SRF2021 - List of Authors (Kamigaito, O.)

Paper	Title	Page
MOOFAV01	Successful Beam Commissioning of Heavy-Ion Superconducting Linac at RIKEN	167
	K. Yamada, T. Dantsuka, M. Fujimaki, E. Ikezawa, H. Imao, O. Kamigaito, M. Komiyama, K. Kumagai, T. Nagatomo, T. Nishi, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, A. Uchiyama, T. Watanabe, Y. Watanabe RIKEN Nishina Center, Wako, Japan H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa MHI-MS, Kobe, Japan E. Kako, H. Nakai, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	A new superconducting booster linac, so-called SRILAC, has been constructed at the RIKEN Nishina Center to upgrade the acceleration voltage of the existing linac in order to enable further investigation of new super-heavy elements and the production of useful RIs. The SRILAC consists of 10 TEM quarter-wavelength resonators made from pure niobium sheets which operate at 4.5 K. We succeeded to develop high performance SC-cavities which satisfies the required Q₀ of 1E+9 with a wide margin. Installation of the cryomodule and He refrigerator system was completed by the end of FY2018, and the first cooling test was performed in September 2019. After various tests of the RF system, the beam acceleration was successfully commissioned in January 2020. In June 2020, the beam supply to the experiment was started. In this talk, I will report on the beam commissioning of SRILAC as well as the status of the frequency tuner and the differential pump system.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOOFAV01
About •	Received ※ 26 July 2021 — Revised ※ 30 August 2021 — Accepted ※ 05 March 2022 — Issue date ※ 16 May 2022
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MOPFAV005	Operation Experience of the Superconducting Linac at RIKEN RIBF	315
	N. Sakamoto, H. Imao, O. Kamigaito, T. Nagatomo, T. Nishi, K. Ozeki, K. Suda, A. Uchiyama, K. Yamada RIKEN Nishina Center, Wako, Japan
	After commissioning of the RIKEN superconducting linac (SRILAC) in the end of FY2019, heavy ion beams were provided to the nuclear physics experiments. In this paper operation history and evolution of field emission levels through the year will be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOPFAV005
About •	Received ※ 02 July 2021 — Accepted ※ 27 October 2021 — Issue date ※ 10 April 2022
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WEPTEV013	New Frequency-Tuning System and Digital LLRF for Stable and Reliable Operation of SRILAC	666
	K. Suda, O. Kamigaito, K. Ozeki, N. Sakamoto, K. Yamada RIKEN Nishina Center, Wako, Japan H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa MHI-MS, Kobe, Japan E. Kako, H. Nakai, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	The superconducting booster linac at RIKEN (SRILAC) has ten 73-MHz quarter-wavelength resonators (QWRs) that are contained in three cryomodules. The beam commissioning of SRILAC was successfully performed in January 2020. Frequency tuning during cold operation is performed by compressing the beam port of the cavity with stainless wires and decreasing the length of each beam gap, similar to the method adopted at ANL and FRIB. However, each tuner is driven by a motor connected to gears, instead of using gas pressure. Since the intervals of the QWRs are small due to the beam dynamics, a compact design for the tuner was adopted. Each cavity was tuned to the design frequency, which required frequency changes of 3 kHz to 7 kHz depending on the cavity. Although no piezoelectric actuator is mounted on the tuning system, phase noise caused by microphonics can be sufficiently reduced by a phase-locked loop using a newly developed digital LLRF. The details of the tuning system as well as the digital LLRF will be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPTEV013
About •	Received ※ 13 August 2021 — Revised ※ 13 September 2021 — Accepted ※ 11 November 2021 — Issue date ※ 22 November 2021
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THPTEV001	FPC for RIKEN QWR	825
	K. Ozeki, O. Kamigaito, N. Sakamoto, K. Suda, K. Yamada RIKEN Nishina Center, Wako, Japan
	In RIKEN, three cryomodules which contain ten SC-QWRs in total (4 + 4 + 2) were constructed, and beam supply has been started since last year. The FPCs for RIKEN QWR have a disk-type single vacuum window at room-temperature region. A vacuum leakage occurred at one FPC, after 4th cool-down test. In addition, second vacuum leakage occurred at another FPC, after starting beam supply. A dew condensation at air side of vacuum window may degrade the brazing of vacuum window. In order to prevent a dew condensation and to restore damaged FPCs, an additional outer vacuum window using machinable ceramics was designed and attached to the FPCs. In this contribution, a structure of the FPC, troubles, provision for those troubles, and plan for reconstruction are reported.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPTEV001
About •	Received ※ 22 June 2021 — Revised ※ 26 November 2021 — Accepted ※ 18 January 2022 — Issue date ※ 12 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Successful Beam Commissioning of Heavy-Ion Superconducting Linac at RIKEN

