LINAC2016 - Classification: 1 Electron Accelerators and Applications / 1E Colliders

Paper	Title	Page
MO3A02	Achievement of Small Beam Size at ATF2 Beamline	27
	T. Okugi KEK, Ibaraki, Japan
	The beam commissioning of the ATF2 facility at KEK - a 1.3 GeV prototype of the compact local chromaticity correction final focus system for the linear collider - achieved 44nm beam size, very close to ideal expected size of 37nm, by developing various knobs and improving the performances of the interferometric Shintake monitor at the same time. These results have opened the way to reliable and predictable operation of the linear collider.
	Slides MO3A02 [3.495 MB]
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MOP106002	X-Band Photonic Band Gap Accelerating Structures with Improved Wakefield Suppression	307
	E.I. Simakov LANL, Los Alamos, New Mexico, USA
	Funding: This work is supported by U.S. Department of Energy (DOE) Office of High Energy Physics. We present the design of a novel photonic band gap (PBG) accelerating structure with elliptical rods and improved wakefields suppression. It has been long recognized that PBG structures have great potential in reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in room-temperature PBG structures was conducted at MIT in 2005. The experimental characterization of the wakefield spectrum in a beam test was performed at Argonne Wakefield Accelerator facility in 2015, and the superior wakefield suppression properties of the PBG structure were demonstrated. In 2013 the team from MIT and SLAC demonstrated that the X-band PBG structures with elliptical rods have reduced breakdown rate compared to PBG structures with round rods, presumably due to the reduced surface magnetic fields. However, the structure with elliptical rods designed by MIT confined the dipole higher order mode in addition to the accelerating mode and thus did not have superior wakefield suppression properties. We demonstrate that PBG resonators can be designed with 40% smaller peak surface magnetic fields while preserving and even improving their wakefield suppression properties as compared to the structure with round rods. The design of the new structure is presented. The structure will be fabricated, tuned, and tested for high gradients and for wakefield suppression.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOP106002
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MOP106021	Superconducting Traveling Wave Cavity Tuning Studies	327
	R.A. Kostin LETI, Saint-Petersburg, Russia P.V. Avrakhov, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by US DOE SBIR # DE-SC0006300 Superconducting traveling wave cavity (SCTW) can provide 1.2-1.4 times larger accelerating gradient than conventional standing wave SRF cavities [1]. Firstly, traveling wave opens the way to use other than Pi-mode phase advance per cell which increase transit time factor. Secondly, traveling wave is not so sensitive to cavity length as standing wave, which length is limited to 1 meter because of field flatness degradation. 3 cell SCTW cavity was proposed [2] and built for high gradient traveling wave demonstration and tuning studies. This paper describes analytical model that was used for cavity development. Tuning properties and requirements are also discussed. ' r.kostin@euclidtechlabs.com
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOP106021
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TUPLR007	LCLS-II Cryomodules Production at Fermilab	481
	T.T. Arkan, C.J. Grimm, J.A. Kaluzny, Y.O. Orlov, T.J. Peterson, K. Premo Fermilab, Batavia, Illinois, USA
	Funding: US DOE LCLS-II is an upgrade project for the linear coherent light source (LCLS) at SLAC. The LCLS-II linac will consist of thirty-five 1.3 GHz and two 3.9 GHz superconducting RF continuous wave (CW) cryomodules that Fermilab and Jefferson Lab (JLab) will assemble in collaboration with SLAC. The LCLS-II 1.3 GHz cryomodule design is based on the European XFEL pulsed-mode cryomodule design with modifications needed for CW operation. Fermilab and JLab will each assemble and test a prototype 1.3 GHz cryomodule to assess the results of the CW modifications, in advance of 16 and 17 production 1.3 GHz cryomodules, respectively. Fermilab is solely responsible for the 3.9 GHz cryomodules. After the prototype cryomodule tests are complete and lessons learned incorporated, both laboratories will increase their cryomodule production rates to meet the challenging LCLS-II project requirement of approximately one cryomodule per month per laboratory. This paper presents the Fermilab Cryomodule Assembly Facility (CAF) infrastructure for LCLS-II cryomodule production, the Fermilab prototype 1.3 GHz CW cryomodule (pCM) assembly and readiness for production assembly.
