In this review we rst address 2 questions: why do we need kilometer-scale muon and neutrino detectors? what do we learn from the operating Baikal and AMANDA detectors about the construction of kilometer-scale detectors? I will subsequently discuss the challenges for building the next-generation detectors. The main message is that these are diierent, in fact less ominous, than for commissioning ...

Modification of large water Cherenkov detectors by addition of gadolinium has been proposed. The large cross section for neutron capture on Gd will greatly improve the sensitivity to antielectron neutrinos from supernovae and reactors. A five-year project to build and develop a prototype detector based on Super-Kamiokande (SK) has started. We are performing various studies, including a material...

The novel idea of water Cherenkov calorimeter made of water tanks as the next generation neutrino detector for ν factories and ν beams is investigated. A water tank prototype with a dimension of 1×1×13m is constructed, its performance is studied and compared with a GEANT4 based Monte Carlo simulation. By using measured parameters of the water tank, including the light collection efficiency, att...

Milagro is a unique water Cherenkov detector designed for very high energy (VHE) gamma-ray astronomy. The water Cherenkov technique gives Milagro an unprecedented sensitivity and energy threshold. A deep detector layer is used to identify penetrating particles (muons and hadrons) present in hadron induced showers allowing for the rejection of backgrounds which substantially increases sensitivit...

The dependence of the lateral distribution of Cherenkov light in simulated extensive air showers to the energy and the mass of the primary cosmic rays has been studied. It has been shown that a previous claim about mass independent proportionality of shower energy to the total Cherenkov photon number is not valid in energies below EEAS ~ 1014 eV. We have found that the core distance of the so c...

Simulation of gamma and hadron showers in the energy range 100GeV- 25TeV has been carried out. For a big ideal Cherenkov light array, characteristics of lateral distribution of Cherenkov photon density have been studied. Results from this ideal detector are compared with those simulated for a real TUNKA- like array to investigate experimental potential of using existence of a hump in lateral di...