A New Feed for the Allen Telescope Array and the Science That it Will Enable

The current feeds of the antennas in the Allen Telescope Array are somewhat unusual and provide wide bandwidth and good sensitivity.  We have recently developed an upgrade to the feed which has even more bandwidth and, equally important, substantially better sensitivity.  The new sensitivity is about as good as can be achieved.  We describe the steps to the upgrade and then lay out new science that is enabled by it, including SETI and the structure of both the nearby and distant universe.