	Poster TUPLR007 [2.474 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR007
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THPLR003	Fabrication and High-Gradient Testing of an Accelerating Structure Made From Milled Halves	845
	W. Wuensch, T. Argyropoulos, N. Catalán Lasheras, D. Esperante Pereira, J. Giner Navarro, A. Grudiev, G. McMonagle, I. Syratchev, B.J. Woolley, H. Zha CERN, Geneva, Switzerland T. Argyropoulos, D. Esperante Pereira, J. Giner Navarro IFIC, Valencia, Spain G.B. Bowden, V.A. Dolgashev, A.A. Haase SLAC, Menlo Park, California, USA P.J. Giansiracusa, T.G. Lucas, M. Volpi The University of Melbourne, Melbourne, Victoria, Australia R. Rajamaki Aalto University, School of Science and Technology, Aalto, Finland X.F.D. Stragier TUE, Eindhoven, The Netherlands
	Accelerating structures made from parts which follow symmetry planes offer many potential advantages over traditional disk-based structures: more options for joining (from bonding to welding), following this more options for material state (heat treated or not) and potentially lower cost since structures can be made from fewer parts. An X-band structure made from milled halves, and with a standard benchmarked CLIC test structure design has been fabricated and high-gradient tested in the range of 100 MV/m.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR003
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THPLR004	Development of 1.3 Ghz Single-Cell Superconducting Cavities With Nb Material Developed by Ulba Metallurgical Plant	849
	T. Ota, N. Kuroiwa, S. Nomura, Y. Otani, M. Takasaki, M. Yamada Toshiba, Yokohama, Japan H. Hayano, T. Saeki KEK, Ibaraki, Japan Y.V. Krygin, V. Kuznetsov, A.A. Tsorayev Ulba Metallurgical Plant, Ust-Kamenogorak, Kazakhstan Y. Shirota BE International Corporation, Tokyo, Japan T. Tosaka Toshiba Corporation, Power And Industrial Systems Research and Development Center, Yokohama, Japan
	TOSHIBA has been developing high purity niobium (Nb) material for superconducting cavities with ULBA Metallurgical Plant (UMP) since 2008. Recently, we have produced the high purity Nb plates. Two 1.3 GHz single-cell superconducting cavities using UMP's Nb plates have been fabricated by TOSHIBA and RF tested at High Energy Accelerator Research Organization (KEK). One of the cavities has achieved the accelerating gradient of Eacc=31.8 MV/m. The development of high purity Nb plates, details of the fabrication of the cavities and the RF test results are presented in this article.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR004
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THPLR006	Design Study of a Test Cavity for Evaluating RF Critical Magnetic Field of Thin-Film Superconductor	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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THPLR008	3-Cell Superconducting Traveling Wave Cavity Tuning at Room Temperature	858
	R.A. Kostin LETI, Saint-Petersburg, Russia P.V. Avrakhov, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA T.N. Khabiboulline, A.M. Rowe, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by US DOE SBIR # DE-SC0006300 A superconducting traveling wave (SCTW) cavity with a feedback waveguide will support a higher average acceleration gradient compared to conventional SRF standing wave cavities [1]. Euclid Techlabs, in collaboration with Fermilab, previously demonstrated a high accelerating gradient in a single cell cavity with a feedback waveguide [2], and the new waveguide design did not limit the cavity performance. The next step is high gradient traveling wave SRF cavity test. A 3-Cell SCTW cavity was designed and developed [3] to demonstrate the SRF traveling wave regime. Two Nb SCTW cavities were built, characterized and cold tested in 2016. This paper presents the results of cavity inspection, field flatness analysis, along with a discussion of the tuning procedure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR008
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Achievement of Small Beam Size at ATF2 Beamline

27

T. Okugi
KEK, Ibaraki, Japan

The beam commissioning of the ATF2 facility at KEK - a 1.3 GeV prototype of the compact local chromaticity correction final focus system for the linear collider - achieved 44nm beam size, very close to ideal expected size of 37nm, by developing various knobs and improving the performances of the interferometric Shintake monitor at the same time. These results have opened the way to reliable and predictable operation of the linear collider.

