On the Road to the Solution of the Solar Neutrino Problem

The present status of the Homestake, GALLEX, SAGE, and Kamiokande solar neutrino experiments will be reviewed. The discrepancy between all of the experimental results and the theoretical expectations has come to be known as the Solar Neutrino Problem. Possible solutions to this problem will be discussed. The next generation of solar neutrino experiments will be described. Among these is the Sudbury Neutrino Observatory (SNO), which will consist of a 1000 tonne heavy water (D₂O) Cerenkov detector that is designed to measure the flux, energy spectrum, and direction of neutrinos from the Sun and supernovae. It is presently under construction in a very low background environment 2000 meters underground near Sudbury, Ontario, Canada. The basic measurements that will be made with the SNO detector are:

• the flux and energy spectrum of electron-type neutrinos reaching the Earth, and
• the total flux of all neutrino types above an energy of 2.2 MeV.

• determine if neutrino oscillations occur, and
• independently test solar models by determining the production rate of high energy electron-type neutrinos in the solar core.