In the last five years, new discoveries by satellite and ground-based
telescopes have revolutionized our understanding of gamma-ray
astrophysics. We now know that a large number of astrophysical
sources accelerate particles to GeV energies; in some cases the
energies exceed 10 TeV. High energy gamma-ray observations of such
objects will help us understand these powerful accelerators. They may
also tell us something about the structure of the intergalactic IR
radiation field, the nature of the dark matter, and the possibility of
long-lived relic particles.
To date, no experiments have operated in the gamma-ray energy window
between 20 and 250 GeV. STACEE is an experiment under construction
which will carry out the first observations in this window. STACEE
will use large heliostat mirrors at a solar research facility (Sandia
National Labs) to collect atmoshperic Cherenkov radiation from air
showers created by high energy gamma-rays. This talk with discuss the
scientific motivation and current progress of STACEE.
