TY - CONF AU - Turner, D.A. AU - Gallifa Terricabras, A. AU - González Díaz-Palacio, I. AU - Hillert, W. AU - Koettig, T. AU - Macpherson, A. AU - Rosaz, G.J. AU - Stapley, N. AU - Wenskat, M. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Flux Expulsion Lens: Concept and Measurements 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 magnetic flux expulsion lens (MFEL) has been designed and built at CERN. This device uses closed topology conduction cooling of samples to quantify magnetic flux expulsion of superconductors, and allows for systematic measurements of the cooling dynamics and the magnetic response during the superconducting transition. Measurements for bulk Nb, cold worked Nb, sputtered Nb on Cu, and SIS multilayer structures are given. Preliminary results for both sample characterization of expulsion dynamics, and observation of an enhanced flux expulsion in SIS samples are also reported. PB - JACoW Publishing CP - Geneva, Switzerland SP - 56 EP - 61 KW - FEL KW - cavity KW - niobium KW - site KW - SRF DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB003 UR - https://jacow.org/srf2023/papers/mopmb003.pdf ER - TY - CONF AU - Vega Cid, L. AU - Atieh, S. AU - Bellini, G. AU - Bianchi, A. AU - Ferreira, L.M.A. AU - Leith, S.B. AU - Pereira Carlos, C. AU - Rosaz, G.J. AU - Venturini Delsolaro, W. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Results of the R&D RF Testing Campaign of 1.3 GHz Nb/Cu 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 - In the context of the R&D program on Nb/Cu carried out at CERN, a total of 25 tests have been performed since 2021. This talk will present these results. Three different manufacturing techniques have been used to produce the copper substrates, in order to investigate which is the most suitable in terms of quality and economy of scale. On one hand, the focus has been on optimizing the surface resistance at 4.2K, as this will be the operating temperature of FCC. The results at this temperature are encouraging, showing repeatable and optimized RF performance. On the other hand, RF tests have been done at 1.85 K too aiming at deepening the knowledge of the mechanisms behind the Q slope. This is key to work on the mitigation of this phenomenon and ultimately to extend the application of this technology to high energy, high gradient accelerators. The influence of the thermal cycles has been thoroughly investigated. A systematic improvement has been observed of both the Q slope and the residual resistance with slow thermal cycles. PB - JACoW Publishing CP - Geneva, Switzerland SP - 621 EP - 626 KW - cavity KW - SRF KW - niobium KW - operation KW - cryogenics DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-WEIXA02 UR - https://jacow.org/srf2023/papers/weixa02.pdf ER - TY - CONF AU - Gallifa Terricabras, A. AU - Aviles Santillana, I. AU - Barrière, S. AU - Cano-Pleite, E. AU - Garlasché, M. AU - Narduzzi, M. AU - Pfeiffer, S. AU - Prever-Loiri, L. AU - Swieszek, J.S. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Optimizing the Manufacture of High-Purity Niobium SRF Cavities Using the Forming Limit Diagram: A Case Study of the HL-LHC Crab Cavities RFD Pole 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 Crab Cavities are key components of the High Luminosity Large Hadron Collider (HL-LHC) project at CERN, which aims to increase the integrated luminosity of the LHC, the world’s largest particle accelerator, by a factor of ten. This paper explores the application of the Forming Limit Diagram (FLD) to enhance the manufacturing process of complex-shape Nb-based cavities, with a focus on the formability challenges experienced with the pole of the Radio Frequency Dipole (RFD) Crab Cavities. The study includes the material characterization of ultra-high-purity niobium (Nb RRR300) sheets, namely mechanical tests and microstructural analysis; it also contains large-deformation Finite Element simulations of the pole deep drawing process, and the translation of the resulting strains in a FLD diagram, together with several suggestions on how to improve the manufacturing process of such deep drawn parts. The results of this study can provide valuable insights into improving the design and fabrication of complex-shaped superconducting radio-frequency cavities made by large-deformation metal-sheet forming processes. PB - JACoW Publishing CP - Geneva, Switzerland SP - 627 EP - 633 KW - cavity KW - simulation KW - niobium KW - SRF KW - luminosity DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-WEIXA03 UR - https://jacow.org/srf2023/papers/weixa03.pdf ER -