Elastic scattering of ³He + α with SONIK

Elastic scattering of ³He + α is of interest in analyses of ³He(α,γ)⁷Be, which has broad importance in big bang nucleosynthesis and solar neutrino physics. Phenomenologically, α(³He,³He)α can be used in global R-matrix analyses to extrapolate the ³He(α,γ)⁷Be astrophysical S-factor (S₃₄) to energies of astrophysical interest. With respect to solar physics, ³He(α,γ)⁷Be, the initial reaction in the pp-II and pp-III chains, leads to the production of ⁷Be and ⁸B. Consequently, at solar energies S₃₄ is almost directly proportional to the flux of ν_e emitted in the subsequent β - decays of ⁷Be and ⁸B. Thus it is critical to know S₃₄ to a high degree of accuracy and precision.

 ³He + α elastic scattering was measured using the recently commissioned Scattering of Nuclei in Inverse Kinematics (SONIK) scattering chamber, a windowless, extended gas target surrounded by an array of collimated, ion implanted silicon charged particle detectors situated at TRIUMF, ISAC-I. Experimental techniques and preliminary results will be discussed.