Thermal analysis on voltage responses of high-Tc superconducting thin-films exposed to a pulse laser beam

Abstract

One-dimensional radiation/conduction heat transfer model is employed to investigate thermal responses of HTSC thin-film detectors exposed to a pulse laser beam. The theoretical model includes local radiation absorption in the HTSC film based on the electromagnetic theory, thermal contact resistances at the interface between film and substrate, and nonuniform initial condition for the film/substrate temperature incurred by the Joule heating due to the bias current and inherent electrical resistance even before the radiation exposure. Using the steady-state conduction equation, the experimental resistance-temperature curve is corrected based on the real film temperatures instead of the substrate temperatures. The error involved in the estimation of the voltage jump based on the model without initial Joule heating could be significant near the transition temperature. Still there is a big discrepancy between the theoretical and experimental results, though the nonuniform initial condition model reduces the gap.