TY  - CONF
AU  - Wei, J.
AU  - Ao, H.
AU  - Arend, B.
AU  - Beher, S.
AU  - Bollen, G.
AU  - Bultman, N.K.
AU  - Casagrande, F.
AU  - Chang, W.
AU  - Choi, Y.
AU  - Cogan, S.
AU  - Compton, C.
AU  - Cortesi, M.
AU  - Curtin, J.C.
AU  - Davidson, K.D.
AU  - Du, X.J.
AU  - Elliott, K.
AU  - Ewert, B.
AU  - Facco, A.
AU  - Fila, A.
AU  - Fukushima, K.
AU  - Ganni, V.
AU  - Ganshyn, A.
AU  - Ginter, T.N.
AU  - Glasmacher, T.
AU  - Guo, J.-W.
AU  - Hao, Y.
AU  - Hartung, W.
AU  - Hasan, N.M.
AU  - Hausmann, M.
AU  - Holland, K.
AU  - Hosoyama, K.
AU  - Hseuh, H.-C.
AU  - Hurh, P.
AU  - Ikegami, M.
AU  - Jager, D.D.
AU  - Jones, S.
AU  - Joseph, N.
AU  - Kanemura, T.
AU  - Kelly, M.P.
AU  - Kim, S.H.
AU  - Knowles, C.
AU  - Konomi, T.
AU  - Kortum, B.R.
AU  - Kwan, E.
AU  - Lange, T.
AU  - Larmann, M.
AU  - Larter, T.L.
AU  - Laturkar, K.
AU  - Laxdal, R.E.
AU  - LeTourneau, J.
AU  - Li, Z.
AU  - Lidia, S.M.
AU  - Machicoane, G.
AU  - Magsig, C.
AU  - Manwiller, P.E.
AU  - Marti, F.
AU  - Maruta, T.
AU  - Metzgar, E.S.
AU  - Miller, S.J.
AU  - Momozaki, Y.
AU  - Morris, D.G.
AU  - Mugerian, M.
AU  - Nesterenko, I.N.
AU  - Nguyen, C.
AU  - Ostroumov, P.N.
AU  - Patil, M.S.
AU  - Plastun, A.S.
AU  - Popielarski, L.
AU  - Portillo, M.
AU  - Prestemon, S.O.
AU  - Priller, J.
AU  - Rao, X.
AU  - Reaume, M.A.
AU  - Saito, K.
AU  - Sherrill, B.M.
AU  - Smith, M.K.
AU  - Song, J.
AU  - Steiner, M.
AU  - Stolz, A.
AU  - Tarasov, O.
AU  - Tousignant, B.P.
AU  - Walker, R.
AU  - Wang, X.
AU  - Wenstrom, J.D.
AU  - West, G.
AU  - Wiseman, M.
AU  - Witgen, K.
AU  - Wright, M.
AU  - Xu, T.
AU  - Yamazaki, Y.
AU  - Zhang, T.
AU  - Zhao, Q.
AU  - Zhao, S.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - FRIB Transition to User Operations, Power Ramp Up, and Upgrade Perspectives
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - After project completion on scope, on cost, and ahead of schedule, the Facility for Rare Isotope Beams began operations for scientific users in May of 2022. During the first 12 months of user operations, the FRIB accelerator complex delivered 5250 beam hours, including 1528 hours to nine science experiments conducted with primary beams of 36Ar, 48Ca, 70Zn, 82Se, 124Xe, and 198Pt at beam energies >200 MeV/u; 2724 hours for beam developments, studies, and tuning; and 998 hours to industrial users and non-scientific programs using the FRIB Single Event Effect (FSEE) beam line. The ramp-up to a beam power of 400 kW is planned over a six-year period; 1 kW was delivered for initial user runs from in 2022, and 5 kW was delivered as of February 2023. Upgrade plans include doubling the primary-beam energy to 400 MeV/nucleon for enhanced discovery potential (¿FRIB 400¿). This talk reports on FRIB status and progress since SRF2021, emphasizing lessons learned during the transition from beam commissioning to machine operations, challenges and resolutions for the power ramp-up, progress with accelerator improvements, and R&D for the energy upgrade.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 1
EP  - 8
KW  - cavity
KW  - cryomodule
KW  - operation
KW  - linac
KW  - target
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOIAA01
UR  - https://jacow.org/srf2023/papers/moiaa01.pdf
ER  - 

