A Criterion of the Strain-Based Quench Decision for a Low-Temperature Superconducting Solenoid

It is important to pursue an efficacious way of detecting the quench in superconducting magnets as soon as possible so that the large magnetic energy stored in the magnets can be discharged duly. By means of strain measurement during the spontaneous quench, we recently proposed a quench-detection method for low-temperature superconducting solenoid magnets. By examining the leap character of strain-rate recorded, we further extended the strain-based quench-detection method. An appropriate criterion for the spontaneous quench was suggested and utilized for two liquid helium-cooled superconducting solenoids with different sizes and coil configurations. It was shown that the proposed method is capable of providing a safe criterion for the quench detection/protection within a short period of time, and it is a simple process comparing with the rate of quench development. The experimental data from the two different solenoids under excitation and quench tests supported the new strain-based detection method.