SCUBA-2 is a second generation, wide-field submillimeter camera under development for the James Clerk Maxwell Telescope. With over 12,000 pixels, in two arrays, SCUBA-2 will map the submillimeter sky ~1000 times faster than the current SCUBA instrument to the same signal-to-noise. Many areas of astronomy will benefit from such a highly sensitive survey instrument: from studies of galaxy formation and evolution in the early Universe to understanding star and planet formation in our own Galaxy. Due to be operational in 2006, SCUBA-2 will also act as a "pathfinder" for the new generation of submillimeter interferometers (such as ALMA) by performing large-area surveys to an unprecedented depth. The challenge of developing the detectors and multiplexer is discussed in this paper.
A 350GHz 4 × 4 element heterodyne focal plane array using SIS detectors is presently being constructed for the JCMT. The construction is being carried out by a collaborative group led by the MRAO, part of the Astrophysics Group, Cavendish Laboratory, in conjunction with the UK-Astronomy Technology Centre (UK-ATC), The Herzberg Institute of Astrophysics (HIA) and the Joint Astronomy Center (JAC). The Delft Institute of Microelectronics & Sub-micron Technology (DIMES) is fabricating junctions for the SIS mixers that have been designed at MRAO.
Working in conjunction with the 'ACSIS' correlator & imaging system, HARP-B will provide 3-dimensional imaging capability with high sensitivity at 325 to 375GHz. This will be the first sub-mm spectral imaging system on JCMT - complementing the continuum imaging capability of SCUBA - and affording significantly improved productivity in terms of speed of mapping. The core specification for the array is that the combination of the receiver noise temperature and beam efficiency, weighted optimally across the array will be <330K SSB for the central 20GHz of the tuning range.
In technological terms, HARP-B synthesizes a number of interesting and innovative features across all elements of the design. This paper presents both a technical and organizational overview of the HARP-B project and gives a description of all of the key design features of the instrument. 'First light' on the instrument is currently anticipated in spring 2004.
SCUBA-2 is a second generation, wide-field submillimetre camera under development for the James Clerk Maxwell Telescope. With over 12,000 pixels, in two arrays, SCUBA-2 will map the submillimetre sky up to 1000 times faster than the current SCUBA instrument to the same signal-to-noise. Many areas of astronomy will benefit from such a highly sensitive survey instrument: from studies of galaxy formation and evolution in the early Universe to understanding star and planet formation in our own Galaxy. Due to be operational in 2006, SCUBA-2 will also act as a "pathfinder" for the new generation of submillimetre interferometers (such as ALMA) by performing large-area surveys to an unprecedented depth. The baseline design, projected telescope performance and scientific impact of SCUBA-2 are discussed in the paper.
This paper presents a science case for a wide-field camera operating at submillimetre wavelengths on an optical/infrared 100m Overwhelmingly Large Telescope (OWL). Such an instrument (dubbed "SCOWL" - a Submillimetre Camera for OWL) would offer an unprecedented simultaneous high angular resolution and imaging speed, and play a pivotal role in the future of submillimetre astronomy. Other proposed and existing facilities have either coarse resolution (current single dishes) or are relatively inefficient at carrying out large-scale survey work on a reasonable time scale (interferometers). Furthermore, if OWL is located at a dry high-altitude site, SCOWL will be able to exploit the relatively unexplored 200 and 350μm atmospheric windows with unparalleled efficiency. This is the regime where the emission from cold unevolved sources is at its peak, and is thus of unique scientific interest. By observing in the submillimetre, OWL will produce detailed, unbiased views of objects in formation, ranging from Solar-neighbourhood pre-stellar cores to proto-elliptical galaxies in the early Universe.
We describe the design and manufacture of SCUBA, which is undergoing laboratory testing prior to commissioning on the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. It contains two arrays, one of 91 pixels optimised for 450 micrometers and the second of 37 pixels optimised for 850 micrometers in close-packed arrays, with each pixel having diffraction-limited angular resolution. Some of the original design features of the instrument are described: the cryogenic system operating at 100mK; the optical layout; bolometer manufacture; and array integration. We illustrate the performance of the instrument with test results obtained during the laboratory commissioning.