SRF2023 - List of Authors (Kako, E.)

Paper	Title	Page
TUPTB018	MgB₂ Coating Parameter Optimization Using a 1.3-GHz 1-Cell Cavity	425
	T. Tajima, T.P. Grumstrup, J.D. Thompson LANL, Los Alamos, New Mexico, USA H. Ito, E. Kako, T. Okada, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	Funding: DOE Office of Science, Office of High Energy Physics We have started parameter optimization for the coating of MgB₂ using a 1-cell 1.3-GHz elliptical cavity with holes for small samples. Our coating method is based on a 2-step technique, i.e., coat a B layer by flowing diborane gas in the first step and react it with Mg vapor in the 2nd step. Three 6 mm x 6 mm B-coated flat samples are attached at inlet, outlet beam pipes, and at a cell equator and reacted with Mg vapor with different parameters and conditions. We started to see the superconducting transitions on samples but Tc is still lower than our goal of >35 K. We will present our current status of B-Mg reaction tests and construction of B coating system.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB018
About •	Received ※ 06 July 2023 — Revised ※ 26 July 2023 — Accepted ※ 02 September 2023 — Issue date ※ 03 September 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB027	Cleanroom Assembly of the LIPAc Cryomodule	452
	J.K. Chambrillon, P. Cara, Y. Carin, G. Duglue, H. Dzitko, D. Gex, G. Phillips, F. Scantamburlo Fusion for Energy, Garching, Germany N. Bazin, N. Chauvin CEA-DRF-IRFU, France Y. Carin, D. Gex, K. Masuda, F. Scantamburlo, M. Sugimoto IFMIF/EVEDA, Rokkasho, Japan T. Ebisawa, K. Hasegawa, K. Kondo, K. Masuda, M. Sugimoto, T.Y. Yanagimachi QST Rokkasho, Aomori, Japan D. Jimenez-Rey, J. Mollá, I. Podadera CIEMAT, Madrid, Spain E. Kako, H. Sakai KEK, Ibaraki, Japan W.-D. Möller Private Address, Hamburg, Germany
	In complement to the development activities for fusion reactors (JT-60SA & ITER), Fusion for Energy contributes to the R&D for material characterisation facilities. LIPAc is the technical demonstrator for the production and acceleration of a D⁺ beam that will be used for neutron production by nuclear stripping reaction on a liquid Li target. Since its first beam in 2014, the LIPAc construction and commissioning continues and will be concluded with the cryomodule installation, aiming for beam validation at nominal power. The cryomodule assembly, started in March 2019, was paused due to welding issues on the solenoid bellows. The slow pumping group used for the cleanroom assembly also needed improvement to overcome helium contamination. Two and half years were devoted to the pumping improvement and, repair, cold tests and high pressure rinsing of the solenoids. In August 2022, the cleanroom assembly resumed with the mounting of all power couplers to the SRF cavities. Despite good progress, the assembly had to be paused again to fix leaks on different vacuum components and a solenoid BPM port. This paper presents the issues faced and their solutions along the cold mass assembly.
	Poster TUPTB027 [2.384 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB027
About •	Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 16 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB029	Measurement of Particulates under Slow Pumping after High Pressure Rinsing of Superconducting Cavity by Using Modified Slow Pumping System	458
	H. Sakai, E. Kako, R. Katayama, K. Umemori KEK, Ibaraki, Japan
	Funding: This research was partially supported by the research fund from Ministry of Education, Culture, Sports, Science and Technology (MEXT). Slow pumping system was used for particle free vacuum pumping in Superconducting rf accelerator. In KEK, recently slow pumping system was developed for the cryomodule assembly work for STF 9-cell cavities and worked well to reduce the particulates movements under pumping. However, this slow pumping system want to be used for preparation of vertical test. Before assembly work in clean room for vertical test, we normally apply high pressure rinsing. There were many waters in the cavity. Therefore, we kept one night to dry inside cavity in clean room. Unfortunately, there were some waters in the cavity even though we kept drying in clean room for one night. This water might make some icing under pumping and stop pumping in mass flow meter, which used for slow pumping to control the mass flow. Therefore, we modify the slow pumping system to be robust under slow pumping even when water exists in the cavity. In this paper, we present the modified slow pumping system in KEK and the results of the vacuum trend through slow pumping of 9-cell superconducting cavity. Under slow pumping, we measure the particulates after high pressure rinsing by using vacuum particle monitor.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB029
About •	Received ※ 16 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 22 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB031	Operational Consideration in the LIPAc SRF with Potential Solenoid Failure Modes	467
	T. Ebisawa, K. Hasegawa, A. Kasugai, K. Kondo, K. Masuda QST Rokkasho, Aomori, Japan Y. Carin, H. Dzitko, D. Gex, G. Phillips F4E, Germany J.K. Chambrillon Fusion for Energy, Garching, Germany N. Chauvin CEA-DRF-IRFU, France E. Kako, H. Sakai KEK, Ibaraki, Japan
	The commissioning of LIPAc (Linear IFMIF Prototype Accelerator) is ongoing at Rokkasho institute of QST for the engineering validation of the accelerator system up to 9 MeV/125 mA. Several SRF cryomodules will be required for IFMIF to accelerate deuterons from 5 MeV to 40 MeV. The prototype of the first of these cryomodules has been manufactured and will be installed and tested on the LIPAc. It holds the eight HWRs (Half Wave Resonator) and RF couplers to accelerate the beam and the eight superconducting solenoids to focus it. During the solenoid HPR process, carried out after fixing welding issues on the solenoid beam line bellows, some concerns appeared about the integrity of two solenoids. The examination with CT scanning of the solenoids revealed that one screw and a few pins had leaved their socket. Although it should be no critical problem, we tried the beam simulation with PIC code TraceWin to determine the location of solenoids whose impact will be minimized to manage in case of failure of solenoid as mitigation action. This paper presents the recommended locations of the suspicious solenoids in the cryomodule and resultant beam conditions through the beam dynamics study.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB031
