Optical Filter Design for the Fluorescence Detector of the AUGER Project

The design concept of the required optical filters for the Fluorescence Detector of the AUGER Project, is presented in this work. Due to the needed high transmittance values in the UV region, the dielectric thin film multilayer technique, using UV-transparent materials, has been selected. The design method applied, is the “Monte Carlo Simulated Annealing” (MOCASA). Two alternative target spectral transmittance curves have been considered, as candidate for the optical filters. These are, the single-band pass and the multiband pass type, both covering the atmospheric nitrogen fluorescence spectral range. The design performance calculation, is based on the expected signal and the moonless night-sky background photon rates, selected by the optical filters. Characterizations of simple and double layres, using various candidate materials, are in progress, planning to produce a full prototype in near future.