An electron time-of-flight (TOF) technique was utilized to obtain absolute differential cross sections for electron impact excitation in He, Xe, and CO at near-threshold impact energies at scattering angle. These cross sections are more reliable that those obtained from conventional beam - beam scattering measurements using electrostatic spectrometers and can serve as secondary standards for normalizing relative scattering intensities. The results obtained from the TOF measurements are significant also because they fill the gap between cross sections available at very near threshold and intermediate impact energies.