  Above tens of GeV, gamma-ray observations with the Fermi Large Area Telescope
(LAT) can be dominated by statistical uncertainties due to the low flux of
sources and the limited acceptance. We are developing a new event class which
can improve the acceptance: the "Calorimeter-only (CalOnly)" event class. The
LAT has three detectors: the tracker, the calorimeter, and the anti-coincidence
detector. While the conventional event classes require information from the
tracker, the CalOnly event class is meant to be used when there is no usable
tracker information. Although CalOnly events have poor angular resolution and a
worse signal/background separation compared to those LAT events with usable
tracker information, they can increase the instrument acceptance above few tens
of GeV, where the performance of Fermi-LAT is limited by low photon statistics.
In these proceedings we explain the concept and report some preliminary
characteristics of this novel analysis.
