Nunez von Voigt, P.; Knobloch, J.; Kugeler, O.: Investigation of Trapped Flux Dynamics via DC-Magnetic Quenching. In: Peter Michel ... [Ed.] : SRF2019, Proceedings of the 19th International Conference on RF Superconductivity, Dresden, GermanyGeneve: JACoW, 2019. - ISBN 978-3-95450-211-0, p. 580-582
http://jacow.org/srf2019/papers/tup059.pdf
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Abstract:
Trapped magnetic flux increases the surface resistance in superconducting radio-frequency cavities. A better understanding of its behaviour could help to develop a method of expelling trapped flux from the superconducting surface. Using a superconducting coil with ferrite core attached to a 3 GHz sample Niobium cavity fully immersed in liquid Helium, we were able to subject the cavity walls to unusually large magnetic fields (estimated > 150 mT) and create magnetic quenches. With Fluxgate sensors attached in three spatial directions inside the cavity, we were able to monitor the quench dynamics and extract parameters of the flux dynamics from the hysteretic behaviour of the measured fields resulting from the applied coil current. First results of manipulation of the trapped flux with high magnetic fields are presented.