  The Fermi-Large Area Telescope (LAT) detection of the X8.2 GOES class solar
flare of 2017 September 10 provides for the first time observations of a long
duration high-energy gamma-ray flare associated with a Ground Level Enhancement
(GLE). The >100 MeV emission from this flare lasted for more than 12 hours
covering both the impulsive and extended phase. We present the localization of
the gamma-ray emission and find that it is consistent with the active region
(AR) from which the flare occurred over a period lasting more than 6 hours
contrary to what was found for the 2012 March 7 flares. The temporal variation
of the proton index inferred from the gamma-ray data seems to suggest two
phases in acceleration of the proton population. Based on timing arguments we
interpret the second phase to be tied to the acceleration mechanism powering
the GLE, believed to be particle acceleration at a coronal shock driven by the
CME.
