SRF2017 - List of Authors (Nagata, T.)

Paper	Title	Page
THPB034	Development of High Purity Niobium Components and Cavities for SRF Accelerator	814
	T. Nagata, H. Masui, S. Shinozawa ULVAC, Inc, Chiba, Japan H. Inoue, E. Kako, M. Yamanaka KEK, Ibaraki, Japan M. Murakami ULVAC, Inc., Tsukuba, Japan
	Comprehensive cavity fabrication process from Niobium ingot was investigated. In order to purify ingots, A 600 kW electron beam furnace was introduced in ULVAC. It makes possible the stable quality of Niobium sheets and tubes. In evaluation of chemical components, mechanical properties, and RRR of our materials, all the value satisfies the ASTM Type 5 (superconducting grade) specification. In this study, we performed the trial manufacturing of welding-type and seamless-type cavities were made of our high purity Niobium ingots (RRR > 300). Accelerating gradient over 40 MV/m was shown in both cavities. We also tried to manufacture a 3-cell seamless cavity as scale up study. A seamless tube with a length of 830 mm, an inner diameter of 131 mm and a thickness of 3.5 mm was prepared. We succeed in direct forming from tube to cavity shape by using a hydroforming process. Cavity surface could be smoother than that of single cell cavity caused by small crystal grain size.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB034
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THPB021	Trial of Nitrogen Infusion and Nitrogen Doping by Using J-PARC Furnace	775
	T. Konomi, T. Dohmae, Y. Hori, E. Kako, T. Kubo, G.-T. Park, H. Sakai, K. Umemori KEK, Ibaraki, Japan J. Kamiya, K. Takeishi JAEA/J-PARC, Tokai-mura, Japan T. Nagata ULVAC, Inc., Tsukuba, Japan
	KEK has been carrying out SRF cavity developments toward higher Q-values and higher accelerating gradients. In the past nitrogen-doping was tested using the KEK furnaces, but it did not succeed. This time nitrogen infusion and nitrogen doping are tested using the J-PARC's furnace, which has an oil-free pumping system and is mainly pumped by a 10000 L/s cryopump and three 3000 L/s turbo pumps. Nitrogen pressure is controlled by a variable leak valve and an additional turbo pump. To avoid performance degradation during heat treatment, flanges of cavities are covered by Nb caps and foils. Nitrogen infusion at 120 degrees was applied to a single cell cavity and cavity performance was measured by vertical tests after HPR and assembly. Nitrogen doping at 800 degrees is also applied to another single cell cavity. After applying EP and HPR, vertical tests were carried out. Nb samples were also installed into the furnace during heat treatment. Surfaces are analyzed by SIMS and XPS. In this presentation, we report procedure of nitrogen infusion and doping, vertical test results and results of surface analysis.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Development of High Purity Niobium Components and Cavities for SRF Accelerator

814

T. Nagata, H. Masui, S. Shinozawa
ULVAC, Inc, Chiba, Japan
H. Inoue, E. Kako, M. Yamanaka
KEK, Ibaraki, Japan
M. Murakami
ULVAC, Inc., Tsukuba, Japan

Comprehensive cavity fabrication process from Niobium ingot was investigated. In order to purify ingots, A 600 kW electron beam furnace was introduced in ULVAC. It makes possible the stable quality of Niobium sheets and tubes. In evaluation of chemical components, mechanical properties, and RRR of our materials, all the value satisfies the ASTM Type 5 (superconducting grade) specification. In this study, we performed the trial manufacturing of welding-type and seamless-type cavities were made of our high purity Niobium ingots (RRR > 300). Accelerating gradient over 40 MV/m was shown in both cavities. We also tried to manufacture a 3-cell seamless cavity as scale up study. A seamless tube with a length of 830 mm, an inner diameter of 131 mm and a thickness of 3.5 mm was prepared. We succeed in direct forming from tube to cavity shape by using a hydroforming process. Cavity surface could be smoother than that of single cell cavity caused by small crystal grain size.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB034

Export •

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

THPB021

Trial of Nitrogen Infusion and Nitrogen Doping by Using J-PARC Furnace

775

T. Konomi, T. Dohmae, Y. Hori, E. Kako, T. Kubo, G.-T. Park, H. Sakai, K. Umemori
KEK, Ibaraki, Japan
J. Kamiya, K. Takeishi
JAEA/J-PARC, Tokai-mura, Japan
T. Nagata
ULVAC, Inc., Tsukuba, Japan

KEK has been carrying out SRF cavity developments toward higher Q-values and higher accelerating gradients. In the past nitrogen-doping was tested using the KEK furnaces, but it did not succeed. This time nitrogen infusion and nitrogen doping are tested using the J-PARC's furnace, which has an oil-free pumping system and is mainly pumped by a 10000 L/s cryopump and three 3000 L/s turbo pumps. Nitrogen pressure is controlled by a variable leak valve and an additional turbo pump. To avoid performance degradation during heat treatment, flanges of cavities are covered by Nb caps and foils. Nitrogen infusion at 120 degrees was applied to a single cell cavity and cavity performance was measured by vertical tests after HPR and assembly. Nitrogen doping at 800 degrees is also applied to another single cell cavity. After applying EP and HPR, vertical tests were carried out. Nb samples were also installed into the furnace during heat treatment. Surfaces are analyzed by SIMS and XPS. In this presentation, we report procedure of nitrogen infusion and doping, vertical test results and results of surface analysis.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB021

Export •

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