Detection of GRB with water Cherenkov detectors

The detection of a high energy tail of photons from GRB should be possible with the single particle counting technique. A group of detectors would detect a higher rate of events on a short time scale, of the order of the second. This technique has already been used with plastic scintillators. Use of water Cherenkov detectors provides a main advantage with respect to scintillators by being sensitive to photons converting in the water. This should increase significantly the detection efficiency as the ratio photons to electrons in GRB photon showers is about 9 to 1 in the shower tail. The Pierre Auger observatory, with 1600 water Cherenkov detectors, could be a good candidate to check the efficiency of the technique. Similar detectors at higher altitude (Puebla 4500 m, Chacaltaya 5200 m) could bring better sensitivity to the high energy part of the GRB with much less surface to be covered.