Test and integration results from SuperCam: a 64-pixel array receiver for the 350 GHz atmospheric window

Abstract

Abstract-We report on laboratory testing and telescope integration of SuperCam, a 64 pixel imaging spectrometer designed for operation in the astrophysically important 870 micron atmospheric window. SuperCam will be used to answer fundamental questions about the physics and chemistry of molecular clouds in the Galaxy and their direct relation to star and planet formation. The Supercam key project is a fully sampled Galactic plane survey covering over 500 square degrees of the Galaxy in 12 CO(3-2) and 13 CO(3-2) with 0.3 km/s velocity resolution.SuperCam will have several times more pixels than any existing spectroscopic imaging array at submillimeter wavelengths. The exceptional mapping speed that will result, combined with the efficiency and angular resolution provided by the HHT will make SuperCam a powerful instrument for probing the history of star formation in our Galaxy and nearby galaxies. SuperCam will be used to answer fundamental questions about the physics and chemistry of molecular clouds in the Galaxy and their direct relation to star and planet formation. Through Galactic surveys, particularly in CO and its isotopomers, the impact of Galactic environment on these phenomena will be realized. These studies will serve as "finder charts" for future focused research (e.g. with ALMA) and markedly improve the interpretation, and enhance the value of numerous contemporary surveys.In the past, all heterodyne focal plane arrays have been constructed using discrete mixers, arrayed in the focal plane. SuperCam reduces cryogenic and mechanical complexity by integrating multiple mixers and amplifiers into a single array module with a single set of DC and IF connectors. These modules are housed in a closed-cycle cryostat with a 1.5W capacity 4K cooler. The Supercam instrument is currently undergoing laboratory testing with four of the eight mixer array modules installed in the cryostat (32 pixels). Work is now underway to perform the necessary modifications at the 10m Heinrich Hertz Telescope to accept the Supercam system. Supercam will be installed in the cassegrain cabin of the HHT, including the optical system, IF processing, spectrometers and control electronics. Supercam will be integrated with the HHT during the 2009-2010 observing season with 32 pixels installed. The system will be upgraded to 64 pixels during the summer of 2010 after assembly of the four additional mixer modules is completed.

Time-Delay Multiplexing of Two Beams in a Terahertz Imaging Radar

“…However, shortening the image acquisition time of a terahertz radar from its current timescale of 1 min to less than 1 s is a major challenge. The natural path to achieving high frame rates is to fabricate a focal plane array that projects and detects multiple radar beams simultaneously, but terahertz heterodyne transceiver arrays [4], [5] have not yet been realized because of the cost and complexity of constructing many parallel submillimeter-wave sources and receivers.…”

Efficiency of multi-beam Fourier phase gratings at 14 THz

“…Although waveguide based multiple beam generators [12,13] may provide high efficiency, very few experiments are found in the literature. Furthermore, manufacturing of the waveguides, in particular, at the supra-THz frequency range (>1 THz), such as the frequency band centered at 4.7 THz, which is significant for astronomical applications, becomes increasing difficult and costly.…”

The Kilopixel Array Pathfinder Project (KAPPa), a 16 pixel integrated heterodyne focal plane array

“…The current state-of-the-art pixel count for coherent THz arrays is 64 pixels (i.e. SuperCam, [4]) or less. While these instruments are a great leap forward from single pixel detectors, the pixel count is still inadequate for wide field THz imaging of weak spectral lines.…”