Absolute calibration of the Auger Fluorescence Detectors

P. BAULEO, J. BRACK, L. GARRARD, J. HARTON, R. KNAPIK, R. MEYHANDAN, A.C. ROVERO, A. TAMASHIRO, AND D. WARNER, FOR THE AUGER COLLABORATION

Pune, India

Conferencia; 29th International Cosmic Ray Conference; 2005

University of Pune. Tata Institute of Fundamental Research, Mumbai.

Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a light source at the telescope aperture. The technique accounts for the combined effects of all detector components in a single measurement. The calibrated 2.5 m diameter light source fills the aperture, providing uniform illumination to each pixel. The known flux from the light source and the response of the acquisition system give the required calibration for each pixel. In the lab, light source uniformity is studied using CCD images and the intensity is measured relative to NIST-calibrated photodiodes. Overall uncertainties are presently 12%, and are dominated by systematics.