Destruction of the cosmic γ-ray emitter 26Al in massive stars: Study of the key 26Al(n, α) reaction

We thank P. Black (University of Edinburgh) for support in design and construction of the detection system and P. Morrall (Daresbury Laboratory) for production of the B and LiF reference samples. This Letter was supported by the Austrian Science Fund (FWF), Project No. J3503, by JRCIRMM through the EUFRAT Program, by the U.K. Science and Technologies Facilities Council (STFC), Projects No. ST/L005824/1 and No. ST/M006085/1, the European Research Council ERC-2015-STG Grant No. 677497, and the Cost Action "ChETEC" (Grant No. CA16117).Neutron destruction reactions of the cosmic γ -ray emitter 26Al are of importance to determine the amount of 26Al ejected into our galaxy by supernova explosions and for 26Al production in asymptotic giant branch stars. We performed a new measurement of the 26Al(n, α) reaction up to 160-keV neutron energy at the neutron time-of-flight facilities n_TOF at CERN and GELINA at EC-JRC. We provide strengths for ten resonances, six of them for the first time. We use our data to calculate astrophysical reactivities for stellar temperatures up to 0.7 GK. Our results resolve a discrepancy between the two previous direct measurements of this reaction, and indicate higher stellar destruction rates than the most recently recommended reactivity.Austrian Science Fund (FWF) J3503JRCIRMM through the EUFRAT ProgramUK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC) ST/L005824/1 ST/M006085/1European Research Council (ERC)European Commission 677497Cost Action "ChETEC" CA1611