Near-adiabatic quench experiments on short YBa2Cu3O7− coated conductors

Minimum quench energy and normal zone propagation velocity are measured on short YBa2Cu3O7− coated conductors in self-field at temperatures ranging from 40 to 77 K. The sample is cooled via a cryocooler with a cryostat pressure of 10−4 Pa, creating a nearly adiabatic environment. A normal zone is created by pulsing a heater that is attached to the sample surface with a thin layer of alumina-filled epoxy. The minimum quench energy is determined by identifying the minimum heater energy that creates a propagating normal zone, and the propagation velocity is determined from the time delay between voltage signals in voltage taps distributed along the length of the conductor. It is found that the minimum quench energy is on the order of 1 J and the normal zone propagation velocity ranges from 1–40 mm/s. These results are compared to similar measurements on other coated conductor architectures and geometries and to the classical adiabatic quench propagation model. © 2007 American Institute of Physics. DOI: 10.1063/1.2435804