TY  - CONF
AU  - Nishiwaki, M.
AU  - Akai, K.
AU  - Furuya, T.
AU  - Mitsunobu, S.
AU  - Morita, Y.
AU  - Okada, T.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Operating Experience of SRF System at High Beam Current in SuperKEKB
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - SuperKEKB aims for high luminosity on the order of 10³⁵ cm⁻²s⁻¹ with beam currents of 2.6 A for electron and 3.6 A for positron to search new physics beyond the Standard Model in the B meson regime. In recent operations, we achieved a new record of luminosity of 4.65×10³⁴ cm⁻²s⁻¹ with 1.1 A for electron and 1.3 A for positron. The SRF system that was designed for KEKB, the predecessor of SuperKEKB, is operating stably with the high beam currents owing to the measures against the large beam powers and the large higher-order-mode (HOM) powers. As a measure against the large beam powers, our SRF cavities have increased a coupling of high-power input couplers during the KEKB operation. As a measure against the large HOM power, newly developed SiC HOM dampers have been installed in the SuperKEKB ring. In addition, we have established the horizontal high-pressure rinse method to recover the cavity performance that has degraded due to vacuum works and accidents in the long-term operation. In this report, we will present our operation experience of SRF system under the high beam currents.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 38
EP  - 42
KW  - cavity
KW  - operation
KW  - HOM
KW  - SRF
KW  - luminosity
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOIXA05
UR  - https://jacow.org/srf2023/papers/moixa05.pdf
ER  - 

TY  - CONF
AU  - Omet, M.
AU  - Araki, H.
AU  - Dohmae, T.
AU  - Ito, H.
AU  - Katayama, R.
AU  - Umemori, K.
AU  - Yamamoto, Y.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Efforts to Suppress Field Emission in SRF Cavities at KEK
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Our main objective is to achieve as high as possible quality factors Q₀ and maximal accelerating voltages E_{acc} within 1.3 GHz superconducting radio frequency (SRF) cavities. Beside an adequate surface treatment, key to achieve good performance is a proper assembly in the clean room prior cavity testing or operation. In this contribution we present the methods and results of our efforts to get a better understanding of our clean room environment and the particulate generation caused during the assembly work. Furthermore, we present the measures taken to suppress filed emission, followed by an analysis of vertical test results of the last six years.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 167
EP  - 171
KW  - cavity
KW  - SRF
KW  - laser
KW  - acceleration
KW  - site
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB033
UR  - https://jacow.org/srf2023/papers/mopmb033.pdf
ER  - 

TY  - CONF
AU  - Okada, T.
AU  - Akai, K.
AU  - Furuya, T.
AU  - Mitsunobu, S.
AU  - Morita, Y.
AU  - Nishiwaki, M.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Loading Test of Hom Dampers for Superconducting Cavities for High Current at Superkekb
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - SuperKEKB is an e⁻e⁺ collider, which is an upgraded accelerator of KEKB with the aim to increase the luminosity by more than one order. The superconducting cavities are used in the electron ring. The superconducting cavities were designed as a HOM-damped structure for KEKB and were operated up to 1.4 A in KEKB. However, the design storage current of the electron ring for SuperKEKB is 2.6 A, which is about twice the achievement current of KEKB. The HOM power is estimated to increase from 16 kW, which is the performance value in KEKB, to over 35 kW. This large load is unacceptable for the ferrite HOM dampers mounted on both sides of the cavity. As a countermeasure, duct type SiC HOM dampers are inserted between the cavities. The HOM damper load tests were performed during normal beam operation with a maximum current of 1.1 A. The load on the downstream ferrite HOM damper decreased due to the HOM power absorbed by the upstream SiC damper. In addition, the load was found to be dependent on the beam filling pattern. We will present the results and discussion of beam tests on the loading of HOM dampers and the dependence on the beam filling pattern in SuperKEKB.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 271
EP  - 274
KW  - HOM
KW  - cavity
KW  - SRF
KW  - superconducting-cavity
KW  - operation
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB068
UR  - https://jacow.org/srf2023/papers/mopmb068.pdf
ER  - 

