To increase the sensitivity for detection of solar neutrinos and
Supernova relic neutrinos by the Cherenkov radiation in the
Hyper-Kamiokande detector it is proposed to use light collectors (mirrors)
surrounding PMTs. The simulation of the light collectors was done. An
increase in the efficiency of neutrino registration for different mirror
shapes and sizes was investigated, as well as negative effects associated
with the reflection of Cherenkov light.