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 illustrate the use of this instrument to study the celestial distribution 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 telescope is a liquid xenon time projection chamber coupled with a coded aperture mask (LXeCAT). This instrument will confirm and extend the COMPTEL observations from the Compton Gamma Ray Observatory (CGRO) with an improved capability for identifying the actual Galactic source or sources of Al-26, which are currently not known with certainty. Sources 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.