Towards a high-precision measurement of the 3He(α γ) 7Be cross section at LUNA

Abstract

The 3 He( 4He, γ) 7 Be reaction is the key process for the production of 7 Be and 8 B 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 3 He windowless gas target. With another fully shielded large-volume germanium detector we will also measure the ß-decay of the Be residual nuclei. The aim of the experiment is to reduce the error on the astrophysical factor S 3,4 to 4%.