TES Bolometers With High-Frequency Readout Circuit

In order to improve the frequency-division multiplexing (FDM) in transition edge sensor (TES) imaging arrays, it is suggested to replace commonly used SQUID amplifiers with a semiconductor high-frequency cooled amplifier. This would result in a single 10-GHz bandwidth amplifier serving the array of more than 1000 detectors. The basic idea is to implement an antenna-coupled TES as a load for a high-Q resonator, weakly coupled to a microwave transmission line. This high-frequency scheme substitutes the traditional wire connections to the TES. The NEP as low as 2 x 10(-19) W/Hz(0.5) is estimated at ambient temperature of 300 mK for submicron-size TES absorber made of Ti; the NEP is limited by 3 K noise temperature of the amplifier. To verify the new concept, prototype TES devices made of Nb are developed and tested above 4 K. The NEP of about 1.5 x 10(-15) W/Hz(0.5) is estimated for the experimental micron-size prototype devices made of Nb at 4.5 K. The IV-curves of the TES at different temperatures are recovered using the R(T) and heat balance models along with the experimental data; presence of the negative electrothermal feedback is verified.