The Origin of Oxygen in the Universe - A new approach to an Old Question

Carbon and oxygen are not only important elements for the existence of life on Earth, but they also play an important role in the evolution of stars towards the end of their life cycle. The formation of ¹²C through the so-called triple-α reaction is quite well understood. The next step, the formation of ¹⁶O through the a capture reaction ¹²C(α, γ)¹⁶O on the other hand, still has an experimental uncertainty of ∼ 30%. Direct measurements of the ¹²C(α, γ)¹⁶O reaction by detecting either the outgoing γ radiation in a high acceptance Ge-detector array or the residual ¹⁶O nuclei in a mass spectrometer do not allow for order-of-magnitude improvements. In this contribution, the possibility of using superheated bubble detectors for a measurement of the time-inverse ¹⁶O(γ, α)¹²C reaction is being discussed. The first results of a 'proof-of-principle' experiment of the ¹⁹F(γ, α)¹⁵N reaction are also being presented.