The feasibility of direct measurement of the ⁴⁴Ti(α, p)47^V and ⁴⁰Ca(α, p)⁴³Sc reactions in forward kinematics at astrophysically relevant temperatures

Understanding the synthesis of radioactive ⁴⁴Ti in the α-rich freeze-out following core-collapse supernovae may help to better interpret such explosive events. The γ-ray lines from the decay of ⁴⁴Ti have been observed by space-based γ-ray telescopes from two supernova remnants. It is believed that the ⁴⁴Ti(α, p)47V reaction dominates the destruction of ⁴⁴Ti, while the 40Ca(α, p)⁴³Sc reaction removes fuel from the main ⁴⁴Ti production reaction 40Ca(α, γ)⁴⁴Ti. Here we report on a possible technique to determine both reaction rates at astrophysically relevant energies in forward kinematics. The first reaction will be performed using a 1–10MBq ⁴⁴Ti target. Two important concerns are considered to make this study possible: The amount of stable Ti in the radioactive target, which will be prepared via spallation reactions at Paul Scherrer Institute (PSI), and the degree of radioactive contaminations in the experimental setup due to sputtered ⁴⁴Ti atoms after intensive irradiations. Several online and offline measurements in parallel with Monte Carlo simulations were performed to investigate these issues.