The 3He(4He,γ) 7Be reaction plays an important role in determining the high energy solar neutrino flux and in understanding the abundances of primordial 7Li. This Letter reports a new precision measurement of the cross sections of this direct capture reaction, determined by measuring the ensuing 7Be activity in the region of Ec.m.=420 to 950 keV. Various recent theoretical fits to our data result in a consistent extrapolated value of S34(0)=0.53(2)(1) keV b.
Nara Singh, B. S., Hass, M., Nir-El, Y., & Haquin, G. (2004). New precision measurement of the 3He(4He,γ) 7Be cross section. Physical Review Letters, 93, . https://doi.org/10.1103/PhysRevLett.93.262503