The

Neutron-capture processes made most of the abundances of heavy elements in the Solar System, however they cannot produce a number of rare proton-rich stable isotopes (p–nuclei) lying on the left side of the valley of stability. The γ–process, i.e., a chain of photodisintegrations starting on heavy nuclei, is recognized and generally accepted as a feasible process for the synthesis of p–nuclei in core collapse supernovae (CCSNe). However this scenario still leaves some puzzling discrepancies between theory and observations. We aim to explore in more detail the γ–process production from massive stars, using different sets of CCSNe models and the latest nuclear reaction rates. Here we show our preliminary analysis, by identifying the γ–process sites and focusing on progenitors of CCSNe that experience a C–O shell merger just before the collapse of the Fe core

Experimental study of proton-induced nuclear reactions in 6,7 Li

The 6Li(p,α)3He and 7Li(p,α) 4He reaction cross sections were obtained for E = 90-580 keV and E = 90-1740 keV, respectively. R-matrix and polynomial fits to the bare astrophysical S-factor confirmed, with improved accuracy, previous work data, yieldin

Off-line production of a 7Be radioactive ion beam

A Be-7 ion beam of several particle pA at 8 MeV has been produced at the TTT3 tandem of the University "Federico II" in Naples. The Be-7 nuclides were formed via the Li-7(p,n)Be-7 reaction using a metallic Li target and an 11.4 MeV proton beam of 20 muA intensity, delivered by the cyclotron in Debrecen. Methods of hot chemistry were used to extract the Be-7 nuclides from the Li matrix and to prepare the Be-7 cathodes for the ion sputter source of the tandem

Advances in radiative capture studies at LUNA with a segmented BGO detector

Studies of charged-particle reactions for low-energy nuclear astrophysics require high sensitivity, which can be achieved by means of detection setups with high efficiency and low backgrounds, to obtain precise measurements in the energy region of interest for stellar scenarios. High-efficiency total absorption spectroscopy is an established and powerful tool for studying radiative capture reactions, particularly if combined with the cosmic background reduction by several orders of magnitude obtained at the Laboratory for Underground Nuclear Astrophysics (LUNA). We present recent improvements in the detection setup with the Bismuth GermaniumOxide (BGO) detector at LUNA, aiming to reduce high-energy backgrounds and to increase the summing detection efficiency. The new design results in enhanced sensitivity of the BGO setup, as we demonstrate and discuss in the context of the first direct measurement of the 65 keV resonance (Ex = 5672 keV) of the 17O(p, γ)18F reaction. Moreover, we show two applications of the BGO detector, which exploit its segmentation. In case of complex γ-ray cascades, e. g. the de-excitation of Ex = 5672 keV in 18F, the BGO segmentation allows to identify and suppress the beam induced background signals that mimic the sum peak of interest. We demonstrate another new application for such a detector in form of in-situ activation measurementsof a reaction with β+ unstable product nuclei, e. g., the 14N(p, γ)15O reactio