Present status and future prospects of underground nuclear astrophysics

A 50 kV accelerator has been installed by the LUNA Collaboration in the underground laboratories of the Laboratori Nazionali del Gran Sasso (LNGS) in Italy making it possible for the first time to determine the cross-section of the reaction 3He(3He,2 p)4He in the thermal energy region of the Sun. As a next step the LUNA Collaboration will build a new facility at the LNGS). It will consist of a 400kV accelerator with gas and solid target stations at a low background detector set up for gamma-spectroscopy. The system will offer the possibility to study the other key reactions of the pp-chain at very low energies. In addition the reactions of the other hydrogen burning phases such as the NeNa and the MgAl cycles can be investigated