Benchmark cross sections for electron-impact total single ionization of helium

We establish the total single ionization cross section for electron-impact ionization of helium, to an accuracy of few per cent, from near threshold to 1 keV. This is done fully ab initio using the convergent close-coupling method without the often-used frozen-core approximation. We find excellent agreement with the most recent measurements of Rejoub et al (2002 Phys. Rev. A 65 042713) and Sorokin et al (2004 J. Phys. B: At. Mol. Opt. Phys. 37 3215), which are around 5% less than the previously used standard.