Study on Mutual-Inductance-Based Quench Detector Dedicated to Corrector Magnets of SIS100

SIS100-the primary particle accelerator of the FAIR project, utilizes special corrector magnets, which coils are wound with a Nuclotrontype cable with insulated superconducting wires. The wires are connected in series and in this way, the nominal current of the coil can be limited to 200-300 Amperes. Consequently, the current leads and the room temperature power distribution line can be designed with low cross sections. Unfortunately, such a coil design is sensitive to symmetrical quenches as, e.g., induced by beam losses that cannot be detected by a typical balance bridge detector. Therefore, it was decided to work on another quench detection method that considers voltage measurement at the pickup coil directly coupled with the magnet coil. Such a detector is called mutual-inductance-based detector (MID). Two prototypes were built in the last years in order to prove the measurement concept and its reliability. The concept of MID and the design principle of the latest detector prototype followed by an evaluation study that included functionality tests are presented within this paper. The prototype was subjected to tests with superconducting solenoid manufactured with the SIS100 corrector cable. Selected measurement results followed by a detailed explanation of the acquired signals are reported.