A 90 GHz array for use on the Green Bank Telescope

摘要

We are constructing an 8 x 8 bolometer camera, as a 90 GHz facility instrument for the 100 m Green Bank Telescope (GBT). The bolometers use transition-edge-superconducting (TES) sensors read out with a time-based SQUID multiplexing system. The receiver will be one of the first astronomical instruments to use such detectors. Our TES bolometers require cooling below 290 mK. To obtain these temperatures we use ~3He and ~4He sorption refrigerators that cycle from a two-stage pulse-tube cryocooler. The ~3He stage has an operating temperature of 252 mK and a hold time of 77 hours with a 10 μW load. A combination of the large collecting area of the GBT and the low noise of the detectors will enable us to map 15′ x 15′ areas of sky to 200 μJy in one hour.