Development of Submillimeter-wave Camera using SIS Photon Detectors

点击翻译按钮获取中文摘要

Development of submillimeter-wave SIS photon detector is performed using superconducting niobium junctions to realize wide-field and wide-bandwidth observations in submillimeter-wave. We have also made 3-color bolometer system operating at 350,650 and 850 GHz to start submilllimeter-wave continuum observations with ASTE (Atacama Submillimeter Telescope Experiment) submillimeter telescope.In the first year of development, we have successfully fabricated low leakage, less than 10 pA, tunnel junction with 1kA/cm2 current density by optimizing the fabrication conditions. In the next year we have observed submillimeter-wave response at 440 GHz and 650 GHz using 4 micron and 3 micron diameter junctions, respectively. In the last year, we have evaluated the detector performance, such as leakage current, current noise, voltage responsivity, quantum efficiency, linearity, time constant and beam pattern with optics. NEP shows 10(-16)W/sqrt(Hz). The measured performance is superior to submillimeter-wave bolometers. The fabrication yield is improve to be 98% for single junctions and 78% for detector elements.The 3-color bolometer system is developed to make early continuum observations with ASTE telescope and to evaluate the antenna performance. Cryostat for 0.3 K operations is developed to realize remotely operable low vibration cryogenics. We have started scientific observing runs with the bolometric receivers.