Setup commissioning for an improved measurement of the D(p,$$\gamma $$)$$^3$$He cross section at Big Bang Nucleosynthesis energies

Abstract

Among the reactions involved in the production and destruction of deuterium during Big Bang Nucleosynthesis, the deuterium-burning D(p,γ) 3 He reaction has the largest uncertainty and limits the precision of theoretical estimates of primordial deuterium abundance. Here we report the results of a careful commissioning of the experimental setup used to measure the cross-section of the D(p,γ) 3 He reaction at the Laboratory for Underground Nuclear Astrophysics of the Gran Sasso Laboratory (Italy). The commissioning was aimed at minimising all sources of systematic uncertainty in the measured cross sections. The overall systematic error achieved (< 3%) will enable improved predictions of BBN deuterium abundance.

The baryon density of the Universe from an improved rate of deuterium burning

“…We bombarded a high-purity deuterium gas target 10 with an intense proton beam from the LUNA 400 kV accelerator 11 and detected the γ rays from the nuclear reaction under study with a high-purity germanium detector. Our experimental results settle the most uncertain nuclear physics input to BBN calculations and substantially improve the reliability of using primordial abundances as probes of the physics of the early Universe.…”

“…The new measurement of the D(p,γ) 3 He cross section discussed in this paper was performed at the LUNA-400kV accelerator , a world-leading facility to study nuclear reactions at the lowest energies frontier of nuclear astrophysics. The million-fold reduction in cosmic-ray muons of the deep-underground location 8 and a careful commissioning 10 of the experimental setup aimed at minimising all sources of systematic errors have led to D(p,γ) 3 He cross-section data of unprecedented precision and with overall uncertainties below 3% over the measured energy region (E = 32 − 263 keV), relevant to BBN energies (E = 30 − 300 keV, see Methods). As shown in Figure 1, the new data represent a significant improvement compared to previous work 14,15,17 .…”

Measurement of theH2(p,γ)He3STurkat1, Hammer2, Masha3 et al. 2021Phys. Rev. CSelf Cite80200View full textAdd to dashboardCite

“…In this energy range, which corresponds directly to the most important range for BBN (Fig. 8), there are no data from the present work, but there are the new high-precision gas target data from LUNA [23,46]. Within errors, the present data are not far from the new LUNA data points at similar energies.…”

“…Recently, there has been renewed interest in this energy region because of theoretical work using an ab initio approach resulting in an S factor that is about 10% higher than the SFII curve [22]. In this context, high-precision new data over most of the BBN range have very recently been reported from the LUNA underground ion accelerator in Gran Sasso [17,23].…”

The Study of Key Reactions Shaping the Post-Main Sequence Evolution of Massive Stars in Underground Facilities

“…The high current hydrogen and helium beams provided by the 50 kV (Greife et al, 1994) and, later on, by the LUNA-400 kV accelerators (Formicola et al, 2003) allowed for the investigation, for the first time at stellar energies, of the most important reactions responsible for the hydrogen burning in the Sun, such as 3 He( 3 He, 2p) 4 He (Bonetti et al, 1999), and for the BBN such as 2 H(p, c) 3 He (Casella et al, 2002;Mossa et al, 2020).…”