High precision measurement of the 3He(4He,γ)7Be reaction at LUNA

The 3He(4He,γ)7Be reaction represents the key process for the production of 7Be and 8Be neutrinos in the Sun. We have designed a new experimental setup to study this reaction with high accuracy at low energies using two different experimental techniques. The first method consists in measuring the prompt capture gamma-ray transitions with an ultra-low background germanium detector heavily shielded and placed at close distance from a 3He windowless gas target. With another fully shielded large volume germanium detector we will also measure the beta-decay of the 7Be residual nuclei. The aim of the experiment is to reduce the error on the astrophysical factor S(3,4) to about 4%. These results will allow to study the central region of the Sun with an accuracy better than the one obtained by helioseismology. (author)