavities at Peking University	ion, cavity, radiation, controls	631
	D. Zhou, J.E. Chen, W. Cheng, L.W. Feng, J.K. Hao, L. Lin, K.X. Liu, S.W. Quan, F. Wang, H.M. Xie, F. Zhu, D.H. Zhuang PKU, Beijing, People's Republic of China
	A new vertical test system (VTS) for superconducting RF cavities has been designed and constructed at Peking University. This facility is designed to operate at a temperature of 2K and with pumping speed of 10g/s for helium gas at 30 mbar. In this paper, we present the structure design, modification of 2K system, ambient magnetic field and radiation shielding, LLRF and the test run of this VTS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB099
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Paper

Title

Other Keywords

Page

MOPB010

Design of the 2×4-cell Superconducting Cryomodule for the Free-electron Laser

ion, cryomodule, cavity, radiation

67

X. Luo, C.L. Lao, M. Li, L.J. Shan, X.M. Shen, H. Wang, X. Yang, K. Zhou
CAEP/IAE, Mianyang, Sichuan, People's Republic of China
X.Y. Lu, S.W. Quan, F. Wang
PKU, Beijing, People's Republic of China

A 2×4-cell superconducting linac module for the THz-FEL facility has been developed at the China Academy of Engineering Physics, which is expected to provide 6~8 MeV quasi-CW electron beams with an average current of 1~5 mA. The design of the cryomodule is presented in this paper. The dynamic and static heat load have been evaluated to reasonable level. The temperature distribution inside the cryomodule has been optimized by simulation, as well as mechanical structure and the magnetic shielding.

Poster MOPB010 [1.019 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB010

Export •

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

MOPB044

Magnetic Hygiene Control on LCLS-II Cryomodules Fabricated at JLab

ion, cavity, cryomodule, controls

153

G. Cheng, E. Daly, G.K. Davis, J.F. Fischer, N.A. Huque, R.A. Legg, H. Park, K.M. Wilson, L. Zhao
JLab, Newport News, Virginia, USA

Funding: U.S. DOE Contract No. DE-AC05-06OR23177 and the LCLS-II project.
Jefferson Lab (JLab) is in collaboration with Fermi Na-tional Accelerator Laboratory (Fermilab) to build 18 cryomodules to install at the SLAC National Accelerator Laboratory's tunnel as part of the Linac Coherent Light Source upgrade project (LCLS-II). Each LCLS-II cry-omodule hosts 8 superconducting niobium cavities that adopt the nitrogen doping technique, which aims to en-hance the cavity quality factor Qo to reduce the consumption of liquid helium used to cool down the cavities. It is known that the Qo of niobium cavities is affected by cavity surface magnetic field. Traditionally, magnetic shields made of high magnetic permeability mu-metals are employed as a passive shielding of the ambient magnetic fluxes. During the LCLS-II cryomodule development, magnetic hygiene control that includes magnetic shielding and demagnetization of parts and the whole-machine is implemented. JLab and Fermilab worked closely on developing magnetic hygiene control procedures, identifying relevant tools, investigating causes of magnetization, magnetic field monitoring, etc. This paper focuses on JLab's experiences with LCLS-II cryomodule magnetic hygiene control during its fabrication.
Authored by Jefferson Science Associates, LLC. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for Government purposes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB044

Export •

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

MOPB089

Characterisation of Magnetic Shielding Material for HL-LHC Crab Cavities

ion, cavity, cryogenics, ECR

273

K. Eiler, P. Arpaia, M.C.L. Buzio, O. Capatina, S.A.E. Langeslag, A. Parrella
CERN, Geneva, Switzerland
P. Arpaia, A. Parrella
Naples University Federico II, Science and Technology Pole, Napoli, Italy
A. Parrella
IT, Lisboa, Portugal
N. Templeton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Funding: CERN, 1211 Geneva 23
To guarantee optimum performance, the crab cavities for the high-luminosity upgrade of CERN's LHC need to be shielded from external magnetic fields. Consequently, they will be enclosed by two layers of magnetic shielding, of which the inner is immersed in superfluid helium at 2 K. A Ni-based high-permeability material with a tailored composition and a designated heat treatment is applied. Its magnetic properties at cryogenic temperature are however not yet fully assessed. Especially the effect of deformation on magnetic properties has not been thoroughly investigated, however strain effects may have severe consequences. A magnetic measurement set-up has been developed, and the magnetic permeability at room temperature and at cryogenic temperatures is evaluated, showing that the maximum relative permeability at 4 K exceeds the design criteria of 100, 000. Measurements of the magnetic permeability after introduction of uniaxial plastic deformation between 0% and 3% are conducted by means of an Epstein frame. Results show that deformation induces significant decrease of the magnetic performance, underlining that particular care must be taken during all stages of handling and operation.
*konrad.eiler@cern.ch

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB089

Export •

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

MOPB090

Sub-micro-Tesla Magnetic Shielding Design for Cryomodules in the High-gradient Program at CERN

ion, cavity, cryomodule, simulation

278

S. Papadopoulos, L. Dassa, F. Gerigk, F. Pillon, S. Ramberger, P. Yilmazer
CERN, Geneva, Switzerland
J. Dequaire
Intitek, Lyon, France

In the framework of the High-Gradient R\&D program at CERN a cryomodule, consisting of four superconducting 5-cell cavities, has been designed. In order to reduce flux trapping in the surface of the superconductor and to minimize Q degradation during a quench, highly effective magnetic shielding is needed. The solution proposed includes cold and warm passive shielding enhanced by four compensating coils. In this paper the magneto-static simulation results are presented illustrating different design considerations that led to a final design. Finally the shielding ability of the vacuum vessel is investigated experimentally through ambient magnetic field measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB090

Export •

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

TUPB099

Vertical Test System for Superconducting RF Cavities at Peking University

ion, cavity, radiation, controls

631

D. Zhou, J.E. Chen, W. Cheng, L.W. Feng, J.K. Hao, L. Lin, K.X. Liu, S.W. Quan, F. Wang, H.M. Xie, F. Zhu, D.H. Zhuang
PKU, Beijing, People's Republic of China

A new vertical test system (VTS) for superconducting RF cavities has been designed and constructed at Peking University. This facility is designed to operate at a temperature of 2K and with pumping speed of 10g/s for helium gas at 30 mbar. In this paper, we present the structure design, modification of 2K system, ambient magnetic field and radiation shielding, LLRF and the test run of this VTS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB099

Export •

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