Development of a compact dual-frequency SIS receiver

Of particular interest for the 14 m millimeter-wave telescope at Delingha (PMO, China) is to observe J=1-0 and 2-1 transitions of carbon monoxide (as well as those of their isotopes), which give rise to emissions at frequencies of around 115 and 230 GHz, respectively. Incorporated with a modified two-stage Gifford-McMahon (GM) 4-K refrigerator, a compact dual-frequency (100- and 230GHz) SIS (superconductor-insulator-superconductor) receiver is developed. Experimental results upon the 4-K cryogenic system and the 100 GHz SIS receiver are presented.