Extraction of Gamow-Teller strengths in the β+ direction with the ( d,He2 ) reaction in inverse kinematics

The (d,²He) reaction in inverse kinematics has been developed for experiments with rare-isotope beams to constrain electron-capture rates needed for astrophysical simulations of processes in dense nuclear environments such as supernovae and neutron star crusts. The first experiment focused on the measurement of the ¹⁴O(d,²He) and ¹³N(d,²He) reactions in inverse kinematics, utilizing the active-target time-projection chamber placed in front of the S800 magnetic spectrograph. This work focuses on the experimental and analysis details, and presents the results for the ¹³N(d,²He) reaction, which is important for constraining electron captures rates on ¹³N in the preexplosion convective phase of Type Ia supernova. The extracted Gamow-Teller transition strengths associated with electron capture on ¹³N are consistent with those previously obtained from the analog transitions from ¹³C. The successful development of the (d,²He) reaction in inverse kinematics presents a novel opportunity for performing experiments aimed at constraining electron-capture rates in nuclei far from stability.