TY  - CONF
AU  - Kramer, F.
AU  - Keckert, S.
AU  - Knobloch, J.
AU  - Kubo, T.
AU  - Kugeler, O.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Study of the Dynamics of Flux Trapping in Different SRF Materials
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - A dedicated experimental setup to measure magnetic flux dynamics and trapped flux in samples is used to precisely map out how trapped flux is influenced by different parameters. The setup allows for rapid thermal cycling of the sample so that effects of cooldown parameters can be investigated in detail. We show how temperature gradient, cooldown rate, and the magnitude of external field influence trapped flux in large grain, fine grain and coated niobium samples. The detailed measurements show unexpected results, namely that too fast cooldowns increase trapped flux, large grain material traps flux only when the external field is larger than a temperature gradient dependent threshold field, and the measured dependence of trapped flux on temperature gradient does not agree with an existing model. Therefore, a new model is presented which agrees better with the measured results.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 380
EP  - 387
KW  - experiment
KW  - cavity
KW  - ECR
KW  - niobium
KW  - controls
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUCXA01
UR  - https://jacow.org/srf2023/papers/tucxa01.pdf
ER  - 

TY  - CONF
AU  - Kramer, F.
AU  - Keckert, S.
AU  - Knobloch, J.
AU  - Kubo, T.
AU  - Kugeler, O.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Modelling Trapped Flux in Niobium
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Detailed measurements of magnetic flux dynamics and trapped magnetic flux in niobium samples were conducted with a new experimental setup that permits precise control of the cooldown parameters. With this setup the dependency of trapped flux on the temperature gradient, external magnetic field, and cooldown rate can be mapped out in more detail compared to cavity measurements. We have obtained unexpected results, and an existing model describing trapped flux in dependence of temperature gradient does not agree with the measured data. Therefore, a new model is developed which describes the magnitude of trapped flux in dependence of the temperature gradient across the sample during cooldown. The model describes the amount of trapped flux lines with help of a density distribution function of the pinning forces of pinning centers and the thermal force which can de-pin flux lines from pinning centers. The model shows good agreement with the measured data and correctly predicts trapped flux at different external flux densities.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 393
EP  - 397
KW  - ECR
KW  - experiment
KW  - cavity
KW  - niobium
KW  - controls
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB002
UR  - https://jacow.org/srf2023/papers/tuptb002.pdf
ER  - 

TY  - CONF
AU  - Ito, H.
AU  - Sakai, H.
AU  - Takahashi, K.
AU  - Umemori, K.
AU  - Yamada, T.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Development of Nb₃Sn Coating System and RF Measurement Results at KEK
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - We have constructed an Nb₃Sn cavity coating system based on the Sn vapor diffusion method. After the construction, improvement of our coating system and environment has been conducted through sample and cavity coating research. Our cavity achieves a Q-value above 1E10 at 4 K after improvement. We will report on the detail of improvement on our coating system and RF measurement results of single-cell Nb₃Sn cavity.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 414
EP  - 418
KW  - cavity
KW  - SRF
KW  - radio-frequency
KW  - accelerating-gradient
KW  - controls
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB014
UR  - https://jacow.org/srf2023/papers/tuptb014.pdf
ER  - 

TY  - CONF
AU  - Tajima, T.
AU  - Grumstrup, T.P.
AU  - Ito, H.
AU  - Kako, E.
AU  - Okada, T.
AU  - Sakai, H.
AU  - Thompson, J.D.
AU  - Umemori, K.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - MgB₂ Coating Parameter Optimization Using a 1.3-GHz 1-Cell Cavity
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 425
EP  - 428
KW  - cavity
KW  - SRF
KW  - controls
KW  - experiment
KW  - vacuum
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB018
UR  - https://jacow.org/srf2023/papers/tuptb018.pdf
ER  - 

TY  - CONF
AU  - Chambrillon, J.K.
AU  - Bazin, N.
AU  - Cara, P.
AU  - Carin, Y.
AU  - Chauvin, N.
AU  - Duglue, G.
AU  - Dzitko, H.
AU  - Ebisawa, T.
AU  - Gex, D.
AU  - Hasegawa, K.
AU  - Jimenez-Rey, D.
AU  - Kako, E.
AU  - Kondo, K.
AU  - Masuda, K.
AU  - Mollá, J.
AU  - Möller, W.-D.
AU  - Phillips, G.
AU  - Podadera, I.
AU  - Sakai, H.
AU  - Scantamburlo, F.
AU  - Sugimoto, M.
AU  - Yanagimachi, T.Y.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Cleanroom Assembly of the LIPAc Cryomodule
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 452
EP  - 457
KW  - solenoid
KW  - SRF
KW  - cavity
KW  - cryomodule
KW  - pick-up
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB027
UR  - https://jacow.org/srf2023/papers/tuptb027.pdf
ER  - 

