TITLE: GeV Solar Energetic Particle Observation and Search by IceTop from
2011 to 2016

ABSTRACT: Only three Ground Level Enhancements (GLEs) produced by GeV
solar energetic particles have been confirmed in the present solar
cycle, and those have been quite small by historical standards. At the
same time direct observations of high energy solar particles from
spacecraft have become available. This has resulted in some discussion
as to whether the definition of a GLE as an event detectable on the
ground (as opposed to a statement about the spectral form of the
event) is an appropriate scientific classification. The combination of
instruments at the Amundsen - Scott Station at the geographic South
Pole offers an opportunity to span the two worlds. Operating at high
altitude and low geomagnetic cutoff the neutron monitor at Pole has
nevertheless traditionally been accepted as making a "ground level"
observation. An enhanced array of bare neutron detectors and IceTop
(the surface component of the IceCube Neutrino Observatory) now allow
spectral information to be extracted from events that are too small to
use geomagnetic techniques to obtain spectra. We report our spectral
measurements for the three confirmed GLEs and compare them to other
available data on these events. We also present preliminary results of
an ongoing study of 34 particle events selected to have significant
enhancements in the > 100 MeV channel in GOES data in terms of
possible detections and sensitivity limits.