LINAC2018 - List of Authors (Yamamoto, Y.)

Paper	Title	Page
TUPO065	Improvement of Cavity Performance by Nitrogen Doping at KEK	480
SPWR019	use link to see paper's listing under its alternate paper code
	T. Okada, Y. Hori, E. Kako, T. Konomi, H. Sakai, K. Umemori, Y. Yamamoto Sokendai, Ibaraki, Japan T. Dohmae, Y. Hori, E. Kako, T. Konomi, T. Saeki, T. Saeki, H. Sakai, K. Umemori, Y. Yamamoto KEK, Ibaraki, Japan J. Kamiya JAEA/J-PARC, Tokai-mura, Japan S. Kurosawa, K. Takeishi JAEA, Ibaraki-ken, Japan
	Nitrogen doping experiments in single-cell and 3-cell niobium cavities were carried out at KEK. After annealing at 800 deg C for 3 hours, pure nitrogen gas with a pressure of 3 Pa for 20 minutes and 3 minutes were introduced for doping in a furnace in J-PARC, respectively. Removing surface in 5 um and 20 um by electropolishing were performed prior to the vertical tests, respectively. Increases of a quality factor at 2K and reduction of the BCS resistance with respect to an accelerating gradient were observed in both cavities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO065
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPO071	Study on Nitrogen Infusion for 1.3 GHz SRF Cavities Using J-PARC Furnace	499
	K. Umemori, T. Dohmae, M. Egi, Y. Hori, E. Kako, T. Konomi, S. Michizono, T. Saeki, H. Sakai, Y. Yamamoto KEK, Ibaraki, Japan J. Kamiya JAEA/J-PARC, Tokai-mura, Japan S. Kurosawa, K. Takeishi JAEA, Ibaraki-ken, Japan T. Okada Sokendai, Ibaraki, Japan
	Nitrogen infusion (N-infusion) is new surface treatment technique for niobium SRF (Superconducting RF) cavities. After cooling down from 800 degree C heat treatment, a vacuum furnace and cavities are kept 120 degree C, 48 hours with about 3 Pa Nitrogen. Improvement of Q-value and accelerating gradient is expected. We used J-PARC furnace, since N-infusion procedure requires clean vacuum furnace. It has a cryo-pump and turbo molecular pumps and its vacuum system is oil-free system. Six times of N-infusion tests were carried out, while changing vacuum condition, N-infusion temperature, Nitrogen pressure, niobium material and so on. Niobium caps were mounted on cavities to avoid contaminations on inner surfaces. Some of trials were successful and vertical test results showed improvement of Q-values and accelerating gradient. However, some of them were not. Most of bad cases showed degradation of Q-values above 5 MV/m. Details of heat treatment procedure including N-infusion and vertical test results are shown in this presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO071
About •	paper received ※ 20 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPO097	Recent Results for Study of Ceramic and Copper Plating for Power Couplers	905
	Y. Yamamoto, E. Kako, S. Michizono KEK, Ibaraki, Japan E. Cenni CEA/IRFU, Gif-sur-Yvette, France A. Four CEA/DRF/IRFU, Gif-sur-Yvette, France Y. Okii Nomura Plating Co, Ltd., Osaka, Japan
	KEK has conducted a survey to select an optimum ceramic after withdrawal by a domestic manufacturing company two years ago. For this selection, there are four important items on the properties of ceramic; that is, relative permittivity, dielectric loss tangent, surface and volume resistance, and secondary electron emission coefficient. For measurements of these parameters, five kinds of ceramic samples supplied from three companies were measured using three kinds of measurement systems. For measurement of secondary electron emission, scanning electron microscope (SEM) with beam blanking system was used. On the other hand, residual resistivity ratio (RRR) for copper plating, which is the most important item for quality control, has also been carried out while changing plating thickness and acid temperature. In this report, the recent results for these studies will be presented in detailed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO097
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

