A measurement of the atmospheric muon neutrino energy spectrum from 100 GeV
to 400 TeV was performed using a data sample of about 18,000 up-going
atmospheric muon neutrino events in IceCube. Boosted decision trees were used
for event selection to reject mis-reconstructed atmospheric muons and obtain a
sample of up-going muon neutrino events. Background contamination in the final
event sample is less than one percent. This is the first measurement of
atmospheric neutrinos up to 400 TeV, and is fundamental to understanding the
impact of this neutrino background on astrophysical neutrino observations with
IceCube. The measured spectrum is consistent with predictions for the
atmospheric muon neutrino plus muon antineutrino flux.
