Submillimeter Camera Set to Scan the Universe

The world’s largest submillimeter camera is now ready to scan the universe, including faint and faraway parts never before seen. Mounted on the James Clerk Maxwell Telescope on Mauna Kea, the instrument will advance studies of the origins of stars, planets and galaxies.

The new 4.5-ton camera, called SCUBA-2, contains more than 10,000 superconducting sensors and is far more sensitive than its predecessor SCUBA (Submillimeter Common-Use Bolometer Array). It will map the sky hundreds of times faster and with a much larger field of view than its predecessor, while producing better images, imaging new targets, and supporting deeper and broader surveys.

The SCUBA-2, mounted on the James Clerk Maxwell Telescope, is the largest submillimeter-wave camera yet made. (Photo: Joint Astronomy Centre)

SCUBA-2 will image objects ranging from comets in the Earth’s solar system to galaxies at the far ends of the universe. The camera is sensitive to objects associated with clouds of very cold gas and dust, which absorb visible light (and therefore look black to optical telescopes) but emit the barest whiffs of radiation with wavelengths below 1 mm — between the microwave and infrared bands.

“The submillimeter is the last frontier in astronomical imaging,” said Gene Hilton of the National Institute of Standards and Technology (NIST), which developed the superconducting sensors for the instrument. “It’s been very difficult to develop cameras that work at this wavelength, so the submillimeter is largely unexplored. We’re excited to see what SCUBA-2 will reveal.”

SCUBA-2 complements other observatories. For instance, its ability to quickly carry out large-scale surveys could identify targets for high-resolution studies by the Atacama Large Millimeter/submillimeter Array, a complex of radiotelescope dishes recently unveiled in Chile.

The NIST sensors precisely measure submillimeter radiated power using a superconducting metal, molybdenum-copper, that changes resistance in response to heat from radiation. Each tiny sensor functions as a single pixel in the camera. In sheer numbers of pixels, the NIST instrument is the largest superconducting camera ever made, although its physical size is only about 30 sq in. divided into two areas targeting different wavelengths. SCUBA-2 can detect light at 450 and 850 μm.

The NIST sensor arrays are packaged with superconducting amplifiers to boost signal strength. The sensors and amplifiers are cooled to cryogenic temperatures near absolute zero. NIST physicist Kent Irwin, who invented the sensor technology, worked with Hilton and other NIST researchers to develop a way of linking the amplifiers to make large-scale sensor arrays practical, greatly reducing the number of wires between the cryogenic instruments as well as the room-temperature electronics used to compile the data.

The James Clerk Maxwell Telescope is the largest single-dish submillimeter-wave telescope. It is operated by the Joint Astronomy Centre, on behalf of the UK Science and Technology Facilities Council (STFC), the Canadian National Research Council and the Netherlands Organisation for Scientific Research.

For more information, visit: www.stfc.ac.uk