2H(p, γ)3He cross section measurement using high-energy-density plasmas

An absolute cross section for the radiative capture reaction H-2(p, gamma)He-3 has been measured at the OMEGA laser facility using inertially confined plasmas. These high-temperature plasmas are created by imploding a fuel-containing capsule using laser ablation, and are advantageous in that they better mimic astrophysical systems. We measure an S factor for this reaction of 0.429 +/- 0.026(stat) +/- 0.072(sys) eV b at E-c.m. = 16.35 +/- 0.40 keV, which is higher than the adopted evaluations. This reaction is important as a source of nuclear energy in protostars and brown dwarfs. It is also a critical reaction during big-bang nucleosynthesis, and an accurate cross section can be used as a constraint on cosmology.