About •	Received ※ 28 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 07 July 2023 — Issue date ※ 16 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB049	Horizontal Test Results of 1.3 GHz Superconducting RF Gun #2 at KEK	540
	T. Konomi, K. Hara, Y. Honda, K. Hosoyama, H. Inoue, E. Kako, Y. Kondo, M. Masuzawa, M. Omet, T. Takatomi, A. Terashima, K. Tsuchiya, R. Ueki, K. Umemori, X. Wang KEK, Ibaraki, Japan
	Superconducting radio-frequency (SRF) electron guns are attractive for delivery of beams at a high bunch repetition rate with a high accelerating field. KEK has been developing the SRF gun to demonstrate basic performance. The SRF gun consists of 1.3 GHz and 1.5 cell SRF gun cavity and K2CsSb photocathode coated on 2K cathode plug. In the vertical test, the surface peak electric field and the surface peak magnetic field reached to 75 MV/m and 170 mT respectively. The SRF gun was installed to horizontal multipurpose cryostat equipped with a superconducting solenoid, photocathode preparation chamber and beam diagnostic line. The results showed the peak surface electric field degraded to 42 MV/m. We suspect that cavity was contaminated during assembly. In this presentation, we will present the high gradient performance in vertical and horizontal test and individual test for each beam line components.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB049
About •	Received ※ 24 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB062	RF Measurements of the 3rd Harmonic Superconducting Cavity for a Bunch Lengthening	565
	J.Y. Yoon, J.H. Han, H.S. Park, Y.D. Yoon Kiswire Advanced Technology Ltd., Daejeon, Republic of Korea E. Kako KEK, Ibaraki, Japan E.-S. Kim Korea University Sejong Campus, Sejong, Republic of Korea
	The brightness can be increased by minimizing the emittance in the light source, but the reduced emittance also increases the number of collisions of electrons in the beam bunch. Therefore, the bunch lengthening by using the 3rd harmonic cavity reduces the collisions of electrons and increases the Touschek lifetime. Since the resonant frequency of the main RF cavity is 500 MHz, the resonant frequency of 3rd harmonic cavity is selected as 1500 MHz. The prototype cavity is a passive type in which a power coupler is not used, and power is supplied from the beam. The operating temperature is 4.5 K, which is a superconducting cavity. The elliptical double-cell geometry was selected to increase the accelerating voltage of the cavity and reduce power losses. Based on this design, three niobium cavities are fabricated and tested. In this paper, we present the RF measurement results of the 3rd harmonic cavity at room temperature. 3rd harmonic cavity 4th generation storage ring
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB062
About •	Received ※ 12 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB083	Basic Design and Consideration of Li-Vapor Contamination for A-FNS SRF	773
	T. Ebisawa, K. Hasegawa, A. Kasugai, M. Oyaidzu, S. Sato QST Rokkasho, Aomori, Japan E. Kako, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	The Advanced Fusion Neutron Source (A-FNS) project is in progressing in Japan, QST Rokkasho institute. A-FNS will demonstrate a performance of the DEMO DT fusion reactor material. In order to perform the test, a high intensity deuteron beam accelerator will be used to produce a high flux neutron field which is similar to the 14 MeV DT neutron. The Superconducting Radio-Frequency linear accelerator (SRF) is one component of the A-FNS accelerator system. Although the A-FNS accelerator system design is based on the IFMIF design, the improvement of some subsystem has been considering by taking into account the lessons learnt from the LIPAc project. In order to keep a high stability and availability of the SRF performance, we plan to increase the number of SRF cavities and cryomodules considering the trouble or degradation of the cavity performance and modify the engineering design of some components. In addition, changing of the beam transport line design and Li vapor contamination study of SRF cavity are conducting. In this presentation, the progress of the SRF design and related activities for A-FNS in QST will be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB083
About •	Received ※ 28 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 17 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THCAA01	Development of Single-spoke Cavities for ADS at JAEA	947
	Y. Kondo JAEA, Ibaraki-ken, Japan T. Dohmae, E. Kako, H. Sakai, K. Umemori KEK, Ibaraki, Japan F. Maekawa, S.I. Meigo, J. Tamura, B. Yee-Rendón JAEA/J-PARC, Tokai-mura, Japan
	Japan Atomic Energy Agency (JAEA) has been proposing an accelerator-driven system (ADS) as a future nuclear system to efficiently reduce the high-level radioactive waste generated at nuclear power plants. As the first step toward the full-scale CW proton linac for the JAEA-ADS, we are now prototyping a low-beta (around 0.2) single-spoke cavity. Because there is no experience in manufacturing superconducting spoke cavities in Japan, prototyping and performance testing of the cavity are essential to ensure the feasibility of the JAEA-ADS. The dimensional parameters of the prototype spoke cavity were optimized to obtain higher cavity performance. The actual cavity fabrication started in 2020. Most of the cavity parts were fabricated in fiscal year 2020 by press-forming and machining. In 2021, we started welding the cavity parts together. After investigating the optimum welding conditions using mock-up test pieces, each cavity part was joined with smooth welding beads. Currently, the cavity’s body section and the beam port sections have been assembled. This paper presents the current status of the JAEA-ADS and it’s cavity prototyping.
	Slides THCAA01 [8.433 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-THCAA01
About •	Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 10 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MgB₂ Coating Parameter Optimization Using a 1.3-GHz 1-Cell Cavity