TUPO065

Improvement of Cavity Performance by Nitrogen Doping at KEK

480

SPWR019

use link to see paper's listing under its alternate paper code

T. Okada, Y. Hori, E. Kako, T. Konomi, H. Sakai, K. Umemori, Y. Yamamoto
Sokendai, Ibaraki, Japan
T. Dohmae, Y. Hori, E. Kako, T. Konomi, T. Saeki, T. Saeki, H. Sakai, K. Umemori, Y. Yamamoto
KEK, Ibaraki, Japan
J. Kamiya
JAEA/J-PARC, Tokai-mura, Japan
S. Kurosawa, K. Takeishi
JAEA, Ibaraki-ken, Japan

Nitrogen doping experiments in single-cell and 3-cell niobium cavities were carried out at KEK. After annealing at 800 deg C for 3 hours, pure nitrogen gas with a pressure of 3 Pa for 20 minutes and 3 minutes were introduced for doping in a furnace in J-PARC, respectively. Removing surface in 5 um and 20 um by electropolishing were performed prior to the vertical tests, respectively. Increases of a quality factor at 2K and reduction of the BCS resistance with respect to an accelerating gradient were observed in both cavities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO065

About •

paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

Export •

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

TUPO071

Study on Nitrogen Infusion for 1.3 GHz SRF Cavities Using J-PARC Furnace

499

K. Umemori, T. Dohmae, M. Egi, Y. Hori, E. Kako, T. Konomi, S. Michizono, T. Saeki, H. Sakai, Y. Yamamoto
KEK, Ibaraki, Japan
J. Kamiya
JAEA/J-PARC, Tokai-mura, Japan
S. Kurosawa, K. Takeishi
JAEA, Ibaraki-ken, Japan
T. Okada
Sokendai, Ibaraki, Japan

Nitrogen infusion (N-infusion) is new surface treatment technique for niobium SRF (Superconducting RF) cavities. After cooling down from 800 degree C heat treatment, a vacuum furnace and cavities are kept 120 degree C, 48 hours with about 3 Pa Nitrogen. Improvement of Q-value and accelerating gradient is expected. We used J-PARC furnace, since N-infusion procedure requires clean vacuum furnace. It has a cryo-pump and turbo molecular pumps and its vacuum system is oil-free system. Six times of N-infusion tests were carried out, while changing vacuum condition, N-infusion temperature, Nitrogen pressure, niobium material and so on. Niobium caps were mounted on cavities to avoid contaminations on inner surfaces. Some of trials were successful and vertical test results showed improvement of Q-values and accelerating gradient. However, some of them were not. Most of bad cases showed degradation of Q-values above 5 MV/m. Details of heat treatment procedure including N-infusion and vertical test results are shown in this presentation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO071

About •

paper received ※ 20 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

Export •

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

THPO097

Recent Results for Study of Ceramic and Copper Plating for Power Couplers

905

Y. Yamamoto, E. Kako, S. Michizono
KEK, Ibaraki, Japan
E. Cenni
CEA/IRFU, Gif-sur-Yvette, France
A. Four
CEA/DRF/IRFU, Gif-sur-Yvette, France
Y. Okii
Nomura Plating Co, Ltd., Osaka, Japan

KEK has conducted a survey to select an optimum ceramic after withdrawal by a domestic manufacturing company two years ago. For this selection, there are four important items on the properties of ceramic; that is, relative permittivity, dielectric loss tangent, surface and volume resistance, and secondary electron emission coefficient. For measurements of these parameters, five kinds of ceramic samples supplied from three companies were measured using three kinds of measurement systems. For measurement of secondary electron emission, scanning electron microscope (SEM) with beam blanking system was used. On the other hand, residual resistivity ratio (RRR) for copper plating, which is the most important item for quality control, has also been carried out while changing plating thickness and acid temperature. In this report, the recent results for these studies will be presented in detailed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO097

About •

paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

Export •

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