LINAC2018 - List of Authors (Kako, E.)

Paper	Title	Page
TUPO052	Design Study of a Prototype 325MHz RF Power Coupler for Superconducting Cavity	451
	J.Y. Yoon, J.B. Bhang, H.J. Cha, S.W. Jang, E.-S. Kim, K.R. Kim, C.S. Park, S. H. Park Korea University Sejong Campus, Sejong, Republic of Korea E. Kako KEK, Ibaraki, Japan D.Y. Kim, J. Lee Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea I. Shin IBS, Daejeon, Republic of Korea
	Funding: Korea University (Sejong Campus) in South KOREA We present design studies of a prototype RF input power coupler, which provides RF powers to 325MHz cavities up to 18.5 kW in CW mode. The prototype power coupler is a coaxial capacitive type with single ceramic window. In order to optimize the RF coupler design, we performed multi-physics simulations, including electromagnetic, thermal, and mechanical analyses.
	Poster TUPO052 [1.607 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO052
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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)

TUPO070	Design and Commissioning of KEK New Vacuum Furnace for SRF Cavity Development	496
	K. Umemori, M. Egi, E. Kako, T. Konomi, S. Michizono, H. Sakai KEK, Ibaraki, Japan
	Recently new techniques such as Nitrogen-doping and Nitrogen-infusion have been developed to improve performance of SRF (Superconducting RF) cavities. We purchased a new vacuum furnace, which is key to realize these techniques. Cleanness of the furnace is most important issue. The furnace has a cryo-pump and whole of vacuum system is oil-free system. Target vacuum level after cooling down is 1x10^-6 Pa. Heater, reflectors and support table were made from Molybdenum to avoid contamination during heat treatment. Metal gaskets are used for all vacuum seals, except big doors. Maximum operation temperature is 1150 degree C. Size is around 1 m diameter and 2m long for a 1.3 GHz 9-cell cavity. Entrance of furnace is covered by a clean booth. The furnace was fabricated, assembled at KEK COI building and commissioned this year. After several burning runs, target vacuum pressure was achieved after cooling down to room temperature. Design of the furnace and performance during commissioning runs are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO070
About •	paper received ※ 19 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)

TUPO072	First Trial of the In-situ Nitrogen Infusion at KEK	503
	T. Konomi, T. Dohmae, E. Kako, S. Michizono, H. Sakai, K. Umemori KEK, Ibaraki, Japan T. Okada Sokendai, Ibaraki, Japan
	The nitrogen infusion is the new surface treatment technique for improving the RF loss and the maximum accelerating gradient of superconducting cavity. In this process, it is important to be carried out continuously both the 800 C annealing in vacuum and 120 C nitrogen infusion without exposure to the atmosphere. The annealing serves activation process by removing the oxide layer. The in-situ nitrogen infusion system was prepared to investigate whether nitrogen infusion effect or something changes happen in the case of applying nitrogen infusion technique without removing the oxide layer. It can only introduce nitrogen into a cavity during 120 C low temperature baking and transport a cavity to the vertical test system without exposure to the atmosphere. We tried to infuse nitrogen to a single cell by keeping 120 C and 48 hours with 3 Pa nitrogen. The cavity was annealed in another furnace and applied high pressure rinsing before nitrogen infusion. The vertical test result was same Q as the normal 120 C baking without nitrogen. It suggests that oxide layer prevents infusion of nitrogen. In this poster, the in-situ nitrogen infusion system and vertical test results will be reported.
	Poster TUPO072 [4.653 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO072
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)

