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 - Asaduzzaman, M. AU - Junginger, T. AU - Laxdal, R.E. AU - McFadden, R.M.L. AU - Thoeng, E. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Muon Spin Rotation Studies of Bilayer Superconductors and Low Temperature Baked 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 - Muon spin rotation (muSR) results have shown that vortex penetration into Nb can be delayed up to the superheating field Hsh by a single layer of a material with larger London penetration depth. For low temperature baked (LTB) Nb an increase in the vortex penetration field Hvp has also been observed. While clearly exceeding the lower critical field Hc1, Hvp was found to remain significantly below Hsh for LTB niobium (Superconductor Science and Technology 30 (12), 125012). Further, magnetometry experiments suggested that there is no interface barrier in LTB Nb and that the apparent Hvp increase as observed by muSR was due to surface pinning (Scientific Reports 12 (1), 5522). By varying the implantation depth of ~4.1 MeV muons using moderating foils, new muSR measurements confirm that the apparent Hvp increase in LTB Nb is indeed due to surface pinning, while for a Nb₃Sn/Nb bilayer we find an interface barrier for flux penetration. These results confirm the potential of using superconducting bilayers to achieve a flux free Meissner state up to the superheating field of the substrate. PB - JACoW Publishing CP - Geneva, Switzerland SP - 62 EP - 66 KW - interface KW - experiment KW - cavity KW - polarization KW - niobium DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB005 UR - https://jacow.org/srf2023/papers/mopmb005.pdf ER - TY - CONF AU - Smith, L.G.P. AU - Burt, G. AU - Junginger, T. AU - Malyshev, O.B. AU - Turner, D.A. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Investigation, Using Nb Foils to Characterise the Optimal Dimensions of Samples Measured by the Magnetic Field Penetration Facility 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 - SRF cavities made of bulk Nb are reaching their theoretical limits in the maximum accelerating gradient, E_{acc}, where E_{acc} is limited by the maximum magnetic field, Bmax, that can be applied on the surface of the accelerating cavity wall. To increase E_{acc}, Bmax, which can be applied to the surface, must also be increased. The A15 materials or multilayer structures are the potential solution to increase Bmax. Since coating and RF testing of full size RF cavities is both expensive and time consuming, one need to evaluate new ideas in superconducting thin films quickly and at low cost. A magnetic field penetration experiment has been designed and built at Daresbury Laboratory to test small superconducting samples. The facility produces a parallel DC magnetic field, which applied from one side of the sample to the other similar to that in an RF cavity. The facility applies an increasing magnetic field at a set temperature to determine the field of full flux penetration which can give an insight into the quality and structure of the superconducting structure. The facility has been characterised using both type I and II superconductors and is now producing results from novel materials. PB - JACoW Publishing CP - Geneva, Switzerland SP - 88 EP - 91 KW - cavity KW - SRF KW - experiment KW - ECR KW - niobium DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB012 UR - https://jacow.org/srf2023/papers/mopmb012.pdf ER - TY - CONF AU - Gregory, R.R. AU - Junginger, T. AU - Kolb, P. AU - Laxdal, R.E. AU - McMullin, M.W. AU - Yao, Z.Y. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Magnetic Flux Expulsion in TRIUMF’s Multi-Mode Coaxial 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 - The external magnetic flux sensitivity of SRF cavities is an important characteristic of SRF accelerator design. Previous studies have shown that n-doped elliptical cavities are very sensitive to external fields, resulting in stringent requirements for residual field and cavity cool-down speed. Few such studies have been done on HWRs and QWRs. The impact of applied field direction and cool-down speed of flux expulsion for these cavities is poorly understood. This study explores the effect of these cool-down characteristics on TRIUMF¿s QWR using COMSOL ® simulations and experimental results. This study seeks to maximize the flux expulsion that occurs when a cavity is cooled down through its superconducting temperature. Flux expulsion is affected by the cool-down speed, temperature gradient, and orientation of the cavity relative to an applied magnetic field. It was found that for a vertically applied magnetic field the cool-down speed and temperature gradient did not have a significant effect on flux expulsion. Contrarily, a horizontal magnetic field can be nearly completely expelled by a fast, high temperature gradient cool-down. PB - JACoW Publishing CP - Geneva, Switzerland SP - 135 EP - 140 KW - cavity KW - simulation KW - SRF KW - experiment KW - controls DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB023 UR - https://jacow.org/srf2023/papers/mopmb023.pdf ER - TY - CONF AU - Kolb, P. AU - Al Hassini, H. AU - Fearn, L. AU - Junginger, T. AU - Keir, J.J. AU - Laxdal, R.E. AU - Matheson, B. AU - Yao, Z.Y. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Temperature Mapping for Coaxial Cavities at TRIUMF 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 - Temperature mapping (T-map) on superconducting radio-frequency (SRF) cavities has been shown as a useful tool to identify defects and other abnormal sources of losses. So far T-map systems have only been realized for elliptical cavities that have an easily accessible outer surface. TEM mode cavities such as quarterwave and halfwave resonators (QWR, HWR) dissipate most of their power on the inner conductor of the coaxial structure. The limited access and constrained space are a challenge for the design of a temperature mapping system. This paper describes the mechanical and electrical design including the data acquisition of a T-map system for the TRIUMF multi-mode coaxial cavities, and first results are shown. PB - JACoW Publishing CP - Geneva, Switzerland SP - 183 EP - 186 KW - cavity KW - SRF KW - LabView KW - data-acquisition KW - ECR DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB038 UR - https://jacow.org/srf2023/papers/mopmb038.pdf ER - TY - CONF AU - McMullin, M.W. AU - Junginger, T. AU - Kolb, P. AU - Laxdal, R.E. AU - Yao, Z.Y. