The LIDRAE water-Cherenkov air shower array

We present the design, and preliminary results of the LIDRAE water-Cherenkov air shower array installed at UFABC ($23.6^\circ$S, $46.5^\circ$W, 750 m a.s.l.). LIDRAE detects the particles of extensive air showers with energies exceeding 100 TeV and is able to measure the arrival direction and energy of the primary cosmic rays. The array is composed of three tanks each filled with one thousand liters of water with a large aperture photomultiplier on the top cover of each tank overlooking the water volume. The photomultipliers detect the Cherenkov light generated by the passage of ultrarelativistic charged particles through the water. The produced signals are then sent to the data acquisition electronics where they are amplified, formatted, digitized and stored. The data are recorded in single and triple coincidence modes.