GaAs cryogenic readout electronics for high impedance detector arrays for far-infrared and submillimeter wavelength region

We have been developing cryogenic readout integrate circuits (ROICs) for high impedance submillimeter and far-infrared detectors: Our ROICs are constructed from SONY GaAs-JFETs, which have excellent performance even at less than 1 K. We designed ROICs consisting of analog readouts and digital circuits for 32-element SIS photon detectors fabricated in RIKEN. The analog readout is ac-coupled capacitive transimpedance amplifier (CTIA), which is composed of the two-stage amplifier. Some initial test results of the ac-coupled CTIA gave us the following performance; open loop gain of >740, power consumption ≈1.4 μW. The input referred noise is ≈4 μV/Hz at 1 Hz. These results suggest that low power and high sensitive cryogenic readout electronics are successfully developed for high impedance detectors.