Jeffrey Steinberg with Corbin Covault

Moonlight Calibration of STACEE-64 Optical System

The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is an experiment designed to measure gamma ray sources ranging from 40GeV to 250GeV in energy from the universe via the interaction of the gamma rays with the atmosphere.  These interactions result in Cherenkov light showers which can be detected with the STACEE apparatus.  The STACEE apparatus consists of an array of 212 mirrors that reflect light to a tower which focuses the light onto a detector with only 64 of the 212 mirrors actually used in the experiment.  We will perform a calibration of the end-to-end optical throughput of the STACEE gamma ray telescope experiment using the full moon as a light source.  This calibration will be compared to the predictions given by Monte Carlo simulations, and it will involve the use of narrow band filters and photomultiplier tubes that will allow us to determine the throughput as a function of wavelength.  The measurements determined in the moon calibration are directly related to the energy of the incoming gamma ray which determines the mean density of Cherenkov photons on the ground.