TY  - CONF
AU  - Sakai, H.
AU  - Kako, E.
AU  - Katayama, R.
AU  - Umemori, K.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Measurement of Particulates under Slow Pumping after High Pressure Rinsing of Superconducting Cavity by Using Modified Slow Pumping System
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 458
EP  - 462
KW  - cavity
KW  - vacuum
KW  - controls
KW  - cryomodule
KW  - SRF
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB029
UR  - https://jacow.org/srf2023/papers/tuptb029.pdf
ER  - 

TY  - CONF
AU  - Yamamoto, Y.
AU  - Dohmae, T.
AU  - Hiraki, M.H.
AU  - Sakai, H.
AU  - Umemori, K.
AU  - Yamada, T.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Development of Automatic Cleaning and Assembly Systems in Clean Room at KEK
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - At KEK, new clean work systems including vertical auto cleaning system, replacement system between blank flange and bellows, and robot arm have been developed and installed since 2020 under the collaboration between Japan and France. The main purpose is unmanned and dust-free operation in clean room to avoid performance degradation with field emission in vertical test and cryomodule test. The vertical auto cleaning system and the replacement system between blank flange and bellows have been operated successfully in 2021-2022. Currently, clean work studies related to auto cleaning and assembly is under progress by combining the blank-bellows replacement system and a robot arm. In this report, the recent status of clean works at KEK will be presented.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 463
EP  - 466
KW  - cavity
KW  - gun
KW  - operation
KW  - monitoring
KW  - controls
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB030
UR  - https://jacow.org/srf2023/papers/tuptb030.pdf
ER  - 

TY  - CONF
AU  - Ebisawa, T.
AU  - Carin, Y.
AU  - Chambrillon, J.K.
AU  - Chauvin, N.
AU  - Dzitko, H.
AU  - Gex, D.
AU  - Hasegawa, K.
AU  - Kako, E.
AU  - Kasugai, A.
AU  - Kondo, K.
AU  - Masuda, K.
AU  - Phillips, G.
AU  - Sakai, H.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Operational Consideration in the LIPAc SRF with Potential Solenoid Failure Modes
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 467
EP  - 470
KW  - solenoid
KW  - SRF
KW  - simulation
KW  - operation
KW  - cryomodule
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB031
UR  - https://jacow.org/srf2023/papers/tuptb031.pdf
ER  - 

TY  - CONF
AU  - Konomi, T.
AU  - Hara, K.
AU  - Honda, Y.
AU  - Hosoyama, K.
AU  - Inoue, H.
AU  - Kako, E.
AU  - Kondo, Y.
AU  - Masuzawa, M.
AU  - Omet, M.
AU  - Takatomi, T.
AU  - Terashima, A.
AU  - Tsuchiya, K.
AU  - Ueki, R.
AU  - Umemori, K.
AU  - Wang, X.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Horizontal Test Results of 1.3 GHz Superconducting RF Gun #2 at KEK
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 540
EP  - 544
KW  - gun
KW  - cavity
KW  - cathode
KW  - SRF
KW  - laser
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB049
UR  - https://jacow.org/srf2023/papers/tuptb049.pdf
ER  - 

TY  - CONF
AU  - Yamanaka, M.
AU  - Shimada, K.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - A Novel Manufacture of Niobium SRF Cavities by Cold Spray
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Cold spray is a lower-temperature solid-state thermal spray process that deposits metal powder using a heated inert gas through a supersonic nozzle. When the material hits at supersonic speed and reaches the critical speed, the particles themselves are plastically deformed to form a film. The material of the superconducting cavity is niobium, a very expensive rare metal. To reduce the amount of niobium and the cost, we propose a novel manufacturing method of forming a thick niobium film on the surface of a mandrel by cold spray using niobium powder and removing the mandrel to finish a hollow shape. We confirmed the feasibility of the proposed method using a model similar to a 3.9 GHz one-cell cavity. Also, the RRR measurement of the niobium specimen made by cold spray was carried out and the measured value of 11 was obtained. We report on these results.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 545
EP  - 548
KW  - cavity
KW  - SRF
KW  - niobium
KW  - radio-frequency
KW  - experiment
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB052
UR  - https://jacow.org/srf2023/papers/tuptb052.pdf
ER  - 

TY  - CONF
AU  - Yoon, J.Y.
AU  - Han, J.H.
AU  - Kako, E.
AU  - Kim, E.-S.
AU  - Park, H.S.
AU  - Yoon, Y.D.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - RF Measurements of the 3rd Harmonic Superconducting Cavity for a Bunch Lengthening
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 565
EP  - 567
KW  - cavity
KW  - niobium
KW  - target
KW  - superconducting-cavity
KW  - MMI
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB062
UR  - https://jacow.org/srf2023/papers/tuptb062.pdf
ER  - 

