TY - CONF AU - Cierpka, A. AU - Keckert, S. AU - Knobloch, J. AU - Kramer, F. AU - Kugeler, O. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Analysis of Semiconductor Components as Temperature Sensors for Cryogenic Investigation of 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 - Temperature mapping systems have been used for many years to detect local heating in an SRF cavity surface or materials sample. They require a large number of temperature sensors. Most often, low-cost Allen-Bradley resistors are used for this purpose. Since they have poor sensitivity and reproducibility above 4 K, sensor alternatives that combine the precision of Cernox sensors with the low-cost of Allen-Bradley resistors would be highly desirable. In this work various semiconductor components that exhibit a temperature dependent electrical response, such as diodes and LEDs were analyzed with respect to sensitivity, reproducibility and response speed in a temperature range between 6.5 K and 22 K. In this range, many diodes and LEDs were found to be more sensitive than Cernox sensors. However, in some components the response time was slow - possibly due to poor thermal contact. PB - JACoW Publishing CP - Geneva, Switzerland SP - 80 EP - 83 KW - cavity KW - controls KW - cryogenics KW - experiment KW - SRF DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB010 UR - https://jacow.org/srf2023/papers/mopmb010.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 - Keckert, S. AU - Knobloch, J. AU - Kramer, F. AU - Kugeler, O. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Commissioning of a New Sample Test Cavity for Rapid RF Characterization of 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 - RaSTA, the Rapid Superconductor Test Apparatus, is a new sample test cavity that is currently being commissioned at HZB. It uses the established QPR sample geometry but with a much smaller cylindrical cavity operating in the TM020 mode at 4.8 GHz. Its compact design allows for smaller cryogenic test stands and reduced turnaround time, enabling iterative measurement campaigns for thin film R&D. Using the same calorimetric measurement technique as known from the QPR allows direct measurements of the residual resistance. We report first prototype results obtained from a niobium sample that demonstrate the capabilities of the system. PB - JACoW Publishing CP - Geneva, Switzerland SP - 410 EP - 413 KW - cavity KW - niobium KW - MMI KW - SRF KW - operation DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-TUPTB013 UR - https://jacow.org/srf2023/papers/tuptb013.pdf ER - TY - CONF AU - Pira, C. AU - Antoine, C.Z. AU - Azzolini, O. AU - Benjamin, C. AU - Berry, S. AU - Berton, R. AU - Bertucci, M. AU - Bonesso, M. AU - Bradley, J.W. AU - Burt, G. AU - Caforio, R. AU - Candela, S. AU - Candela, V. AU - Chyhyrynets, E. AU - Dima, R. AU - Favero, G. AU - Fonnesu, D. AU - Ford, D. AU - Garcia, V.A. AU - Hryhorenko, O. AU - Jiang, X. AU - Kalboussi, Y. AU - Keckert, S. AU - Keppel, G. AU - Knobloch, J. AU - Kugeler, O. AU - Leicester, N.L. AU - Longuevergne, D. AU - Malyshev, O.B. AU - Marconato, G. AU - Marks, N. AU - Medvids, A. AU - Mychko, A. AU - Onufrijevs, P. AU - Paparella, R. AU - Pepato, A. AU - Piccoli, D. AU - Piccoli, F. AU - Proslier, Th. AU - Prucnal, S. AU - Rebesan, P. AU - Ries, R. AU - Romanato, M. AU - Salmaso, A. AU - Seal, D.J. AU - Seiler, E. AU - Sian, B.S. AU - Simon, S. AU - Smith, L.G.P. AU - Squizzato, G. AU - Staedler, T. AU - Stivanello, F. AU - Telatin, F. AU - Turner, D.A. AU - Valente-Feliciano, A-M. AU - Valizadeh, R. AU - Zhou, S. AU - Zubtsovskii, A.O. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Progress in European Thin Film Activities 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 - Thin-film cavities with higher Tc superconductors (SC) than Nb promise to move the operating temperature from 2 to 4.5 K with savings 3 orders of magnitude in cryogenic power consumption. Several European labs are coordinating their efforts to obtain a first 1.3 GHz cavity prototype through the I.FAST collaboration and other informal collaborations with CERN and DESY. R&D covers the entire production chain. In particular, new production techniques of seamless Copper and Niobium elliptical cavities via additive manufacturing are studied and evaluated. New acid-free polishing techniques to reduce surface roughness in a more sustainable way such as plasma electropolishing and metallographic polishing have been tested. Optimization of coating parameters of higher Tc SC than Nb (Nb₃Sn, V₃Si, NbTiN) via PVD and multilayer via ALD are on the way. Finally, rapid heat treatments such as Flash Lamp Annealing and Laser Annealing are used to avoid or reduce Cu diffusion in the SC film. The development and characterization of SC coatings is done on planar samples, 6 GHz cavities, choke cavities, QPR and 1.3 GHz cavities. This work presents the progress status of these coordinated efforts. PB - JACoW Publishing CP - Geneva, Switzerland SP - 607 EP - 614 KW - cavity KW - SRF KW - target KW - niobium KW - laser DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-WECAA01 UR - https://jacow.org/srf2023/papers/wecaa01.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 -