425

T. Tajima, T.P. Grumstrup, J.D. Thompson
LANL, Los Alamos, New Mexico, USA
H. Ito, E. Kako, T. Okada, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

Funding: DOE Office of Science, Office of High Energy Physics
We have started parameter optimization for the coating of MgB₂ using a 1-cell 1.3-GHz elliptical cavity with holes for small samples. Our coating method is based on a 2-step technique, i.e., coat a B layer by flowing diborane gas in the first step and react it with Mg vapor in the 2nd step. Three 6 mm x 6 mm B-coated flat samples are attached at inlet, outlet beam pipes, and at a cell equator and reacted with Mg vapor with different parameters and conditions. We started to see the superconducting transitions on samples but Tc is still lower than our goal of >35 K. We will present our current status of B-Mg reaction tests and construction of B coating system.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB018

About •

Received ※ 06 July 2023 — Revised ※ 26 July 2023 — Accepted ※ 02 September 2023 — Issue date ※ 03 September 2023

Cite •

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

TUPTB027

Cleanroom Assembly of the LIPAc Cryomodule

452

J.K. Chambrillon, P. Cara, Y. Carin, G. Duglue, H. Dzitko, D. Gex, G. Phillips, F. Scantamburlo
Fusion for Energy, Garching, Germany
N. Bazin, N. Chauvin
CEA-DRF-IRFU, France
Y. Carin, D. Gex, K. Masuda, F. Scantamburlo, M. Sugimoto
IFMIF/EVEDA, Rokkasho, Japan
T. Ebisawa, K. Hasegawa, K. Kondo, K. Masuda, M. Sugimoto, T.Y. Yanagimachi
QST Rokkasho, Aomori, Japan
D. Jimenez-Rey, J. Mollá, I. Podadera
CIEMAT, Madrid, Spain
E. Kako, H. Sakai
KEK, Ibaraki, Japan
W.-D. Möller
Private Address, Hamburg, Germany

In complement to the development activities for fusion reactors (JT-60SA & ITER), Fusion for Energy contributes to the R&D for material characterisation facilities. LIPAc is the technical demonstrator for the production and acceleration of a D⁺ beam that will be used for neutron production by nuclear stripping reaction on a liquid Li target. Since its first beam in 2014, the LIPAc construction and commissioning continues and will be concluded with the cryomodule installation, aiming for beam validation at nominal power. The cryomodule assembly, started in March 2019, was paused due to welding issues on the solenoid bellows. The slow pumping group used for the cleanroom assembly also needed improvement to overcome helium contamination. Two and half years were devoted to the pumping improvement and, repair, cold tests and high pressure rinsing of the solenoids. In August 2022, the cleanroom assembly resumed with the mounting of all power couplers to the SRF cavities. Despite good progress, the assembly had to be paused again to fix leaks on different vacuum components and a solenoid BPM port. This paper presents the issues faced and their solutions along the cold mass assembly.

