Study of UNK quench protection system on the string of 4 UNK superconducting magnets

The prototypes of the elements of UNK quench protection system-quench detectors on magnetic modulators, quench stopper, safety leads, bypass switches-are studied on the string of 4 UNK superconducting magnets. The string simulates the operation of two quench protection units (QPU). Many quenches at the various parts of SC circuit from 1 kA up to UNK nominal current 5 kA were induced. No quench propagation from one to another QPU was observed. Parameters of quench protection system elements corresponded to tolerated ones.