167

K. Yamada, T. Dantsuka, M. Fujimaki, E. Ikezawa, H. Imao, O. Kamigaito, M. Komiyama, K. Kumagai, T. Nagatomo, T. Nishi, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, A. Uchiyama, T. Watanabe, Y. Watanabe
RIKEN Nishina Center, Wako, Japan
H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa
MHI-MS, Kobe, Japan
E. Kako, H. Nakai, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

A new superconducting booster linac, so-called SRILAC, has been constructed at the RIKEN Nishina Center to upgrade the acceleration voltage of the existing linac in order to enable further investigation of new super-heavy elements and the production of useful RIs. The SRILAC consists of 10 TEM quarter-wavelength resonators made from pure niobium sheets which operate at 4.5 K. We succeeded to develop high performance SC-cavities which satisfies the required Q₀ of 1E+9 with a wide margin. Installation of the cryomodule and He refrigerator system was completed by the end of FY2018, and the first cooling test was performed in September 2019. After various tests of the RF system, the beam acceleration was successfully commissioned in January 2020. In June 2020, the beam supply to the experiment was started. In this talk, I will report on the beam commissioning of SRILAC as well as the status of the frequency tuner and the differential pump system.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOOFAV01

About •

Received ※ 26 July 2021 — Revised ※ 30 August 2021 — Accepted ※ 05 March 2022 — Issue date ※ 16 May 2022

Cite •

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

MOPFAV005

Operation Experience of the Superconducting Linac at RIKEN RIBF

315

N. Sakamoto, H. Imao, O. Kamigaito, T. Nagatomo, T. Nishi, K. Ozeki, K. Suda, A. Uchiyama, K. Yamada
RIKEN Nishina Center, Wako, Japan

After commissioning of the RIKEN superconducting linac (SRILAC) in the end of FY2019, heavy ion beams were provided to the nuclear physics experiments. In this paper operation history and evolution of field emission levels through the year will be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOPFAV005

About •

Received ※ 02 July 2021 — Accepted ※ 27 October 2021 — Issue date ※ 10 April 2022

Cite •

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

WEPTEV013

New Frequency-Tuning System and Digital LLRF for Stable and Reliable Operation of SRILAC

666

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

The superconducting booster linac at RIKEN (SRILAC) has ten 73-MHz quarter-wavelength resonators (QWRs) that are contained in three cryomodules. The beam commissioning of SRILAC was successfully performed in January 2020. Frequency tuning during cold operation is performed by compressing the beam port of the cavity with stainless wires and decreasing the length of each beam gap, similar to the method adopted at ANL and FRIB. However, each tuner is driven by a motor connected to gears, instead of using gas pressure. Since the intervals of the QWRs are small due to the beam dynamics, a compact design for the tuner was adopted. Each cavity was tuned to the design frequency, which required frequency changes of 3 kHz to 7 kHz depending on the cavity. Although no piezoelectric actuator is mounted on the tuning system, phase noise caused by microphonics can be sufficiently reduced by a phase-locked loop using a newly developed digital LLRF. The details of the tuning system as well as the digital LLRF will be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPTEV013

About •

Received ※ 13 August 2021 — Revised ※ 13 September 2021 — Accepted ※ 11 November 2021 — Issue date ※ 22 November 2021

Cite •

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

THPTEV001

FPC for RIKEN QWR

825

K. Ozeki, O. Kamigaito, N. Sakamoto, K. Suda, K. Yamada
RIKEN Nishina Center, Wako, Japan

In RIKEN, three cryomodules which contain ten SC-QWRs in total (4 + 4 + 2) were constructed, and beam supply has been started since last year. The FPCs for RIKEN QWR have a disk-type single vacuum window at room-temperature region. A vacuum leakage occurred at one FPC, after 4th cool-down test. In addition, second vacuum leakage occurred at another FPC, after starting beam supply. A dew condensation at air side of vacuum window may degrade the brazing of vacuum window. In order to prevent a dew condensation and to restore damaged FPCs, an additional outer vacuum window using machinable ceramics was designed and attached to the FPCs. In this contribution, a structure of the FPC, troubles, provision for those troubles, and plan for reconstruction are reported.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPTEV001

About •

Received ※ 22 June 2021 — Revised ※ 26 November 2021 — Accepted ※ 18 January 2022 — Issue date ※ 12 May 2022

Cite •

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