SRF2013 - List of Authors (Solyak, N.)

Paper

Title

Page

Status of the SRF Development for the Project X

117

V.P. Yakovlev, T.T. Arkan, M.H. Awida, P. Berrutti, E. Borissov, A.C. Crawford, M.H. Foley, C.M. Ginsburg, I.V. Gonin, A. Grassellino, C.J. Grimm, S.D. Holmes, S. Kazakov, R.D. Kephart, T.N. Khabiboulline, V.A. Lebedev, A. Lunin, M. Merio, S. Nagaitsev, T.H. Nicol, Y.O. Orlov, D. Passarelli, T.J. Peterson, Y.M. Pischalnikov, O.V. Pronitchev, L. Ristori, A.M. Rowe, D.A. Sergatskov, N. Solyak, A.I. Sukhanov, I. Terechkine
Fermilab, Batavia, USA

Project X is a high intensity proton facility being developed to support a world-leading program of Intensity Frontier physics over the next two decades at Fermilab. The proposed facility is based on the SRF technology and consists of two linacs: CW linac to accelerate beam from 2.1 MeV to 3 GeV and pulsed linac accelerate 5% of the beam up to 8 GeV. In a CW linac five families of SC cavities are used: half-wave resonators (162.5 MHz); single-spoke cavities: SSR1 and SSR2 (325 MHz) and elliptical 5-cell β=0.6 and β=0.9 cavities (650 MHz). Pulsed 3-8 GeV linac linac are based on 9-cell 1.3 GHz cavities. In the paper the basic requirements and the status of development of SC accelerating cavities, auxiliaries (couplers, tuners, etc.) and cryomodules are presented as well as technology challenges caused by their specifics.

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.

THP029

Simulation of Mechanical Resonances of SRF Cavities in Low Beam Current CW Operation

962

N. Solyak, M.H. Awida, I.V. Gonin, T.N. Khabiboulline, Y.M. Pischalnikov, W. Schappert, V.P. Yakovlev
Fermilab, Batavia, USA

The low beam current for CW operation of the Project X requires cavities to be mechanically optimized to operate at a high loaded Q and thus, low bandwidth with higher sensitivity to microphonics. The essential source of microphonics detuning is fluctuations in the helium pressure df/dp. Last year’s several methods for reducing df/dp has been proposed. One of the other possible sources of RF frequency instability is mechanical resonances. The cavity could be driven out of operating frequency by the mechanical deformations due to vibrations caused by external factors. In this paper we present the COMSOL multiphysics algorithm developed for evaluation of operating frequency shift due to mechanical resonances in SC cavities. We discuss the results of simulations for 5-cell elliptical 650 MHz β=0.9 cavities. The comparison of COMSOL simulations and measurements of ILC type cavities in Horizontal Test Stand at Fermilab is 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.

THP080

SRF Cavity Tuning for Low Beam Loading

1110

N. Solyak, E. Borissov, I.V. Gonin, C.J. Grimm, T.N. Khabiboulline, R.V. Pilipenko, Y.M. Pischalnikov, W. Schappert, V.P. Yakovlev
Fermilab, Batavia, USA

The design of 5-cell elliptical 650 MHz β=0.9 cavities to accelerate H⁻ beam of 1 mA average current in the range 467-3000 MeV for the Project X Linac is currently under development at Fermilab. The low beam current enables cavities to operate with high loaded Q’s and low bandwidth, making them very sensitive to microphonics. Mechanical vibrations and the Lorentz force can drive cavities off resonance during operation; therefore the proper design of the tuning system is very important part of cavity mechanical design. In this paper we review the design, performance, operation, reliability and cost of fast and slow tuners for 1.3 GHz elliptical cavities. We also present a design of the slow and fast tuners for 650 MHz β=0.9 cavities based on this experience. The HV in the new design is equipped with the tuners located at the end of the cavity instead of the initially proposed blade tuner located in the middle. We will present the results of ANSYS analyses of mechanical properties of tuners.