Poster TUPTB027 [2.384 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB027

About •

Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 16 July 2023

Cite •

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

TUPTB029

Measurement of Particulates under Slow Pumping after High Pressure Rinsing of Superconducting Cavity by Using Modified Slow Pumping System

458

H. Sakai, E. Kako, R. Katayama, K. Umemori
KEK, Ibaraki, Japan

Funding: This research was partially supported by the research fund from Ministry of Education, Culture, Sports, Science and Technology (MEXT).
Slow pumping system was used for particle free vacuum pumping in Superconducting rf accelerator. In KEK, recently slow pumping system was developed for the cryomodule assembly work for STF 9-cell cavities and worked well to reduce the particulates movements under pumping. However, this slow pumping system want to be used for preparation of vertical test. Before assembly work in clean room for vertical test, we normally apply high pressure rinsing. There were many waters in the cavity. Therefore, we kept one night to dry inside cavity in clean room. Unfortunately, there were some waters in the cavity even though we kept drying in clean room for one night. This water might make some icing under pumping and stop pumping in mass flow meter, which used for slow pumping to control the mass flow. Therefore, we modify the slow pumping system to be robust under slow pumping even when water exists in the cavity. In this paper, we present the modified slow pumping system in KEK and the results of the vacuum trend through slow pumping of 9-cell superconducting cavity. Under slow pumping, we measure the particulates after high pressure rinsing by using vacuum particle monitor.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB029

About •

Received ※ 16 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 22 August 2023

Cite •

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

TUPTB031

Operational Consideration in the LIPAc SRF with Potential Solenoid Failure Modes

467

T. Ebisawa, K. Hasegawa, A. Kasugai, K. Kondo, K. Masuda
QST Rokkasho, Aomori, Japan
Y. Carin, H. Dzitko, D. Gex, G. Phillips
F4E, Germany
J.K. Chambrillon
Fusion for Energy, Garching, Germany
N. Chauvin
CEA-DRF-IRFU, France
E. Kako, H. Sakai
KEK, Ibaraki, Japan

The commissioning of LIPAc (Linear IFMIF Prototype Accelerator) is ongoing at Rokkasho institute of QST for the engineering validation of the accelerator system up to 9 MeV/125 mA. Several SRF cryomodules will be required for IFMIF to accelerate deuterons from 5 MeV to 40 MeV. The prototype of the first of these cryomodules has been manufactured and will be installed and tested on the LIPAc. It holds the eight HWRs (Half Wave Resonator) and RF couplers to accelerate the beam and the eight superconducting solenoids to focus it. During the solenoid HPR process, carried out after fixing welding issues on the solenoid beam line bellows, some concerns appeared about the integrity of two solenoids. The examination with CT scanning of the solenoids revealed that one screw and a few pins had leaved their socket. Although it should be no critical problem, we tried the beam simulation with PIC code TraceWin to determine the location of solenoids whose impact will be minimized to manage in case of failure of solenoid as mitigation action. This paper presents the recommended locations of the suspicious solenoids in the cryomodule and resultant beam conditions through the beam dynamics study.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB031

About •

Received ※ 28 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 07 July 2023 — Issue date ※ 16 July 2023

Cite •

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

TUPTB049

Horizontal Test Results of 1.3 GHz Superconducting RF Gun #2 at KEK

540

T. Konomi, K. Hara, Y. Honda, K. Hosoyama, H. Inoue, E. Kako, Y. Kondo, M. Masuzawa, M. Omet, T. Takatomi, A. Terashima, K. Tsuchiya, R. Ueki, K. Umemori, X. Wang
KEK, Ibaraki, Japan