Slides MO3A02 [3.495 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MO3A02

Export •

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

MOP106002

X-Band Photonic Band Gap Accelerating Structures with Improved Wakefield Suppression

307

E.I. Simakov
LANL, Los Alamos, New Mexico, USA

Funding: This work is supported by U.S. Department of Energy (DOE) Office of High Energy Physics.
We present the design of a novel photonic band gap (PBG) accelerating structure with elliptical rods and improved wakefields suppression. It has been long recognized that PBG structures have great potential in reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in room-temperature PBG structures was conducted at MIT in 2005. The experimental characterization of the wakefield spectrum in a beam test was performed at Argonne Wakefield Accelerator facility in 2015, and the superior wakefield suppression properties of the PBG structure were demonstrated. In 2013 the team from MIT and SLAC demonstrated that the X-band PBG structures with elliptical rods have reduced breakdown rate compared to PBG structures with round rods, presumably due to the reduced surface magnetic fields. However, the structure with elliptical rods designed by MIT confined the dipole higher order mode in addition to the accelerating mode and thus did not have superior wakefield suppression properties. We demonstrate that PBG resonators can be designed with 40% smaller peak surface magnetic fields while preserving and even improving their wakefield suppression properties as compared to the structure with round rods. The design of the new structure is presented. The structure will be fabricated, tuned, and tested for high gradients and for wakefield suppression.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOP106002

Export •

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MOP106021

Superconducting Traveling Wave Cavity Tuning Studies

327

R.A. Kostin
LETI, Saint-Petersburg, Russia
P.V. Avrakhov, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by US DOE SBIR # DE-SC0006300
Superconducting traveling wave cavity (SCTW) can provide 1.2-1.4 times larger accelerating gradient than conventional standing wave SRF cavities [1]. Firstly, traveling wave opens the way to use other than Pi-mode phase advance per cell which increase transit time factor. Secondly, traveling wave is not so sensitive to cavity length as standing wave, which length is limited to 1 meter because of field flatness degradation. 3 cell SCTW cavity was proposed [2] and built for high gradient traveling wave demonstration and tuning studies. This paper describes analytical model that was used for cavity development. Tuning properties and requirements are also discussed.
' r.kostin@euclidtechlabs.com

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOP106021

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TUPLR007

LCLS-II Cryomodules Production at Fermilab

481

T.T. Arkan, C.J. Grimm, J.A. Kaluzny, Y.O. Orlov, T.J. Peterson, K. Premo
Fermilab, Batavia, Illinois, USA

Funding: US DOE
LCLS-II is an upgrade project for the linear coherent light source (LCLS) at SLAC. The LCLS-II linac will consist of thirty-five 1.3 GHz and two 3.9 GHz superconducting RF continuous wave (CW) cryomodules that Fermilab and Jefferson Lab (JLab) will assemble in collaboration with SLAC. The LCLS-II 1.3 GHz cryomodule design is based on the European XFEL pulsed-mode cryomodule design with modifications needed for CW operation. Fermilab and JLab will each assemble and test a prototype 1.3 GHz cryomodule to assess the results of the CW modifications, in advance of 16 and 17 production 1.3 GHz cryomodules, respectively. Fermilab is solely responsible for the 3.9 GHz cryomodules. After the prototype cryomodule tests are complete and lessons learned incorporated, both laboratories will increase their cryomodule production rates to meet the challenging LCLS-II project requirement of approximately one cryomodule per month per laboratory. This paper presents the Fermilab Cryomodule Assembly Facility (CAF) infrastructure for LCLS-II cryomodule production, the Fermilab prototype 1.3 GHz CW cryomodule (pCM) assembly and readiness for production assembly.

