Simulation of quench detection algorithms for Helmholtz Zentrum Berlin SRF cavities

The Helmholtz Zentrum Berlin is carrying out two accelerator projects which make use of high gradient Continuous Wave (CW) Superconducting Radiofrequency (SRF) cavities: bERLinPro and BESSY-VSR. In both projects, a prompt detection of a quench is crucial to avoid damages in the cryomodules and cavities themselves. In this paper, the response of real time estimation of the cavity parameters using the transmitted and forward RF signals is simulated, in order to perform the quench detection. The time response of the estimated half bandwidth is compared with the dissipated energy in the cavity walls for the different type of SRF cavities used in both projects, i.e., bERLinPro's photoinjector, booster and linac, and BESSY-VSR 1.5 GHz and 1.75 GHz cavities. As an intermediate step prior to the implementation in an mTCA.4 system together with the LLRF control and test with a real cavity, the algorithm has been implemented using a National Instruments FPGA board to check its proper behavior.