Building telescopes to look at mysterious objects deep in space has spin-off applications that could be applied to detect nuclear weapons or in medical imaging.

UC Davis researchers led by physics professor Daniel Ferenc are among the 130 scientists from nine countries working on the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescope. Inaugurated in 2003 and located on the island of La Palma in the Canary Islands, MAGIC was built to open a new window on the universe by looking for objects that give off gamma rays, such as quasars, microquasars and supernovae.

MAGIC detects gamma rays by looking for flashes of light as the rays hit the upper atmosphere. As a result, MAGIC's primary detector surface actually is about 100,000 square meters of air, which it scans with its 240-square-meter mirror.

Part of the UC Davis contribution to the project has been to develop novel photosensors for detecting those flashes of light. Existing photosensors are based on vacuum tubes that are essentially hand-made, expensive and nearly impossible to produce in large enough quantities. Digital detectors like those used in digital cameras are too small for physics experiments where a very large area of detectors -- hundreds or even thousands of square meters -- is needed to capture very rare events, for example in neutrino astronomy, Ferenc said.

Ferenc's laboratory is developing detectors with a large photosensitive area that can be mass-produced, roughly similar to the flat panel displays now available for television sets. The surface of the detector would be coated with a thin, photosensitive semiconductor layer. When photons hit the surface, electrons are emitted inside the device and concentrated into a small detection area on the other side of the panel.

The technology also could be used to build drive-through scanning tunnels for checking cargo containers and vehicles for nuclear materials. By surrounding as much of the object to be scanned as possible, the scanner could pick up even very weak, spontaneous or neutron-induced signals that might be missed by a small or hand-held scanner, Ferenc said.

Another application could be to make cheaper medical body-scanning devices for use in hospitals or for research.

Ferenc is currently working on small-scale prototype devices using the technology, which has been patented. The work is supported by a grant from the U.S. Department of Energy's National Nuclear Security Administration.