TUPO073	Niobium Sample Analysis for Nitrogen Infusion and Doping	506
	T. Konomi, E. Kako, S. Michizono, H. Sakai, K. Umemori KEK, Ibaraki, Japan T. Nagata ULVAC, Inc., Tsukuba, Japan T. Nojima Tohoku University, Sendai, Japan
	KEK has been investigating the better conditions of the heat treatment in nitrogen, which are called as nitrogen doping and nitrogen infusion. We have tried to understand the high gradient performance of the cavity from the analyses of samples which were prepared in the same conditions for the cavity. The main tools are D-SIMS for the depth profile of the elemental concentration, XPS for composition analysis and SQUID magnetometry for the critical DC magnetic field measurement. The difference in the depth profiles of the nitrogen, carbon and oxygen between the heat treatment conditions was observed in vacuum and furnace temperature of nitrogen infusion by D-SIMS and XPS. Such a difference correlates with the vortex penetration field measured by SQUID. In particular, that of nitrogen doping sample was greatly degraded, while that of nitrogen infusion sample was slightly improved. The tendency is similar to the RF high gradient test results. Details of the sample analysis are shown in this presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO073
About •	paper received ※ 18 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)

TUPO074	Design and Fabrication of KEK Superconducting RF Gun #2	510
	T. Konomi, Y. Honda, E. Kako, Y. Kobayashi, S. Michizono, T. Miyajima, H. Sakai, K. Umemori, S. Yamaguchi, M. Yamamoto KEK, Ibaraki, Japan
	Superconducting RF gun can realize high acceleration voltage and high beam repetition. KEK has been developing the 1.3 GHz elliptical type 1.5 cell superconducting RF gun to investigate fundamental performance. A surface cleaning method and tools are developed by using KEK SRFGUN #1 and high surface peak gradient 75 MV/m was achieved without field emission. SRFGUN #2 which equips the helium jacket and can be operated with electron beam was designed based on the SRFGUN #1. It can be operated with transmit type photocathode which include superconducting transparent material. The cathode plug is cooled by thermal conducting from the 2 K helium jacket and photocathode will be kept around 2K to maintain superconductivity. Bulk niobium photocathode plug and substrate will used for the fundamental performance test. In parallel, the photocathode deposition chamber for multi-alkali photocathode will be prepared.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO074
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)

WE2A03	Construction Status of the Superconducting Linac at RIKEN RIBF	620
	N. Sakamoto, H. Imao, O. Kamigaito, K. Kusaka, H. Okuno, K. Ozeki, K. Suda, T. Watanabe, Y. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan H. Hara, T. Yanagisawa MHI, Hiroshima, Japan E. Kako, H. Nakai, H. Sakai, K. Umemori KEK, Ibaraki, Japan A. Miyamoto, K. Sennyu MHI-MS, Kobe, Japan
	An upgrade project of the RIKEN Heavy-Ion Linac, RILAC, is under going, which aims at the further investigation of the super-heavy elements and production of radioactive isotopes for medical applications. In this project, a new superconducting ECR ion source and superconducting RF (SRF) booster linac are being developed and constructed. The SRF linac consists of 10 quarter-wavelength resonator operated at 73 MHz, that are contained in three cryomodules. The construction status, including the first vertical test results, will be given in this paper.
	Slides WE2A03 [23.169 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A03
About •	paper received ※ 14 September 2018 paper accepted ※ 17 October 2018 issue date ※ 18 January 2019
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THPO008	Long-term 0peration with Beam and Cavity Performance Degradation in Compact-ERL Main Linac at KEK	695
	H. Sakai, T. Furuya, E. Kako, T. Konomi, T. Miura, F. Qiu, K. Umemori KEK, Ibaraki, Japan
	We developed ERL main linac cryomodule for Compact ERL (cERL) in KEK. The module consists of two 9-cell 1.3 GHz superconducting cavities. After construction of cERL recirculation loop, beam operation was started in 2013 Dec. First electron beam of 20 MeV successfully passed the main linac cavities. Beam current increased step by step and currently reached to 1mA (CW). Energy recovery has successfully achieved. However, field emission was one of the problems for long term operation. Therefore, the performance of the SRF cavities through long term beam operation has been investigated. In this paper, we express the measurement of the cavity performances and its degradation during long term beam operation. We also described the details of the cavity performance degradation and some trial for the cavity performance recovery.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO008
About •	paper received ※ 11 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

