Search for 1.809 MeV Emission of 26Al from nearby Supernova Remnants   using COMPTEL
  We report the negative results of our searches in COMPTEL data for 1.809 MeV gamma-ray line emission from four localized regions which contain nearby supernova remnants (SNRs). The upper flux limits (2 Sigma) are found to be in the range of 1.4*10e-5 to 2.4*10e-5 photons/s/cm/cm. These upper limits do not severely constrain the theoretical 26Al yields from individual core collapse supernovae due to large uncertainties in the SNR distances and the nature of the progenitor stars. 
Juergen Knoedlseder, Uwe Oberlack, Roland Diehl, Wan Chen, and Neil   Gehrels