Thermal Coupling Effect on the AC Thermal Signal and DC Characteristics of High-Temperature Superconducting Bolometers

概要

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In a high-temperature superconducting (HTSC) bolometer, the irradiated thermal energy is absorbed by the film and finally drained to the heat sink. The intensity of the thermal signal depends on the level of the AC irradiation energy accumulated. It is usually expected that the magnitude of AC thermal signal is enhanced by weakening the thermal coupling of the bolometer to the heat sink. However, in this study, we found that the AC thermal signal, $\Delta T/W_{\text{D}}$, was not enhanced but was depressed by weakening the thermal coupling of the setup. This could be attributed to the nature of the low dissipation ability in the weak thermal coupling configuration which accumulated a higher level of DC Joule heat and gave rise to a huge temperature gradient between the film and the heat sink. As a result, the heat dissipation was sped up and the AC thermal signal, $\Delta T/W_{\text{D}}$, was depressed. Even though the AC thermal signal was lower in the weak thermal coupling configuration than in the strong one, the optimum operation condition, where maximum $\Delta T/W_{\text{D}}$ was exhibited, was located in the lower bias current region. This has the advantage of enabling the weak thermal coupling configuration to be operated in a lower-power consumption region.
Publication Office, Japanese Journal of Applied Physics, Faculty of Science, University of Tokyoの論文
2001-02-15