CHARACTERISTIC TEMPERATURES IN A FAPES SOURCE

A number of state distribution temperatures were measured in an effort to characterize a 100 W 13.56 MHz rf He plasma established in a FAPES (Furnace Atomization Plasma Emission Spectrometry) source. Excitation temperatures derived from a Boltzmann plot of He I and Fe I lines were in reasonable agreement, i.e. 3300 +/- 180 and 2920 +/- 180 K, respectively. An excitation temperature measured with Fe II lines was substantially larger than the above values, being 7610 +/- 450 K. A kinetic or Doppler temperature based on measurement of the width of the Be I 234.861 nm line profile was 7030 +/- 1150 K whereas the He ionization temperature derived from the measured electron number density was 10920 +/- 1900 K. It is clear that complete LTE does not exist in this source.