To explain the ^(26)Mg isotopic anomaly seen in meteorites (^(26)Al daughter) aswell as the observation of 1809-keV γ rays in the interstellar medium (live decay of26Al) one must know, among other things, the destruction rate of ^(26)Al. Propertiesof states in ^(27)Si just above the ^(26)Al + p mass were investigated to determine thedestruction rate of ^(26)Al via the ^(26)Al(p,γ)^(27)Si reaction at astrophysical temperatures.
Twenty micrograms of ^(26)Al were used to produce two types of Al_2O_3 targetsby evaporation of the oxide. One was onto a thick platinum backing suitable for(p,γ) work, and the other onto a thin carbon foil for the (^3He,d) reaction.
The ^(26)Al(p,γ)^(27)Si excitation function, obtained using a germanium detectorand voltage-ramped target, confirmed known resonances and revealed new ones at770, 847, 876, 917, and 928 keV. Possible resonances below the lowest observedone at E_p = 286 keV were investigated using the ^(26)Al(^3He,d)^(27)Si proton-transferreaction. States in 27Si corresponding to 196- and 286-keV proton resonances wereobserved. A possible resonance at 130 keV (postulated in prior work) was shownto have a strength of wγ less than 0.02 µeV.
By arranging four large Nal detector as a 47π calorimeter, the 196-keV protonresonance, and one at 247 keV, were observed directly, having wγ = 55± 9 and10 ± 5 µeV, respectively.
Large uncertainties in the reaction rate have been reduced. At novae temperatures,the rate is about 100 times faster than that used in recent model calculations,casting some doubt on novae production of galactic ^(26)Al.
