Determination of the electron energy distribution function via optical emission spectroscopy and a Langmuir probe in an ICP

Optical emission spectroscopy (OES) and Langmuir probe measurements are used to determine the electron density and the electron energy distribution function (EEDF) in an inductively coupled plasma (ICP) intended for sterilization of materials in medical applications. Measuring the EEDF with the Langmuir probe in the ICP discharge is limited to energies below 11 eV. Using OES the EEDF can be determined between 1.5 and 30 eV (in a He : N2 mixture). These methods are reliably compared in an ICP in a He : N2 mixture. Both diagnostics complement one another to determine the EEDF in a wide kinetic energy range.