https://spdf.gsfc.nasa.gov/pub/data/ibex/release3/lo/maps/digital_data/release_3/angulardata/aareadme

see the IBEX team's detailed documentation and links to relevant science papers at

https://spdf.gsfc.nasa.gov/pub/data/ibex/release3/Data_Release_3/IGFP_paper_data/IGFP_paper_desc.pdf
http://ibex.swri.edu/ibexpublicdata/Data_Release_3/