Design Study of a Prototype 325MHz RF Power Coupler for Superconducting Cavity

451

J.Y. Yoon, J.B. Bhang, H.J. Cha, S.W. Jang, E.-S. Kim, K.R. Kim, C.S. Park, S. H. Park
Korea University Sejong Campus, Sejong, Republic of Korea
E. Kako
KEK, Ibaraki, Japan
D.Y. Kim, J. Lee
Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea
I. Shin
IBS, Daejeon, Republic of Korea

Funding: Korea University (Sejong Campus) in South KOREA
We present design studies of a prototype RF input power coupler, which provides RF powers to 325MHz cavities up to 18.5 kW in CW mode. The prototype power coupler is a coaxial capacitive type with single ceramic window. In order to optimize the RF coupler design, we performed multi-physics simulations, including electromagnetic, thermal, and mechanical analyses.

Poster TUPO052 [1.607 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO052

About •

paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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

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

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

TUPO070

Design and Commissioning of KEK New Vacuum Furnace for SRF Cavity Development

496

K. Umemori, M. Egi, E. Kako, T. Konomi, S. Michizono, H. Sakai
KEK, Ibaraki, Japan

Recently new techniques such as Nitrogen-doping and Nitrogen-infusion have been developed to improve performance of SRF (Superconducting RF) cavities. We purchased a new vacuum furnace, which is key to realize these techniques. Cleanness of the furnace is most important issue. The furnace has a cryo-pump and whole of vacuum system is oil-free system. Target vacuum level after cooling down is 1x10^-6 Pa. Heater, reflectors and support table were made from Molybdenum to avoid contamination during heat treatment. Metal gaskets are used for all vacuum seals, except big doors. Maximum operation temperature is 1150 degree C. Size is around 1 m diameter and 2m long for a 1.3 GHz 9-cell cavity. Entrance of furnace is covered by a clean booth. The furnace was fabricated, assembled at KEK COI building and commissioned this year. After several burning runs, target vacuum pressure was achieved after cooling down to room temperature. Design of the furnace and performance during commissioning runs are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO070

About •

paper received ※ 19 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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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)

TUPO072

First Trial of the In-situ Nitrogen Infusion at KEK

503

T. Konomi, T. Dohmae, E. Kako, S. Michizono, H. Sakai, K. Umemori
KEK, Ibaraki, Japan
T. Okada
Sokendai, Ibaraki, Japan

The nitrogen infusion is the new surface treatment technique for improving the RF loss and the maximum accelerating gradient of superconducting cavity. In this process, it is important to be carried out continuously both the 800 C annealing in vacuum and 120 C nitrogen infusion without exposure to the atmosphere. The annealing serves activation process by removing the oxide layer. The in-situ nitrogen infusion system was prepared to investigate whether nitrogen infusion effect or something changes happen in the case of applying nitrogen infusion technique without removing the oxide layer. It can only introduce nitrogen into a cavity during 120 C low temperature baking and transport a cavity to the vertical test system without exposure to the atmosphere. We tried to infuse nitrogen to a single cell by keeping 120 C and 48 hours with 3 Pa nitrogen. The cavity was annealed in another furnace and applied high pressure rinsing before nitrogen infusion. The vertical test result was same Q as the normal 120 C baking without nitrogen. It suggests that oxide layer prevents infusion of nitrogen. In this poster, the in-situ nitrogen infusion system and vertical test results will be reported.

