Upgrading ANASEN for ¹⁸Ne(α,p)²¹Na direct measurement

The Array for Nuclear Astrophysics and Structure with Exotic Nuclei (ANASEN) is a gas target and charged particle detector designed for studying (α,p) reactions. Previous measurements used a position-sensitive proportional counter along the beam axis with a barrel of thick silicon detectors far from the beam axis to track protons from these reactions. We have developed a new approach, replacing the proportional counter with a hexagonal barrel of thin silicon detectors. This allows pure helium gas to be used and improves the tracking resolution, though at a cost of overall efficiency. The performance in stable beam test measurements will be presented with a preliminary report on a direct measurement at TRIUMF of the ¹⁸Ne(α,p)²¹Na excitation function.