Large Area Solar Power Heliostat Arrays for OSETI
Corbin E. Covault
Current OSETI programs make use of optical telescopes with light collection areas on the order of 10 square meters or less. The small collection area limits the ultimate sensitivity achievable to low-intensity signals. However, solar power facilities such as the National Solar Thermal Test Facility (NSTTF) provide the potential for a much larger collecting area. The NSTTF is operated by the Department of Energy at Sandia National Laboratories for research in solar power development and testing. The NSTTF site includes over 200 fully trackable mirrors (called heliostats) each providing 37 square meters of collecting area. This facility is currently being used at night for gamma-ray astronomy. The STACEE experiment makes use of 64 heliostats to detect nanosecond flashes of optical Cherenkov light associated with gamma-ray air showers from the top of the atmosphere. The STACEE experiment has been in operation since 1998 and has already detected gamma-rays from the Crab Nebula. In principle, the STACEE experiment can be operated with minor modifications to detect OSETI signals on the ground at a photon density of less than two optical photons per square meter per pulse. We summarize performance results from the STACEE experiment, and we discuss the sensitivity of a hypothetical future STACEE-OSETI experiment with particular attention to potential sources of background.
OSETI, Heliostat Mirrors, Cherenkov Detectors.
Corbin Covault received his Ph.D. in physics from Harvard in 1990. He is a member of the physics department at the University of Chicago. His research is in the area of experimental high energy astrophysics and the development of new instruments for ground-based detection of high energy cosmic rays and gamma-rays.
Department of Physics,