Superconducting radio-frequency (SRF) electron guns are attractive for delivery of beams at a high bunch repetition rate with a high accelerating field. KEK has been developing the SRF gun to demonstrate basic performance. The SRF gun consists of 1.3 GHz and 1.5 cell SRF gun cavity and K2CsSb photocathode coated on 2K cathode plug. In the vertical test, the surface peak electric field and the surface peak magnetic field reached to 75 MV/m and 170 mT respectively. The SRF gun was installed to horizontal multipurpose cryostat equipped with a superconducting solenoid, photocathode preparation chamber and beam diagnostic line. The results showed the peak surface electric field degraded to 42 MV/m. We suspect that cavity was contaminated during assembly. In this presentation, we will present the high gradient performance in vertical and horizontal test and individual test for each beam line components.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB049

About •

Received ※ 24 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023

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

TUPTB062

RF Measurements of the 3rd Harmonic Superconducting Cavity for a Bunch Lengthening

565

J.Y. Yoon, J.H. Han, H.S. Park, Y.D. Yoon
Kiswire Advanced Technology Ltd., Daejeon, Republic of Korea
E. Kako
KEK, Ibaraki, Japan
E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea

The brightness can be increased by minimizing the emittance in the light source, but the reduced emittance also increases the number of collisions of electrons in the beam bunch. Therefore, the bunch lengthening by using the 3rd harmonic cavity reduces the collisions of electrons and increases the Touschek lifetime. Since the resonant frequency of the main RF cavity is 500 MHz, the resonant frequency of 3rd harmonic cavity is selected as 1500 MHz. The prototype cavity is a passive type in which a power coupler is not used, and power is supplied from the beam. The operating temperature is 4.5 K, which is a superconducting cavity. The elliptical double-cell geometry was selected to increase the accelerating voltage of the cavity and reduce power losses. Based on this design, three niobium cavities are fabricated and tested. In this paper, we present the RF measurement results of the 3rd harmonic cavity at room temperature.
*3rd harmonic cavity
*4th generation storage ring

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB062

About •

Received ※ 12 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023

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

WEPWB083

Basic Design and Consideration of Li-Vapor Contamination for A-FNS SRF

773

T. Ebisawa, K. Hasegawa, A. Kasugai, M. Oyaidzu, S. Sato
QST Rokkasho, Aomori, Japan
E. Kako, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

The Advanced Fusion Neutron Source (A-FNS) project is in progressing in Japan, QST Rokkasho institute. A-FNS will demonstrate a performance of the DEMO DT fusion reactor material. In order to perform the test, a high intensity deuteron beam accelerator will be used to produce a high flux neutron field which is similar to the 14 MeV DT neutron. The Superconducting Radio-Frequency linear accelerator (SRF) is one component of the A-FNS accelerator system. Although the A-FNS accelerator system design is based on the IFMIF design, the improvement of some subsystem has been considering by taking into account the lessons learnt from the LIPAc project. In order to keep a high stability and availability of the SRF performance, we plan to increase the number of SRF cavities and cryomodules considering the trouble or degradation of the cavity performance and modify the engineering design of some components. In addition, changing of the beam transport line design and Li vapor contamination study of SRF cavity are conducting. In this presentation, the progress of the SRF design and related activities for A-FNS in QST will be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB083

About •

Received ※ 28 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 17 August 2023

Cite •

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

THCAA01

Development of Single-spoke Cavities for ADS at JAEA

947

Y. Kondo
JAEA, Ibaraki-ken, Japan
T. Dohmae, E. Kako, H. Sakai, K. Umemori
KEK, Ibaraki, Japan
F. Maekawa, S.I. Meigo, J. Tamura, B. Yee-Rendón
JAEA/J-PARC, Tokai-mura, Japan

Japan Atomic Energy Agency (JAEA) has been proposing an accelerator-driven system (ADS) as a future nuclear system to efficiently reduce the high-level radioactive waste generated at nuclear power plants. As the first step toward the full-scale CW proton linac for the JAEA-ADS, we are now prototyping a low-beta (around 0.2) single-spoke cavity. Because there is no experience in manufacturing superconducting spoke cavities in Japan, prototyping and performance testing of the cavity are essential to ensure the feasibility of the JAEA-ADS. The dimensional parameters of the prototype spoke cavity were optimized to obtain higher cavity performance. The actual cavity fabrication started in 2020. Most of the cavity parts were fabricated in fiscal year 2020 by press-forming and machining. In 2021, we started welding the cavity parts together. After investigating the optimum welding conditions using mock-up test pieces, each cavity part was joined with smooth welding beads. Currently, the cavity’s body section and the beam port sections have been assembled. This paper presents the current status of the JAEA-ADS and it’s cavity prototyping.

Slides THCAA01 [8.433 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-THCAA01

About •

Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 10 July 2023

Cite •

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