Piatti D. Web of Conferences. EDP Sciences, 2022, 260, 11027.
Measurements of the 6Li(p,γ)7Be reaction cross section at low energies have yielded conflicting results regarding the slope of the astrophysical S-factor. In this study, the cross section for the 6Li(p,γ)7Be reaction was determined within the energy range of Ec.m. = 60-350 keV with exceptional sensitivity, and no indications of the purported resonance were observed.
Experimental Setup
· This study conducted a novel experiment deep underground. The LUNA-400 accelerator generated a high-intensity proton beam, which was collimated using a 3 mm diameter aperture and transmitted through a copper pipe to a target positioned at a 55° angle relative to the beam. The copper tube served a dual purpose, functioning as both a cold trap and a means for suppressing secondary electrons.
· The experiment included three targets, two made from 6Li2WO4 powder with thicknesses ranging from 100 to 200 µg/cm², and one target with a thickness of 20 µg/cm² created from lithium-6 oxide (6Li2O) powder. All targets had a 95% isotopic enrichment of 6Li and were cooled with water during irradiation to prevent degradation.
· To detect the γ rays from the 6Li(p,γ)7Be reaction, a High-Purity Germanium (HPGe) detector was positioned in close proximity to the target at a 55° angle to the beam. Simultaneously, a silicon detector was installed at 125° from the beam's direction to detect α and 3He particles from the 6Li(p,α) 3He reaction alongside the gamma rays from the 6Li(p,γ)7Be reaction. The detection efficiencies for both detectors were obtained through GEANT simulations and refined by comparing them to experimental results.
