EGRET observations of X-class solar flares

A series of X-class solar flares in the first week of June from the same region of the Sun prompted the action of making the Sun a Target of Opportunity for the Compton Observatory. The high energy capabilities of the EGRET instrument provided an opportunity to investigate the energetic solar flare processes for these flares. During the June 11, 1991 flare, the EGRET spark chamber obtained spectral and temporal measurements of high energy gamma-ray emissions to greater than 1 GeV lasting hours after the initial impulsive phase of the flare. Spectral fits of the spark chamber data allow bremsstrahlung and pion decay contributions to the extended delayed emission to be determined. Spectral fits of the EGRET Nal data for the 1-200 MeV energy range allow the solar line fluences of the 2.23 and 4.43 MeV radiation to be determined for four of the June flares. Another series of X-class flare that occurred in late October 1991 were observed by the EGRET Nal detector and similar analyses were performed.