Future solar neutrino projects

In the program to determine the intrinsic properties of the neutrinos and their role in physics and astrophysics, solar neutrino experiments are playing a fundamental part. The "first" and "second" generation detectors in the field have been enormously successful and promise to provide still greater contributions. The challenge to create a "third generation" of solar neutrino detectors arises principally from interest in making detailed investigations of the portion of the neutrino spectrum from a few keV to 1.5 MeV. That portion contains fluxes from the p-p and CNO continuum as well as the Be-7 and p-e-p lines. The need to overcome the experimental difficulties presented by working at these low energies have given rise to new ideas for detector technologies. The range of technologies is impressive in its variety and reflects choices of emphasis using real-time and radiochemical methods. In this paper, I present a review of the status of several R & D efforts known to me which are making progress toward providing detectors suitable to meet the various challenges of this low energy region.