Authors
Zhang, J.; Chang, C.; Fujikawa, B.; Karapetrov, G.; Kolomensky, Yu.; Kwok, W.-K.; Lisovenko, M.; Novosad, V.; Pearson, J. ; Singh, V.; Wang, G.; Welliver, B.; Welp, U.; Yefremenko, V. G.
Abstract
We are developing a low-T-c TES-based large-area and low-threshold detector targeting a variety of potential applications. The detector consists of a 50.8-mm-diameter Si wafer as the substrate and radiation absorber, a single Ir/Pt bilayer TES sensor in the center, and normal metal Au pads added to the TES to strengthen the TES-absorber thermal coupling. Tight TES-absorber thermal coupling improves detector sensitivity and response uniformity. Here, we report on the electron-phonon (e-ph) coupling strengths for the Ir/Pt bilayer and Au that are measured with our prototype detectors and TES devices. We found that a second weak thermal link besides the one due to e-ph coupling in Ir/Pt or Au was required to explain our data. With the effects of the second weak link accounted for, the extracted e-ph coupling constant Sigma for Ir/Pt bilayer in the T-c range between 32 and 70 mK is 1.9 x 10(8) WK-5 m(-3), and Sigmas for Au at 40 mK and 55 mK are 2.2 x 10(9) WK-5 m(-3) and 3.2 x 10(9) WK-5 m(-3), respectively.