Level structure of Si26 and its implications for the astrophysical reaction rate of Al25(p,γ)Si26

A study of the level structure of Si26 using in-beam γ-ray spectroscopy is presented. A full level scheme is derived incorporating all states lying below the proton threshold energy. The results are in good agreement with shell model predictions and one-to-one correspondence is found with states in the mirror nucleus Mg26. Additionally, a γ-decay branch is observed from a state at 5677.0(17) keV, which is assigned to a 1+ resonance important in the astrophysical reaction Al25(p,γ)Si26. The newly derived resonance energy, Er=159.2(35) keV, has the effect of decreasing the reaction rate at the novae ignition temperature of 0.1 GK by a factor of 2 when compared with the previous most precise measurement of this state

Level structure of 22Mg: Implications for the22Na(p, γ)22Mg astrophysical reaction rate and for the22Mg mass

The level structure of 22Mg has been studied with high-sensitivity γ-ray spectroscopy techniques. A complete level scheme is derived incorporating all subthreshold states and all levels in the energy region relevant for novae burning. The excitation energy of the most important astrophysical resonance is measured with improved accuracy and found to differ from previous values. Combining the present result with a recent resonance energy measurement of this state leads to a derived 22Mg mass excess of -400.5(13) keV

Three-dimensional computational analysis of transport phenomena in a PEM fuel cell

Udgivelsesdato: 1. apri