The study of the 27Al(α,p) reaction using the upgraded ANASEN detector

The Array for Nuclear Astrophysics and Structure with Exotic Nuclei (ANASEN) is an active target detector optimized to study (α,p) reactions [1]. These reactions, which are important to many astrophysical scenarios, have large uncertainties in their reaction rates due to a lack of direct measurements. ANASEN is designed for use in RIB facilities and is capable of handling high beam rates in the range of 10⁶ pps. This high-rate capability promises to achieve sensitivity high enough for measurements in the Gamow window of 1 GK and at sub-mBarn cross-sections. ANASEN has recently been upgraded with a twisted wire proportional counter aimed at improving the position resolution. This new detector has been commissioned and was recently used for a stable beam experiment in the study of the 27Al(α,p) reaction. The reaction is important for the study of core-collapse supernovae as it influences the Ye and eventually the production of 56Ni in these events[2]. Results from the experiment will be discussed.

[1] Koshchiy, E., J.C. Blackmon, G.V. Rogachev, I. Wiedenhöver, L. Baby, P. Barber, D.W. Bardayan, et al. “ANASEN: The Array for Nuclear Astrophysics and Structure with Exotic Nuclei.” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 870 (October 2017): 1–11. https://doi.org/10.1016/j.nima.2017.07.030.

[2] Subedi, Shiv K., Zach Meisel, and Grant Merz. “Sensitivity of 44Ti and 56Ni Production in Core-Collapse Supernova Shock-Driven Nucleosynthesis to Nuclear Reaction Rate Variations.” The Astrophysical Journal 898, no. 1 (July 2020): 5. https://doi.org/10.3847/1538-4357/ab9745