TEMPORAL AND SPECTRAL PROPERTIES OF THE MAY 11, 1990 SOLAR-FLARE (GRANAT DATA)

The high-energy solar flare of May 11, 1990 was associated with the ac tive region no. 6063 and was observed by the PHEBUS instrument of the Granat satellite for similar to 20 min, beginning at 20(h)58(m)9(s), a t energies above 100 keV. The flare of May 24, 1990 from the same acti ve region on the Sun became the brightest solar event over the entire period of the Observatory's in-orbit operation, During the flare SF900 511, both nuclear gamma-ray Lines produced by the excitation of nuclei C-12, O-16 and other elements in the solar atmosphere and the 2.23-Me V Line arising during the capture of neutrons by protons were detected . A comparison of the total luminosity in the nuclear 4-7.2 MeV lines and in the delayed 2.23 MeV line shows that, when described by Bessel' s function, the spectrum of accelerated protons has the parameter alph a T that lies in the range 0.2 < alpha T < 0.3. The peak of the emissi on intensity in 2.23-MeV line is delayed with respect to the peak in t he nuclear lines by similar to 70 s. The e-folding decay time of the 2 .23-MeV Line :intensity during the first 90 s after the peak of its in tensity was 164 +/- 20 s, which made it possible to place an upper lim it on the abundance ratio He-3/H-1 = (4.7 +/- 1.8) x 10(-5).