Electron-impact ionization cross sections for nitrogen molecule from 250 to 8000 eV

The partial and total ionization cross sections for N2 in gas phase by electron impact in a wide energy range have been measured by ion imaging mass spectrometer. The results are put on an absolute scale by normalizing the data of N2+ to that of Ar+ from N2-Ar mixture target. The overall errors are evaluated by considering various kinds of uncertainties. Comparisons are made with the previous measurements.