KM3NeT: Optimization studies for a cubic kilometer neutrino detector

In the KM3NeT Collaboration an important task is the simulation of the detector performance which aims at the optimization of the detector design. In this work the effect of two important items are studied: the PMT photocathode quantum efficiency and the effect of the bar length of a three-dimensional detection units. Simulation studies including the improved PMT photocathode quantum efficiency show that, especially at energy below 100 TeV, the increasing of the neutrino effective area is important. Moreover, simulations that optimize the geometry of one of the detection units proposed in KM3NeT are presented. In particular an increase in the effective areas for longer bars is observed.