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TY - CONF AU - Vandoni, G. AU - Furci, H. AU - Koettig, T. AU - Macpherson, A. AU - Turaj, K. AU - Vega Cid, L. ED - Michel, Peter ED - Arnold, André ED - Schaa, Volker RW TI - Thermal Mapping of SRF Cavities by Second Sound Detection With Transition Edge Sensors and Oscillating Superleak Transducers J2 - Proc. of SRF2019, Dresden, Germany, 30 June-05 July 2019 CY - Dresden, Germany T2 - International Conference on RF Superconductivity T3 - 19 LA - english AB - The SRF cavity testing facilities at CERN include four vertical cryostat stations in SM18 and a cryostat for small cavities in the Cryolab. A large range of structures are tested, from Nb thin film cavities for HIE-Isolde and LHC, to bulk Nb crab cavities for HiLumi or 704 MHz 5-cell high-gradient cavities. To cope with different shapes and small series tests, thermal mapping diagnostics is deployed by sensing second sound in superfluid helium. A new type of Transition Edge Sensors (TES) has been developed in the last 2 years. These are miniature resistors of thin-film superconducting alloys, micro-produced on insulating wafers. An extensive campaign of optimization of design, fabrication process and composition was accompanied by qualification in a calibration cryostat. Reproducibility, stability, then intensity, distance and angular dependence of the response were assessed and compared to Oscillating Superleak Transducers (OST). The TES were then installed in a vertical cryostat for tests of a prototype crab cavity for HiLumi. TES are now applied to quench localization on high gradient cavities, for which the most recent results will be presented, together with the OST results. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1182 EP - 1186 KW - cavity KW - SRF KW - diagnostics KW - experiment KW - luminosity DA - 2019/08 PY - 2019 SN - "" SN - 978-3-95450-211-0 DO - doi:10.18429/JACoW-SRF2019-THP105 UR - http://jacow.org/srf2019/papers/thp105.pdf ER -