TY  - CONF
AU  - Kumar, A.
AU  - Araki, H.
AU  - Dohmae, T.
AU  - Ito, H.
AU  - Saeki, T.
AU  - Umemori, K.
AU  - Yamamoto, A.
AU  - Yamanaka, M.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Development of the Directly-Sliced Niobium Material for High Performance SRF Cavities
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - For the purpose of cost reduction for the ILC, KEK has been conducting R&D on direct sliced Nb materials such as large grain and medium grain Nb. Single-cell, 3-cell, and 9-cell cavities have been manufactured, and each has demonstrated a high-performance accelerating gradient exceeding 35 MV/m. The results of applying high-Q/high-G recipes, such as two-step baking and furnace baking to these cavities are also shown. Moreover, mechanical tests have been carried out for the beforementioned materials to evaluate their strength for application to the High-Pressure Gas Safety Law. The status of development of these large grain and Medium grain Nb will be presented.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 634
EP  - 640
KW  - cavity
KW  - SRF
KW  - niobium
KW  - collider
KW  - linear-collider
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-WEIXA04
UR  - https://jacow.org/srf2023/papers/weixa04.pdf
ER  - 

TY  - CONF
AU  - Hryhorenko, O.
AU  - Antoine, C.Z.
AU  - Dohmae, T.
AU  - Keckert, S.
AU  - Knobloch, J.
AU  - Kugeler, O.
AU  - Longuevergne, D.
AU  - Proslier, Th.
AU  - Éozénou, F.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Recent Advances in Metallographic Polishing for SRF Application
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - This talk is an overview of the metallographic polishing R&D program covering Niobium and Copper substrates treatment for thin film coating as an alternative fabrication pathway for 1.3 GHz elliptical cavities. The presented research is the result of a collaborative effort between IJCLab, CEA/Irfu, HZB, and KEK in order to develop innovative surface processing and cavity fabrication protocols capable of meeting stringent requirements for SRF surfaces, including the reduction of safety risks and ecological footprint, enhancing reliability, improving the surface roughness, and potentially allowing cost reduction. The research findings will be disclosed.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 646
EP  - 650
KW  - cavity
KW  - SRF
KW  - niobium
KW  - laser
KW  - framework
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-WEIXA06
UR  - https://jacow.org/srf2023/papers/weixa06.pdf
ER  - 

TY  - CONF
AU  - Hryhorenko, O.
AU  - Antoine, C.Z.
AU  - Dohmae, T.
AU  - Longuevergne, D.
AU  - Valizadeh, R.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Exploring Innovative Pathway for SRF Cavity Fabrication
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - This article shows a study on an alternative pathway for the fabrication of a complete 1.3 GHz SRF cavity, aiming at improving production reliability, reducing the use of chemical polishing (EP or BCP) which is a costly and safety-critical step, and preserving surface quality after forming. Unlike the conventional pathway, the fabrication process is performed after polishing. This point is crucial as the used polishing technology could be applied only to flat geometries. The performed investigation demonstrates that damages during the fabrication process are considered minor, localized, and limited to the near-surface. Moreover, these studies confirm that the damaged layer (100-200 µm) is mainly caused by the rolling process, and not by the subsequent fabrication steps. A laser confocal microscope and SEM-EBSD technique were used to compare samples before and after forming. The preliminary results are discussed and presented in this paper.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 680
EP  - 684
KW  - cavity
KW  - SRF
KW  - niobium
KW  - laser
KW  - electron
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-WEPWB050
UR  - https://jacow.org/srf2023/papers/wepwb050.pdf
ER  - 

TY  - CONF
AU  - Ebisawa, T.
AU  - Hasegawa, K.
AU  - Kako, E.
AU  - Kasugai, A.
AU  - Oyaidzu, M.
AU  - Sakai, H.
AU  - Sato, S.
AU  - Umemori, K.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Basic Design and Consideration of Li-Vapor Contamination for A-FNS SRF
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 773
EP  - 777
KW  - SRF
KW  - cavity
KW  - solenoid
KW  - linac
KW  - operation
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-WEPWB083
UR  - https://jacow.org/srf2023/papers/wepwb083.pdf
ER  - 

