An update on the SCUBA-2 project

Abstract

SCUBA-2, which replaces SCUBA (the Submillimeter Common User Bolometer Array) on the James Clerk Maxwell Telescope (JCMT) in 2006, is a large-format bolometer array for submillimeter astronomy. Unlike previous detectors which have used discrete bolometers, SCUBA-2 has two dc-coupled, monolithic, filled arrays with a total of ∼10,000 bolometers. It will offer simultaneous imaging of a 50 sq-arcmin field of view at wavelengths of 850 and 450 µm. SCUBA-2 is expected to have a huge impact on the study of galaxy formation and evolution in the early Universe as well as star and planet formation in our own Galaxy. Mapping the sky to the same S/N up to 1000 times faster than SCUBA, it will also act as a pathfinder for the new submillimeter interferometers such as ALMA. SCUBA-2's absorber-coupled pixels use superconducting transition edge sensors operating at 120 mK for performance limited by the sky background photon noise. The monolithic silicon detector arrays are deep-etched by the Bosch process to isolate the pixels on silicon nitride membranes. Electrical connections are made through indium bump bonds to a SQUID time-domain multiplexer (MUX). We give an overview of the SCUBA-2 system and an update on its status, and describe some of the technological innovations that make this unique instrument possible.

The kilopixel array pathfinder project (KAPPa), a 16-pixel integrated heterodyne focal plane array: characterization of the single pixel prototype

“…Two techniques are used to measure THz radiation: cryogenic bolometers and coherent receivers. At longer THz wavelengths, ~450-850 microns, the cryogenic bolometer UK SCUBA2 instrument, with 10,240 pixel, is now employed at the 15m James Clerk Maxwell Telescope [1]. While SCUBA2 will likely revolutionize the field in a similar manner as its predecessor, it is inherently incapable of measuring specific gas line emissions.…”

Far infrared through millimeter backshort-under-grid arrays

“…Two examples of bolometer array designs that exceed 1000 pixels are the tiled bolometer arrays for Herschel/Photodetector Array Camera and Spectrometer (PACS), and the over 4000 pixel array for SCUBA-2. 5,6 The PACS arrays are a mosaic of 16×16 semiconductor bolometer arrays. 7 As mentioned before, a path to directly scaling semiconductor bolometer to kilopixel formats does not yet exist.…”

Automatic setup of SCUBA-2 detector arrays

“…The next major development will be the introduction of a new generation of detectors using superconducting Transition-edge Sensors (TES). Bolometer cameras based on TES [2][3] will provide the high sensitivity and high mapping speed needed to perform precision cosmic microwave background measurement and accurate characterisation of extra-galactic sub-mm galaxies [4]. SCUBA-2 has two focal planes, one for working at a wavelength of 850um and the other at a wavelength of 450um [5].…”