Speaker
Description
The Fluorescence Detector (FD) of the Pierre Auger Observatory provides energy measurements of primary cosmic rays that are largely independent of specific interaction models. These measurements are crucial for calibrating the energy reconstruction of the Surface Detector. Consequently, the accuracy of the FD energy calibration plays a key role in the systematic uncertainties associated with nearly all scientific results of the Observatory.
To this end, a laser with a well-defined pulse energy will be fired into the field of view of the FD telescopes. Unlike other calibration methods, the response of the telescopes to the laser closely simulates the response to an actual cosmic-ray air shower. The system was designed with special attention to the depolarization of the laser beam to ensure a consistent relationship between laser energy and directional light yield.
This contribution presents results from laboratory measurements of the laser system, which were performed to validate and optimize its performance before field deployment. In addition, we present results from the first in-field tests of the system at the Pierre Auger Observatory in Argentina.