TY  - CONF
AU  - Yamamoto, Y.
AU  - Matsumoto, T.
AU  - Michizono, S.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Development and Evaluation of STF-Type Power Coupler for Cost Reduction at the High Energy Accelerator Research Organization
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - At KEK, cost reduction study for STF-type input power coupler used in the STF-2 accelerator has been attempted since FY2015. In FY2019, one coupler was fabricated by some cost-effective and non-conventional methods including different alumina-ceramic material, copper plating and TiN coating. In high power RF test at room temperature, this coupler achieved 1 MW at 900 µsec/5Hz, and 935 kW @1.65 msec/5Hz. After that, this coupler experienced 10 thermal cycle tests from room temperature to liquid nitrogen temperature without vacuum leakage. In this report, the detailed results will be presented.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 820
EP  - 822
KW  - vacuum
KW  - SRF
KW  - GUI
KW  - cryomodule
KW  - cavity
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-WEPWB098
UR  - https://jacow.org/srf2023/papers/wepwb098.pdf
ER  - 

TY  - CONF
AU  - Yamanaka, M.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - A Novel Twin Drive Tuner Mechanism for 1.3 GHz ILC Cavity
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - A tuner is a device that adjusts the resonant frequency of a cavity. Here we propose a new tuner mechanism for the 1.3 GHz ILC cavity. A bellow is provided in the central portion of the helium tank in the longitudinal direction, and flanges are provided on both sides of the bellows. A linear motion actuator is fixed to the flange on one side, and the frequency is changed by pushing and pulling the flange on the opposite side. Significantly, two linear motion actuators are placed in circumference and working simultaneously. It is named a twin-drive tuner. According to the ILC specification, the cavity has a spring constant of 3 KN/mm, requiring a stroke of 2 mm to adjust the 600 kHz range. A loading force of 6 kN is required. This is shared by two linear motion actuators. We developed a prototype actuator with a loading force of 4 kN per unit. It consists of a stepping motor and a sliding screw with a plastic nut. An experimental device was constructed using this actuator and a 1.3 GHz cavity with a helium tank, and the frequency tuning was evaluated. The displacement between the flanges and the frequency are proportional, both have good linearity, and the slope is 296 kHz/mm.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 914
EP  - 916
KW  - cavity
KW  - SRF
KW  - FEL
KW  - operation
KW  - site
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-WEPWB135
UR  - https://jacow.org/srf2023/papers/wepwb135.pdf
ER  - 

TY  - CONF
AU  - Kondo, Y.
AU  - Dohmae, T.
AU  - Kako, E.
AU  - Maekawa, F.
AU  - Meigo, S.I.
AU  - Sakai, H.
AU  - Tamura, J.
AU  - Umemori, K.
AU  - Yee-Rendón, B.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Development of Single-spoke Cavities for  ADS at JAEA
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 947
EP  - 951
KW  - cavity
KW  - linac
KW  - SRF
KW  - emittance
KW  - proton
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-THCAA01
UR  - https://jacow.org/srf2023/papers/thcaa01.pdf
ER  - 

TY  - CONF
AU  - McIntosh, P.A.
AU  - Belomestnykh, S.A.
AU  - Burt, G.
AU  - Calaga, R.
AU  - De Silva, S.U.
AU  - Delayen, J.R.
AU  - Gonin, I.V.
AU  - Khabiboulline, T.N.
AU  - Lunin, A.
AU  - Okugi, T.
AU  - Orlov, Y.M.
AU  - Verdú-Andrés, S.
AU  - Xiao, B.P.
AU  - Yakovlev, V.P.
AU  - Yamamoto, A.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Crab Cavities for ILC
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - For the 14 mrad crossing angle proposed, crab cavity systems are fundamentally anticipated for the viable operation of the International Linear Collider (ILC), in order to maximise its luminosity performance. Since 2021, a specialist development team have been defining optimum crab cavity technologies which can fulfil the operational requirements for ILC, both for its baseline centre-of-mass energy of 250 GeV, but also extending those requirements out to higher beam collision intensities. Five design teams have established crab cavity technology solutions, which have the capability to also operate up to 1 TeV centre-of-mass. This presentation showcases the key performance capabilities of these designs and their associated benefits for both manufacture and integration into the ILC Interaction Region. The recommended outcome of the recently conducted crab cavity technology down-selection, will also be highlighted.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 990
EP  - 998
KW  - cavity
KW  - HOM
KW  - SRF
KW  - operation
KW  - impedance
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-FRIBA04
UR  - https://jacow.org/srf2023/papers/friba04.pdf
ER  -