DAPPER Array Upgrade for Measuring ⁶⁰Fe Photon Strength Function via Radioactive Beam

A photon strength function (PSF) helps describes the excitation and de-excitation of the nucleus, which aids in the understanding of neutron capture reactions. Accurate neutron capture cross-sections are pertinent for modeling nucleosynthesis. The Detector Array for Photons, Protons, and Exotic Residues (DAPPER) is used to measure the PSFs of iron isotopes, important in the production of heavier elements, via (d,pγ) reactions. Alterations to the current array configuration are in progress in order to measure the PSF of ⁶⁰Fe, a long-lived (t_1/2 = 2.6E6 yr) iron isotope important for dating stellar events. Deriving the excitation energy from the proton in the (d,pγ) reaction requires precise knowledge of the target thickness when back calculating the longitudinal energy loss. CD₂ target thicknesses were characterized using a 228-Th source and a position-sensitive Dual-Axis Duo-Lateral Si detector. Development of a detector that can separate contaminates from a radioactive ⁵⁹Fe beam (t_1/2 = 45 d) on an event-by-event basis is necessary to measure ⁶⁰Fe’s PSF as accurately as possible is in progress.