Brookhaven Completes LSST’s Digital Sensor Array

Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have completed a 3.2-gigapixel sensor array for the camera that will be used in the Large Synoptic Survey Telescope (LSST) currently under construction on a mountaintop in Chile.

Members of the LSST project team at Brookhaven Lab are shown with a prototype raft cryostat. In addition to the rafts, Brookhaven scientists designed and built the cryostats that hold and cool the rafts to −100 °C. Courtesy of Brookhaven National Laboratory.

The digital sensor array is composed of about 200 16-megapixel sensors, divided into 21 modules called rafts. Each raft can function on its own, but when combined, they will view an area of sky that can fit more than 40 full moons in a single image. Researchers will stitch these images together to create a time-lapse movie of the complete visible universe accessible from Chile.

Scientist Paul O’Connor said that the array, which is 3 billion pixels, is the biggest charge-coupled device (CCD) array ever built.

SLAC National Accelerator Laboratory installs the first of Brookhaven’s 21 rafts that make up LSST's digital sensor array. Courtesy SLAC National Accelerator Laboratory.

The project to build the telescope facility and camera is a collaborative effort among more than 30 institutions from around the world and is primarily funded by the DOE’s Office of Science and the National Science Foundation (NSF). DOE’s SLAC National Accelerator Laboratory is leading the overall effort to construct the camera — the world’s largest for astronomy — while Brookhaven is guiding the design, construction, and qualification of the digital sensor array, which will serve as the “digital film” for the camera.

The Brookhaven team has tested each fully assembled raft, as well as individual sensors and electronics. Now, just two years after the start of raft production, the team has successfully built and shipped the final raft to SLAC for integration into the camera. This marks the end of a 16-year project at Brookhaven, which will be followed by many years of astronomical observation.

Brookhaven Lab will continue to play a strong role in LSST going forward. As the telescope undergoes its commissioning phase, Brookhaven scientists will serve as experts on the digital sensor array in the camera. They will also provide support during LSST’s operations, which are projected to begin in 2022.

Once operational in the Andes Mountains, LSST will serve nearly every subset of the astrophysics community. Perhaps most importantly, LSST will enable scientists to investigate dark energy and dark matter. It is also estimated that LSST will find millions of asteroids in our solar system, in addition to offering new information about the creation of our galaxy.