Photoionization of helium, neon and argon in the 60-230 eV photon energy range

The photoionization absorption coefficients of helium, neon and argon have been measured by single beam photometry in the 60-230 eV photon energy range using a synchrotron radiation source and channel electron multiplier photodetection. The accuracy of most of the data is +or-3% rising to +or-5% for a few cases in helium. Agreement with theory is typically better than 20% for photon energies up to 150 eV with greater discrepancies at higher energies especially for helium and argon.