How neutron upscattering can enhance the triple alpha reaction

The neutron inelastic scattering of carbon-12, populating the Hoyle state, is a reaction of interest for the triple-alpha process. The inverse process (neutron upscattering) can enhance the Hoyle state’s decay rate to the bound states of ¹²C, effectively increasing the overall triple-alpha reaction rate. Neutron upscattering involves a low-energy neutron interacting with a resonant state and allowing additional de-excitation paths by taking away some of the excess energy as kinetic energy in the neutron. The cross section of this reaction is impossible to measure experimentally but has been determined here at astrophysically-relevant energies using detailed balance. Using a highly-collimated monoenergetic beam, we measured neutrons incident on the Texas Active Target Time Projection Chamber (TexAT TPC) filled with CO₂ gas, measuring the 3α-particles (arising from the decay of the Hoyle state following inelastic scattering) and a cross section was extracted. The results of this recently-published work will be discussed.