Paper	Title	Page
MOP015	Status of the SRF Development for the Project X	117
	V.P. Yakovlev, T.T. Arkan, M.H. Awida, P. Berrutti, E. Borissov, A.C. Crawford, M.H. Foley, C.M. Ginsburg, I.V. Gonin, A. Grassellino, C.J. Grimm, S.D. Holmes, S. Kazakov, R.D. Kephart, T.N. Khabiboulline, V.A. Lebedev, A. Lunin, M. Merio, S. Nagaitsev, T.H. Nicol, Y.O. Orlov, D. Passarelli, T.J. Peterson, Y.M. Pischalnikov, O.V. Pronitchev, L. Ristori, A.M. Rowe, D.A. Sergatskov, N. Solyak, A.I. Sukhanov, I. Terechkine Fermilab, Batavia, USA
	Project X is a high intensity proton facility being developed to support a world-leading program of Intensity Frontier physics over the next two decades at Fermilab. The proposed facility is based on the SRF technology and consists of two linacs: CW linac to accelerate beam from 2.1 MeV to 3 GeV and pulsed linac accelerate 5% of the beam up to 8 GeV. In a CW linac five families of SC cavities are used: half-wave resonators (162.5 MHz); single-spoke cavities: SSR1 and SSR2 (325 MHz) and elliptical 5-cell β=0.6 and β=0.9 cavities (650 MHz). Pulsed 3-8 GeV linac linac are based on 9-cell 1.3 GHz cavities. In the paper the basic requirements and the status of development of SC accelerating cavities, auxiliaries (couplers, tuners, etc.) and cryomodules are presented as well as technology challenges caused by their specifics.

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.

THP029	Simulation of Mechanical Resonances of SRF Cavities in Low Beam Current CW Operation	962
	N. Solyak, M.H. Awida, I.V. Gonin, T.N. Khabiboulline, Y.M. Pischalnikov, W. Schappert, V.P. Yakovlev Fermilab, Batavia, USA
	The low beam current for CW operation of the Project X requires cavities to be mechanically optimized to operate at a high loaded Q and thus, low bandwidth with higher sensitivity to microphonics. The essential source of microphonics detuning is fluctuations in the helium pressure df/dp. Last year’s several methods for reducing df/dp has been proposed. One of the other possible sources of RF frequency instability is mechanical resonances. The cavity could be driven out of operating frequency by the mechanical deformations due to vibrations caused by external factors. In this paper we present the COMSOL multiphysics algorithm developed for evaluation of operating frequency shift due to mechanical resonances in SC cavities. We discuss the results of simulations for 5-cell elliptical 650 MHz β=0.9 cavities. The comparison of COMSOL simulations and measurements of ILC type cavities in Horizontal Test Stand at Fermilab is 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.

THP080	SRF Cavity Tuning for Low Beam Loading	1110
	N. Solyak, E. Borissov, I.V. Gonin, C.J. Grimm, T.N. Khabiboulline, R.V. Pilipenko, Y.M. Pischalnikov, W. Schappert, V.P. Yakovlev Fermilab, Batavia, USA
	The design of 5-cell elliptical 650 MHz β=0.9 cavities to accelerate H⁻ beam of 1 mA average current in the range 467-3000 MeV for the Project X Linac is currently under development at Fermilab. The low beam current enables cavities to operate with high loaded Q’s and low bandwidth, making them very sensitive to microphonics. Mechanical vibrations and the Lorentz force can drive cavities off resonance during operation; therefore the proper design of the tuning system is very important part of cavity mechanical design. In this paper we review the design, performance, operation, reliability and cost of fast and slow tuners for 1.3 GHz elliptical cavities. We also present a design of the slow and fast tuners for 650 MHz β=0.9 cavities based on this experience. The HV in the new design is equipped with the tuners located at the end of the cavity instead of the initially proposed blade tuner located in the middle. We will present the results of ANSYS analyses of mechanical properties of tuners.