Speaker
Dr
Gianpiero Gervino
(Dipartimento di Fisica and INFN Torino)
Description
To precisely determine BBN 6Li production, the cross section of the nuclear reaction $^2$H(α,γ)$^6$Li must be directly measured within the astrophysical energy range of 30-400 keV.
Since the cross section is of the order of nanobarn, the expected counting rate is very low indeed, therefore this measurement requires an ultra-low γ-ray background in the experimental set-up.
We have realized the conditions matching these very strict requirements at LUNA, the deep underground accelerator laboratory active in the INFN Gran Sasso National Laboratory (LNGS), Italy, exploiting 1400 m of rock as a powerful passive shield from cosmic ray. This leads to a reduction of the muon flux, the most penetrating component of the cosmic-rays, by a factor 106 compared to the surface. At LUNA is running an electrostatic continuous beam 400 kV accelerator that provides an α beam of 0.3 mA of average luminosity.
The nuclear reactions are induced in a windowless differentially pumped gas target filled
with up to 0.3 mbar high purity deuterium gas, with on-line feed back control of gas pressure.
We present and discuss the γ-ray background reduction reached in the HPGe spectrometer.
Collaboration
for the LUNA Collaboration
Primary author
Dr
Gianpiero Gervino
(Dipartimento di Fisica and INFN Torino)
Co-author
Dr
Carlo Gustavino
(INFN Sez. ROMA1)
