Echevarria, P.; Knobloch, J.; Neumann, A.; Ushakov, A.; Aldekoa, E.; Jugo, J.: SRF Cavity Simulator For LLRF Algorithms Debugging. In: Shane Koscielniak ... [Ed.] : IPAC2018 : Proceedings of the 9th International Particle Accelerator Conference, Vancouver, Canada, April 29–May 4, 2018Geneve: JaCoW, 2018. - ISBN 978-3-95450-184-7, p. WEPAK013/1-3
http://ipac2018.vrws.de/papers/wepak013.pdf
Open Access Version
Abstract:
The availability of niobium superconducting cavities, either due to a lack of a real cavity or due to the time needed for the experiment set up (vacuum, cryogenics, cabling, etc.), is limited, and thus it can block or delay the development of new algorithms such as low level RF control. Hardware-in-the-loop simulations, where an actual cavity is replaced by an electronics system, can help to solve this issue. In this paper we present a Cavity Simulator implemented in a National Instruments PXI equipped with an FPGA module. This module operates with one intermediate frequency input which is IQ-demodulated and fed to the electrical cavity’s model, where the transmitted and reflected voltages are calculated and IQ-modulated to generate two intermediate frequency outputs. Some more advanced features such as mechanical vibration modes driven by Lorentz-force detuning or external microphonics have also been implemented. This Cavity Simulator is planned to be connected to an mTCA chassis to close the loop with a LLRF control system.