SRF2013 - List of Authors (Xie, Y.)

Paper

Title

Page

New Insights Into Quench Caused by Surface Pits in SRF Cavities

378

Y. Xie, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by NSF Career award PHY-0841213 and the Alfred P. Sloan Foundation.
Surface defects such as pits have been identified as some of the main sources of limitations of srf cavity performance. A single cell cavity with 30 artificial pits in the high magnetic field region was made to gain new insight in how pits limit the cavity performance*. The test of the pit cavity showed clear evidence that the edges of two of the largest radius pits transitioned into the normal conducting state at field just below the quench field of the cavity, and that the quench was indeed induced by these two pits. The pit geometrical information measured by laser confocal microscopy combined with a numerical finite element ring-type defect model will be compared with temperature mapping results. Insights about quench and non-linear rf resistances will be presented.
*Y. Xie, PhD thesis, Cornell University, 2013

Slides TUIOA05 [3.101 MB]

TUP090

Thermal Simulations for the Multi-Layer Coating Model

674

F. Meng
IHEP, Beijing, People's Republic of China
A. Romanenko
Fermilab, Batavia, USA
Y. Xie
Euclid TechLabs, LLC, Solon, Ohio, USA

Thermal simulations for the multi-layer coating model has been developed based on previous work of a finite difference thermal feedback code.* RF field-attenuation formula for the multi-layer coating model has also been included.** The temperature distribution along different superconducting layers under applied magnetic fields has been calculated with various superconducting material parameters.
*Y. Xie et.al., "Relationship between defects pre-heating and defects size", SRF2009.
**T. Kubo et.al.,"Rf field-attenuation formulae for the multilayer coating model", IPAC2013

THP002

Design of 3-Cell Travelling Wave Cavity for High Gradient Test

892

P.V. Avrakhov, A. Kanareykin, R.A. Kostin, Y. Xie
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Kazakov, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

Utilization of a superconducting traveling wave accelerating (STWA) structure with small phase advance per cell for future high energy linear colliders may provide accelerating gradient 1.2/1.4 times larger [1] than standing wave structure. However, the STWA structure requires a feedback waveguide [1]. Recent tests of 1.3 GHz model of a single-cell cavity with waveguide feedback demonstrated an accelerating gradient comparable to the gradient in a single-cell ILC-type cavity from the same manufacturer [2]. In the present paper a design for a STWA resonator with a 3-cell accelerating cavity for high gradient tests is considered. Methods to create and support the traveling wave in this structure are discussed. The results of detailed studies of the mechanical and tuning properties of the superconducting resonator with 3-cell traveling wave accelerating structure are also presented.

THP074

Update on Quarter-Wave Coaxial Coupler for 1.3GHz Superconducting Cavity

Y. Xie, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

Funding: This Work is supported by the U.S. DOE SBIR contract DE-SC002479.
A new quarter-wave coaxial detachable coupler that preserves the axial symmetry of the cavity geometry and rf field of the 1.3 GHz superconducting cavity has been designed by Euclid Techlabs. A flange with superconducting joint is placed at the zero magnetic field region on the beam tube for the connection between coupler and the cavity. This design also enables processing coupler separately. Update on the engineering design, fabrication process will be reported. The rf test of the coaxial detachable coupler with a single cell cavity is scheduled at the end of 2013.

Paper	Title	Page
TUIOA05	New Insights Into Quench Caused by Surface Pits in SRF Cavities	378
	Y. Xie, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by NSF Career award PHY-0841213 and the Alfred P. Sloan Foundation. Surface defects such as pits have been identified as some of the main sources of limitations of srf cavity performance. A single cell cavity with 30 artificial pits in the high magnetic field region was made to gain new insight in how pits limit the cavity performance. The test of the pit cavity showed clear evidence that the edges of two of the largest radius pits transitioned into the normal conducting state at field just below the quench field of the cavity, and that the quench was indeed induced by these two pits. The pit geometrical information measured by laser confocal microscopy combined with a numerical finite element ring-type defect model will be compared with temperature mapping results. Insights about quench and non-linear rf resistances will be presented. Y. Xie, PhD thesis, Cornell University, 2013
	Slides TUIOA05 [3.101 MB]

TUP090	Thermal Simulations for the Multi-Layer Coating Model	674
	F. Meng IHEP, Beijing, People's Republic of China A. Romanenko Fermilab, Batavia, USA Y. Xie Euclid TechLabs, LLC, Solon, Ohio, USA
	Thermal simulations for the multi-layer coating model has been developed based on previous work of a finite difference thermal feedback code.* RF field-attenuation formula for the multi-layer coating model has also been included.** The temperature distribution along different superconducting layers under applied magnetic fields has been calculated with various superconducting material parameters. Y. Xie et.al., "Relationship between defects pre-heating and defects size", SRF2009. *T. Kubo et.al.,"Rf field-attenuation formulae for the multilayer coating model", IPAC2013

THP002	Design of 3-Cell Travelling Wave Cavity for High Gradient Test	892
	P.V. Avrakhov, A. Kanareykin, R.A. Kostin, Y. Xie Euclid TechLabs, LLC, Solon, Ohio, USA S. Kazakov, N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA
	Utilization of a superconducting traveling wave accelerating (STWA) structure with small phase advance per cell for future high energy linear colliders may provide accelerating gradient 1.2/1.4 times larger [1] than standing wave structure. However, the STWA structure requires a feedback waveguide [1]. Recent tests of 1.3 GHz model of a single-cell cavity with waveguide feedback demonstrated an accelerating gradient comparable to the gradient in a single-cell ILC-type cavity from the same manufacturer [2]. In the present paper a design for a STWA resonator with a 3-cell accelerating cavity for high gradient tests is considered. Methods to create and support the traveling wave in this structure are discussed. The results of detailed studies of the mechanical and tuning properties of the superconducting resonator with 3-cell traveling wave accelerating structure are also presented.

THP074	Update on Quarter-Wave Coaxial Coupler for 1.3GHz Superconducting Cavity
	Y. Xie, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA
	Funding: This Work is supported by the U.S. DOE SBIR contract DE-SC002479. A new quarter-wave coaxial detachable coupler that preserves the axial symmetry of the cavity geometry and rf field of the 1.3 GHz superconducting cavity has been designed by Euclid Techlabs. A flange with superconducting joint is placed at the zero magnetic field region on the beam tube for the connection between coupler and the cavity. This design also enables processing coupler separately. Update on the engineering design, fabrication process will be reported. The rf test of the coaxial detachable coupler with a single cell cavity is scheduled at the end of 2013.