Solar Energetic Particles from the 6 November 1997 solar flare/CME(coronal
mass ejection) with energies exceeding 10 GeV have been detected by Milagrito,
a prototype of the Milagro Gamma Ray Observatory. While particle acceleration
beyond 1 GeV at the Sun is well established, few data exist for protons or ions
beyond 10 GeV. The Milagro observatory, a ground based water Cherenkov detector
designed for observing very high energy gamma ray sources, can also be used to
study the Sun. Milagrito, which operated for approximately one year in 1997/98,
was sensitive to solar proton and neutron fluxes above ~5- 10 GeV. Milagrito
operated in a scaler mode, which was primarily sensitive to muons, low energy
photons, and electrons, and the detector operated in a mode sensitive to
showers and high zenith angle muons. In its scaler mode, Milagrito registered a
rate increase coincident with the 6 November 1997 ground level event observed
by Climax and other neutron monitors. A preliminary analysis suggests the
presence of >10 GeV particles.