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Thermal Feedback in Coaxial 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 - The phenomenon of Q-slope in SRF cavities is caused by a combination of thermal feedback and field-dependent surface resistance. There is currently no commonly accepted model of field-dependent surface resistance, and studies of Q-slope generally treat thermal feedback as a correction to whichever surface resistance model is being used. In the present study, we treat thermal feedback as a distinct physical effect whose effect on Q-slope is calculated using a novel finite-element code. We performed direct measurements of liquid helium pool boiling from niobium surfaces to obtain input parameters for the finite-element code. This code was used to analyze data from TRIUMF’s coaxial test cavity program, which has provided a rich dataset of Q-curves at temperatures between 1.7 K and 4.4 K at five different frequencies. Preliminary results show that thermal feedback makes only a small contribution to Q-slope at temperatures near 4.2 K, but has stronger effects as the bath temperature is lowered. PB - JACoW Publishing CP - Geneva, Switzerland SP - 224 EP - 229 KW - cavity KW - niobium KW - feedback KW - SRF KW - ECR DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB050 UR - https://jacow.org/srf2023/papers/mopmb050.pdf ER - TY - CONF AU - Yao, Z.Y. AU - Laxdal, R.E. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Performance of Contaminated Superconducting Linac after Vacuum Excursion 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 - ISAC-II superconducting heavy ion linac is the high energy section of TRIUMF ISAC facility to accelerate rare isotopes with A/q <= 6 from 1.5 MeV/u to above the Cou-lomb barrier for experiments. There was a vacuum excur-sion caused by an operational error and the failure of the fast protection system in summer 2022. The beamline downstream to the SC linac was vented with atmosphere air from the experimental hall resulting in pollution of the linac. This paper reports the RF performance of the con-taminated linac. The typical cavity performance changes, the average magnitude of degradation, the impact range in the SC linac, the observations in the recovery processes and the analyses on the most distinct cavity are discussed. The cavity refurbishment in the recent winter shutdown with the observations and outcomes is also reported. The ISAC-II event provided a unique data set for the SRF community. PB - JACoW Publishing CP - Geneva, Switzerland SP - 332 EP - 336 KW - cavity KW - cryomodule KW - vacuum KW - ISAC KW - linac DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB092 UR - https://jacow.org/srf2023/papers/mopmb092.pdf ER - TY - CONF AU - Thoeng, E. AU - Asaduzzaman, M. AU - Dunsiger, S.R. AU - Fujimoto, D. AU - Junginger, T. AU - Karner, V.L. AU - Kiefl, R. AU - Kolb, P. AU - Laxdal, R.E. AU - Li, R. AU - MacFarlane, W.A. AU - McFadden, R.M.L. AU - Morris, G. AU - Stachura, M. AU - Ticknor, J.O. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - First Results from beta-SRF- Testing SRF Samples at High Parallel Field 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 new ¿-SRF facility at TRIUMF has recently been commissioned. A new 1 m extension has been added to an existing ¿-NMR beamline with a large Helmholtz coil to produce fields up to 200 mT parallel to sample surfaces. The ¿-NMR technique allows depth dependent characterization of the local magnetic field in the first 100 nm of the sample surface making the probe ideal for studying Meissner screen- ing in heat treated Niobium or layered SRF materials. First measurements of Meissner screening at fields up to 200 mT have been analyzed. The results show clear differences in the Meissner screening of baseline treatments compared to mid-T baked (O-doped) Niobium. PB - JACoW Publishing CP - Geneva, Switzerland SP - 374 EP - 379 KW - SRF KW - polarization KW - experiment KW - niobium KW - ISAC DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-TUIXA04 UR - https://jacow.org/srf2023/papers/tuixa04.pdf ER - TY - CONF AU - Kalboussi, Y. AU - Antoine, C.Z. AU - Asaduzzaman, M. AU - Baudrier, M. AU - Bertrand, Q. AU - Boulch, C. AU - Delatte, B. AU - Dragoe, D. AU - Jullien, G. AU - Junginger, T. AU - Lochet, N. AU - Longuevergne, D. AU - Maurice, L. AU - Miserque, F. AU - Proslier, Th. AU - Pépin-Donat, T. AU - Sahuquet, P. AU - Vacher, T.V. AU - Éozénou, F. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Surface Engineering by ALD for Superconducting RF 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 - Atomic Layer Deposition is a synthesis method that enable a unique control of thin films chemical composition and thickness over complex shape objects such as SRF cavities. This level of control opens the way to new surface treatments and to study their effect on RF cavity performances. We will present coupon and, in some cases, preliminary cavity results, from various surface engineering routes based on the deposition of thin oxides and nitrides films combined with post annealing treatments and study their interactions with the niobium. Three main research directions will be presented: 1/ replacing the niobium oxides by other surface layers (Al₂O₃, Y2O3, MgO) and probe their effect on the low and high field performances, 2/ doping with N and combine approaches 1/ and 2/ and finally 3/ optimize the superconducting properties of NbTiN multilayers on Nb and Sapphire. PB - JACoW Publishing CP - Geneva, Switzerland SP - 615 EP - 620 KW - cavity KW - niobium KW - vacuum KW - SRF KW - site DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-WEIBA01 UR - https://jacow.org/srf2023/papers/weiba01.pdf ER -