Poster TUPO072 [4.653 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO072

About •

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

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TUPO073

Niobium Sample Analysis for Nitrogen Infusion and Doping

506

T. Konomi, E. Kako, S. Michizono, H. Sakai, K. Umemori
KEK, Ibaraki, Japan
T. Nagata
ULVAC, Inc., Tsukuba, Japan
T. Nojima
Tohoku University, Sendai, Japan

KEK has been investigating the better conditions of the heat treatment in nitrogen, which are called as nitrogen doping and nitrogen infusion. We have tried to understand the high gradient performance of the cavity from the analyses of samples which were prepared in the same conditions for the cavity. The main tools are D-SIMS for the depth profile of the elemental concentration, XPS for composition analysis and SQUID magnetometry for the critical DC magnetic field measurement. The difference in the depth profiles of the nitrogen, carbon and oxygen between the heat treatment conditions was observed in vacuum and furnace temperature of nitrogen infusion by D-SIMS and XPS. Such a difference correlates with the vortex penetration field measured by SQUID. In particular, that of nitrogen doping sample was greatly degraded, while that of nitrogen infusion sample was slightly improved. The tendency is similar to the RF high gradient test results. Details of the sample analysis are shown in this presentation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO073

About •

paper received ※ 18 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)

TUPO074

Design and Fabrication of KEK Superconducting RF Gun #2

510

T. Konomi, Y. Honda, E. Kako, Y. Kobayashi, S. Michizono, T. Miyajima, H. Sakai, K. Umemori, S. Yamaguchi, M. Yamamoto
KEK, Ibaraki, Japan

Superconducting RF gun can realize high acceleration voltage and high beam repetition. KEK has been developing the 1.3 GHz elliptical type 1.5 cell superconducting RF gun to investigate fundamental performance. A surface cleaning method and tools are developed by using KEK SRFGUN #1 and high surface peak gradient 75 MV/m was achieved without field emission. SRFGUN #2 which equips the helium jacket and can be operated with electron beam was designed based on the SRFGUN #1. It can be operated with transmit type photocathode which include superconducting transparent material. The cathode plug is cooled by thermal conducting from the 2 K helium jacket and photocathode will be kept around 2K to maintain superconductivity. Bulk niobium photocathode plug and substrate will used for the fundamental performance test. In parallel, the photocathode deposition chamber for multi-alkali photocathode will be prepared.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO074

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

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

WE2A03

Construction Status of the Superconducting Linac at RIKEN RIBF

620

N. Sakamoto, H. Imao, O. Kamigaito, K. Kusaka, H. Okuno, K. Ozeki, K. Suda, T. Watanabe, Y. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
H. Hara, T. Yanagisawa
MHI, Hiroshima, Japan
E. Kako, H. Nakai, H. Sakai, K. Umemori
KEK, Ibaraki, Japan
A. Miyamoto, K. Sennyu
MHI-MS, Kobe, Japan

An upgrade project of the RIKEN Heavy-Ion Linac, RILAC, is under going, which aims at the further investigation of the super-heavy elements and production of radioactive isotopes for medical applications. In this project, a new superconducting ECR ion source and superconducting RF (SRF) booster linac are being developed and constructed. The SRF linac consists of 10 quarter-wavelength resonator operated at 73 MHz, that are contained in three cryomodules. The construction status, including the first vertical test results, will be given in this paper.

Slides WE2A03 [23.169 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A03

About •

paper received ※ 14 September 2018 paper accepted ※ 17 October 2018 issue date ※ 18 January 2019

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THPO008

Long-term 0peration with Beam and Cavity Performance Degradation in Compact-ERL Main Linac at KEK

695

H. Sakai, T. Furuya, E. Kako, T. Konomi, T. Miura, F. Qiu, K. Umemori
KEK, Ibaraki, Japan

We developed ERL main linac cryomodule for Compact ERL (cERL) in KEK. The module consists of two 9-cell 1.3 GHz superconducting cavities. After construction of cERL recirculation loop, beam operation was started in 2013 Dec. First electron beam of 20 MeV successfully passed the main linac cavities. Beam current increased step by step and currently reached to 1mA (CW). Energy recovery has successfully achieved. However, field emission was one of the problems for long term operation. Therefore, the performance of the SRF cavities through long term beam operation has been investigated. In this paper, we express the measurement of the cavity performances and its degradation during long term beam operation. We also described the details of the cavity performance degradation and some trial for the cavity performance recovery.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO008

About •

paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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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)