Design of the Notre Dame recoil separator

The study of low energy radiative capture reactions is of prime interest for many nuclear astrophysics scenarios. While many measurements have been made using various setups in direct kinematics, the very small cross section of these reactions at astrophysically interesting energies, along with the beam induced background, limit the possible range of measurements. A facility for measuring cross sections of radiative 4He capture in inverse kinematics has been designed. This 20 m long recoil mass separator (St. George) will be coupled to the KN Van de Graaff accelerator at the University of Notre Dame. The goal of St. George is to separate a low mass (A⩽40)(A⩽40), low energy (E<0.5MeV/A), high intensity (∼100μA) beam from the few reaction products emerging from a windowless 4He jet gas target. The desired acceptance is Δθ=±40mrad and ΔE/E=±7.5%ΔE/E=±7.5%.