Fluorescent Detectors on Auger Site

There are 4 buildings with 6 fluorescence telescopes each that overlook the area of SD stations (Fig. 1). Each telescope uses Schmidt optics and consists of a wide-angle, segmented spherical mirror, a spherical focal plane, a UV 300-410 nm passband filter, and a refractive corrector ring at the aperture of the telescope. The telescope field of view is 30◦ (in azimuth) x 28◦ (in elevation) so each building has 180◦ azimuth range (the 3 high-elevation telescopes observe 30◦ to 60◦ in elevation). There are 440 photomultipliers in the focal plane which collect reflected light. The longitudinal profile of a shower is thus measured as an image of active PMT pixels along the shower axis. The layout of the FD geometry is shown in Fig. 3.

arXiv