SRF2019 - List of Authors (Kato, S.)

Paper	Title	Page
TUP021	Effect of Cathode Rotation and Acid Flow in Vertical Electropolishing of 1.3 GHz Niobium Nine-Cell Cavity	448
	V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi MGH, Hyogo-ken, Japan H. Hayano, S. Kato, H. Monjushiro, T. Saeki KEK, Ibaraki, Japan
	We have been carrying out R&D on vertical electropolishing (VEP) technique to establish it as an alternate of the horizontal EP (HEP) technique used for the surface treatment of niobium (Nb) superconducting RF (SRF) cavities. We have earlier reported on a VEP parameter study for 1.3 GHz single and nine-cell Nb cavities. The optimized VEP parameters and a unique rotating cathode yielded uniform removal and a smooth surface in the single cell cavity. The unique cathode and a dual flow mechanism for acid circulation were applied to improve the removal uniformity in the nine-cell cavity. The vertically electropolished single and nine cell cavities achieved the same RF performance as achieved after the HEP processes. We are making efforts to further improve the removal uniformity in the nine-cell cavity. Here, we report on a VEP of the 1.3 GHz Nb nine-cell cavity at a higher cathode rotation speed of 50 rpm. The VEP results reveal that the speed could be considered for improving the uniformity in removal while maintaining the surface smoothness. Required improvements in the VEP facility and acid flow condition for achieving uniform EP and a smooth surface are also described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP021
About •	paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP027	Vertical Electropolishing of Niobium Nine-Cell Cavity with a Cavity Flipping System for Uniform Removal	467
	K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi MGH, Hyogo-ken, Japan H. Hayano, S. Kato, H. Monjushiro, T. Saeki KEK, Ibaraki, Japan
	Marui Galvanizing Co., Ltd. has been developing vertical electropolishing (VEP) technology for single and nine-cell niobium superconducting radio frequency cavities using a unique cathode namely Ninja cathode in collaboration with KEK. The VEP process usually results in non-uniform removal with a large asymmetry along the cavity length. In order to suppress the asymmetry in removal, we are making different approaches. Flipping of the cavity during the VEP process is one of the approaches applied so far. A unique VEP setup, which allows the flipping of a multi-cell cavity, has been developed as reported earlier. Here, we report the improvement in the setup with automation for cavity flipping. VEP experiments were conducted with the improved system. VEP parameters were studied and the VEP results including the removal trend are discussed in detail.
	Poster TUP027 [1.347 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP027
About •	paper received ※ 24 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP028	Development of Vertical Electropolishing Facility for Nb 9-Cell Cavity (3)	470
	Y.I. Ida, V. Chouhan, K.N. Nii MGH, Hyogo-ken, Japan T. Akabori, G. Mitoya, K. Miyano HKK, Morioka, Japan Y. Anetai, F. Takahashi WING. Co.Ltd, Iwate-ken, Japan H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe KEK, Ibaraki, Japan
	The 1st report was delivered in May, 2018 at the IPAC 18 in Vancouver, Canada. The 2nd report was delivered in September, 2018 at the LINAC 18 in Beijing, China. We will make our 3rd report in July, 2019 at the SRF-19 in Dresden, Germany. There will be two main points this time. The first is that by using our improved Ninja Electrode Premium, we can out-perform our number one and number two competitors in terms of uniform electropolishing of the interior of the 9-cell cavity. The second point is that we can remove hydrogen gas, reacted during electropolishing, from the cavity chambers in a manner that has not been successfully achieved by 1st report, May 2018 and 2nd report, September 2018. We will report our 9-cell vertical polishing revolver-type unit that solves the above two problems.
	Poster TUP028 [0.444 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP028
About •	paper received ※ 24 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Effect of Cathode Rotation and Acid Flow in Vertical Electropolishing of 1.3 GHz Niobium Nine-Cell Cavity

448

V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
H. Hayano, S. Kato, H. Monjushiro, T. Saeki
KEK, Ibaraki, Japan

We have been carrying out R&D on vertical electropolishing (VEP) technique to establish it as an alternate of the horizontal EP (HEP) technique used for the surface treatment of niobium (Nb) superconducting RF (SRF) cavities. We have earlier reported on a VEP parameter study for 1.3 GHz single and nine-cell Nb cavities. The optimized VEP parameters and a unique rotating cathode yielded uniform removal and a smooth surface in the single cell cavity. The unique cathode and a dual flow mechanism for acid circulation were applied to improve the removal uniformity in the nine-cell cavity. The vertically electropolished single and nine cell cavities achieved the same RF performance as achieved after the HEP processes. We are making efforts to further improve the removal uniformity in the nine-cell cavity. Here, we report on a VEP of the 1.3 GHz Nb nine-cell cavity at a higher cathode rotation speed of 50 rpm. The VEP results reveal that the speed could be considered for improving the uniformity in removal while maintaining the surface smoothness. Required improvements in the VEP facility and acid flow condition for achieving uniform EP and a smooth surface are also described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP021

About •

paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019

Export •

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

TUP027

Vertical Electropolishing of Niobium Nine-Cell Cavity with a Cavity Flipping System for Uniform Removal

467

K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
H. Hayano, S. Kato, H. Monjushiro, T. Saeki
KEK, Ibaraki, Japan

Marui Galvanizing Co., Ltd. has been developing vertical electropolishing (VEP) technology for single and nine-cell niobium superconducting radio frequency cavities using a unique cathode namely Ninja cathode in collaboration with KEK. The VEP process usually results in non-uniform removal with a large asymmetry along the cavity length. In order to suppress the asymmetry in removal, we are making different approaches. Flipping of the cavity during the VEP process is one of the approaches applied so far. A unique VEP setup, which allows the flipping of a multi-cell cavity, has been developed as reported earlier. Here, we report the improvement in the setup with automation for cavity flipping. VEP experiments were conducted with the improved system. VEP parameters were studied and the VEP results including the removal trend are discussed in detail.

Poster TUP027 [1.347 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP027

About •

paper received ※ 24 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

TUP028

Development of Vertical Electropolishing Facility for Nb 9-Cell Cavity (3)

470

Y.I. Ida, V. Chouhan, K.N. Nii
MGH, Hyogo-ken, Japan
T. Akabori, G. Mitoya, K. Miyano
HKK, Morioka, Japan
Y. Anetai, F. Takahashi
WING. Co.Ltd, Iwate-ken, Japan
H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
KEK, Ibaraki, Japan

The 1st report was delivered in May, 2018 at the IPAC 18 in Vancouver, Canada. The 2nd report was delivered in September, 2018 at the LINAC 18 in Beijing, China. We will make our 3rd report in July, 2019 at the SRF-19 in Dresden, Germany. There will be two main points this time. The first is that by using our improved Ninja Electrode Premium, we can out-perform our number one and number two competitors in terms of uniform electropolishing of the interior of the 9-cell cavity. The second point is that we can remove hydrogen gas, reacted during electropolishing, from the cavity chambers in a manner that has not been successfully achieved by 1st report, May 2018 and 2nd report, September 2018. We will report our 9-cell vertical polishing revolver-type unit that solves the above two problems.

Poster TUP028 [0.444 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP028

About •

paper received ※ 24 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019

Export •

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