The upGREAT heterodyne array receivers for far Infrared astronomy

Far Infrared Astronomy is one of the last explored fields in astronomy. Several bolometer cameras have already been developed with several hundred or more pixels and there is rapid progress in this area, however high resolution spectroscopy using heterodyne receivers have still not reached that level of maturity. Indeed, until now, only single pixel or small size arrays have been achieved in a handful of observatories. We present here upGREAT - two medium-size array receivers, operating cooled using closed-cycle pulse tube coolers. The Low Frequency Array (LFA) covers the 1.9-2.5 THz range using dual polarization 7-pixel HEB arrays. The second receiver, the High Frequency Array (HFA), will observe the O[I] line at ~4.7 THz using a 7-pixel HEB array.