Absolute determination of theNa22(p,γ)

Outstanding problems in nuclear astrophysics: recent progress at TRIUMF

“…This reaction had never been measured and therefore contributed a large uncertainty to the final 22 Na and 26 Al predicted yields in nova models. With the highest intensity accelerated 23 Mg beam in the world, some 5 × 10 7 s −1 , the 23 Mg(p, γ ) 24 Al reaction was measured directly for the first time at the DRAGON facility to a precision sufficient for nova yield purposes.…”

“…Part of the problem again is nuclear physics uncertainties in 22 Na production and destruction reactions. 26 Al is unsuitable for observation from a single source because of its long lifetime, but novae are thought to produce up to 20% of the 26 Al observed in the galaxy, with the rest coming from massive stars.…”

“…A reaction that affects the abundance of both 22 Na and 26 Al in novae is 23 Mg(p, γ ) 24 Al. This reaction had never been measured and therefore contributed a large uncertainty to the final 22 Na and 26 Al predicted yields in nova models.…”

“…If hot enough, nucleosynthesis involving proton capture reactions can occur up to the calcium region. In addition, long-lived radionuclides such as 18 F, 22 Na and 26 Al are synthesized. These radionuclides are observation targets for satellite γ ray telescope missions, and could provide a powerful tool to observe and understand nova explosions.…”

“…Subsequently the 22 Na(p, γ ) 23 Mg reaction was measured using this target and a proton beam from the accelerator at CENPA. 25,26 Strengths of all known resonances were re-measured with the highest precision to date, as was the potential new resonance. It was found that some of the previously measured resonances were in fact some 2.5-3 times stronger.…”