DETERMINATION OF THE GALACTIC AL-26 SOURCE DISTRIBUTION WITH A NOVEL IMAGING TELESCOPE

An instrument is described which will provide a direct image of gamma- ray line or continuum sources in the energy range 300 keV-10 MeV. We i llustrate the use of this instrument to study the celestial distributi on of the Al-26 isotope by observing the 1.809 MeV de-excitation gamma -ray line. The source location accuracy is 2' or better. The imaging t elescope is a liquid xenon time projection chamber coupled with a code d aperture mask (LXeCAT). This instrument will confirm and extend the COMPTEL observations from the Compton Gamma Ray Observatory (CGRO) wit h an improved capability for identifying the actual Galactic source or sources of Al-26, which are currently not known with certainty. Sourc es currently under consideration include red giants on the asymptotic giant branch, novae, Type Ib or Type II supernovae, Wolf-Rayet stars, and cosmic rays interacting in molecular clouds. The instrument could also identify a local source of the celestial 1.809 MeV gamma-ray line , such as a recent nearby supernova.