https://spdf.gsfc.nasa.gov/pub/data/ibex/release3/lo/time_series/histograms/band_3/aareadme.txt

This directory provides 8-day (full IBEX orbit) 
histograms files produced by the IBEX-Lo instrument
in energy band 3.  Energy band 3 is centered at 52 eV.

See the readme files in parent directories, and the 
IBEX team-generated documentation files contained in those
directories.