LINAC2016 - List of Keywords (electromagnetic-fields)

Paper	Title	Other Keywords	Page
MOPLR036	Study on Multilayer Thin Film Coating on Superconducting Cavity	cryogenics, operation, radio-frequency, controls	215
	Y. Iwashita, Y. Fuwa, H. Tongu Kyoto ICR, Uji, Kyoto, Japan H. Hayano, T. Kubo, T. Saeki KEK, Ibaraki, Japan M. Hino Kyoto University, Research Reactor Institute, Osaka, Japan H. Oikawa Utsunomiya University, Utsunomiya, Japan
	Funding: This research is supported by following programs: Grant-in-Aid for Exploratory Research 26600142 and Photon and Quantum Basic Research Coordinated Development Program from the MEXT. Multilayer thin film coating is a promising technology to enhance performance of superconducting cavities. Until recently, principal parameters to achieve the sufficient performance had not been known, such as the thickness of each layer. We proposed a method to deduce a set of the parameters to exhibit a good performances. In order to verify the scheme, we are trying to make some experiments on the subject at Kyoto. The sample preparation and the test setup for the measurement apparatus will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR036
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THPLR006	Design Study of a Test Cavity for Evaluating RF Critical Magnetic Field of Thin-Film Superconductor	cavity, target, cryogenics, resonance	852
	H. Oikawa Utsunomiya University, Utsunomiya, Japan H. Hayano, S. Kato, T. Kubo, T. Saeki KEK, Ibaraki, Japan T. Higashiguchi Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan M. Hino Kyoto University, Research Reactor Institute, Osaka, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan
	Superconducting cavities of higher gradient has been demanded in various fields of the accelerator science. Also, according to the Technical Design Report (TDR) of International Linear Collider (ILC), the higher gradient of 45 MV/m is required in the second stage of ILC. To realize such higher gradient, several methods are proposed. One of such methods is to coat multi-layer thin-film superconductor on the inner surface of RF cavity where the thin film increases the RF critical field on the inner surface of the cavity. To demonstrate the RF performance of thin-film structure on a small coupon sample, we designed the RF mushroom-shaped cavity with which the RF critical magnetic field is measured on a thin-film coupon sample set on the inner surface of the cavity. If the RF cavity is cooled down below the critical temperature of thin-film superconductor with supplying RF power, the heat dissipation might be measured on the coupon sample in the cavity. We designed the shape of the cavity so as to produce a strong RF magnetic field parallel to the sample surface efficiently. We report the design, manufacturing and RF property measurements of the cavity in this presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR006
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THPLR035	FZJ SRF TSR with Integrated LHe Vessel	cavity, simulation, SRF, operation	926
	E.N. Zaplatin FZJ, Jülich, Germany
	Single- or Multi-Spoke SRF cavities are one of the basic accelerating structures for the low and intermediate energy part of many accelerators. Different types of external loads on the resonator walls predetermine the main working conditions of the SC cavities. The most important of them are very high electromagnetic fields that result in strong Lorentz forces acting on cavity walls and the pressure on cavity walls from the helium tank that also deforms the cavity shape. For the accelerators operating in pulsed regime the Lorentz forces are the dominant factor. The liquid helium vessel pressure instability even for 2K operations is the source of large microphonics and dominates for cw operation. Here we propose an innovative integrated helium vessel-cavity and stiffener design that will provide an effective passive damping minimizing df/dp ratio. Minimizing df/dp may be accomplished without an enhancement of the structure rigidity, which in turn minimizes the load on the cavity tuner. A separate stiffening scheme reducing Lorentz force cavity detuning to be added without violation of df/dp optimization. The developed at the Research Center in Jülich, Germany (FZJ) the 352 MHz, β=v/c=0.48 Triple-Spoke Resonator was used as an example to demonstrate the proposed conceptual integrated helium vessel-cavity design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR035
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Paper

Title

Other Keywords

Page

MOPLR036

Study on Multilayer Thin Film Coating on Superconducting Cavity

cryogenics, operation, radio-frequency, controls

215

Y. Iwashita, Y. Fuwa, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
H. Hayano, T. Kubo, T. Saeki
KEK, Ibaraki, Japan
M. Hino
Kyoto University, Research Reactor Institute, Osaka, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

Funding: This research is supported by following programs: Grant-in-Aid for Exploratory Research 26600142 and Photon and Quantum Basic Research Coordinated Development Program from the MEXT.
Multilayer thin film coating is a promising technology to enhance performance of superconducting cavities. Until recently, principal parameters to achieve the sufficient performance had not been known, such as the thickness of each layer. We proposed a method to deduce a set of the parameters to exhibit a good performances. In order to verify the scheme, we are trying to make some experiments on the subject at Kyoto. The sample preparation and the test setup for the measurement apparatus will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR036

Export •

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

THPLR006

Design Study of a Test Cavity for Evaluating RF Critical Magnetic Field of Thin-Film Superconductor

cavity, target, cryogenics, resonance

852

H. Oikawa
Utsunomiya University, Utsunomiya, Japan
H. Hayano, S. Kato, T. Kubo, T. Saeki
KEK, Ibaraki, Japan
T. Higashiguchi
Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan
M. Hino
Kyoto University, Research Reactor Institute, Osaka, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan

Superconducting cavities of higher gradient has been demanded in various fields of the accelerator science. Also, according to the Technical Design Report (TDR) of International Linear Collider (ILC), the higher gradient of 45 MV/m is required in the second stage of ILC. To realize such higher gradient, several methods are proposed. One of such methods is to coat multi-layer thin-film superconductor on the inner surface of RF cavity where the thin film increases the RF critical field on the inner surface of the cavity. To demonstrate the RF performance of thin-film structure on a small coupon sample, we designed the RF mushroom-shaped cavity with which the RF critical magnetic field is measured on a thin-film coupon sample set on the inner surface of the cavity. If the RF cavity is cooled down below the critical temperature of thin-film superconductor with supplying RF power, the heat dissipation might be measured on the coupon sample in the cavity. We designed the shape of the cavity so as to produce a strong RF magnetic field parallel to the sample surface efficiently. We report the design, manufacturing and RF property measurements of the cavity in this presentation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR006

Export •

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

THPLR035

FZJ SRF TSR with Integrated LHe Vessel

cavity, simulation, SRF, operation

926

E.N. Zaplatin
FZJ, Jülich, Germany

Single- or Multi-Spoke SRF cavities are one of the basic accelerating structures for the low and intermediate energy part of many accelerators. Different types of external loads on the resonator walls predetermine the main working conditions of the SC cavities. The most important of them are very high electromagnetic fields that result in strong Lorentz forces acting on cavity walls and the pressure on cavity walls from the helium tank that also deforms the cavity shape. For the accelerators operating in pulsed regime the Lorentz forces are the dominant factor. The liquid helium vessel pressure instability even for 2K operations is the source of large microphonics and dominates for cw operation. Here we propose an innovative integrated helium vessel-cavity and stiffener design that will provide an effective passive damping minimizing df/dp ratio. Minimizing df/dp may be accomplished without an enhancement of the structure rigidity, which in turn minimizes the load on the cavity tuner. A separate stiffening scheme reducing Lorentz force cavity detuning to be added without violation of df/dp optimization. The developed at the Research Center in Jülich, Germany (FZJ) the 352 MHz, β=v/c=0.48 Triple-Spoke Resonator was used as an example to demonstrate the proposed conceptual integrated helium vessel-cavity design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR035

Export •

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