Poster TUPLR007 [2.474 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR007

Export •

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

THPLR003

Fabrication and High-Gradient Testing of an Accelerating Structure Made From Milled Halves

845

W. Wuensch, T. Argyropoulos, N. Catalán Lasheras, D. Esperante Pereira, J. Giner Navarro, A. Grudiev, G. McMonagle, I. Syratchev, B.J. Woolley, H. Zha
CERN, Geneva, Switzerland
T. Argyropoulos, D. Esperante Pereira, J. Giner Navarro
IFIC, Valencia, Spain
G.B. Bowden, V.A. Dolgashev, A.A. Haase
SLAC, Menlo Park, California, USA
P.J. Giansiracusa, T.G. Lucas, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
R. Rajamaki
Aalto University, School of Science and Technology, Aalto, Finland
X.F.D. Stragier
TUE, Eindhoven, The Netherlands

Accelerating structures made from parts which follow symmetry planes offer many potential advantages over traditional disk-based structures: more options for joining (from bonding to welding), following this more options for material state (heat treated or not) and potentially lower cost since structures can be made from fewer parts. An X-band structure made from milled halves, and with a standard benchmarked CLIC test structure design has been fabricated and high-gradient tested in the range of 100 MV/m.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR003

Export •

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

THPLR004

Development of 1.3 Ghz Single-Cell Superconducting Cavities With Nb Material Developed by Ulba Metallurgical Plant

849

T. Ota, N. Kuroiwa, S. Nomura, Y. Otani, M. Takasaki, M. Yamada
Toshiba, Yokohama, Japan
H. Hayano, T. Saeki
KEK, Ibaraki, Japan
Y.V. Krygin, V. Kuznetsov, A.A. Tsorayev
Ulba Metallurgical Plant, Ust-Kamenogorak, Kazakhstan
Y. Shirota
BE International Corporation, Tokyo, Japan
T. Tosaka
Toshiba Corporation, Power And Industrial Systems Research and Development Center, Yokohama, Japan

TOSHIBA has been developing high purity niobium (Nb) material for superconducting cavities with ULBA Metallurgical Plant (UMP) since 2008. Recently, we have produced the high purity Nb plates. Two 1.3 GHz single-cell superconducting cavities using UMP's Nb plates have been fabricated by TOSHIBA and RF tested at High Energy Accelerator Research Organization (KEK). One of the cavities has achieved the accelerating gradient of Eacc=31.8 MV/m. The development of high purity Nb plates, details of the fabrication of the cavities and the RF test results are presented in this article.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR004

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

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)

THPLR008

3-Cell Superconducting Traveling Wave Cavity Tuning at Room Temperature

858

R.A. Kostin
LETI, Saint-Petersburg, Russia
P.V. Avrakhov, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
T.N. Khabiboulline, A.M. Rowe, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by US DOE SBIR # DE-SC0006300
A superconducting traveling wave (SCTW) cavity with a feedback waveguide will support a higher average acceleration gradient compared to conventional SRF standing wave cavities [1]. Euclid Techlabs, in collaboration with Fermilab, previously demonstrated a high accelerating gradient in a single cell cavity with a feedback waveguide [2], and the new waveguide design did not limit the cavity performance. The next step is high gradient traveling wave SRF cavity test. A 3-Cell SCTW cavity was designed and developed [3] to demonstrate the SRF traveling wave regime. Two Nb SCTW cavities were built, characterized and cold tested in 2016. This paper presents the results of cavity inspection, field flatness analysis, along with a discussion of the tuning procedure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR008

Export •

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