Real-time monitoring of ion source plasma using optical emission spectroscopy

Optical emission spectroscopy has been used to monitor in real-time the inductively coupled RF plasma in the ULE2 ion source. A model has been developed to correlate optical spectra from the source taken in the near-UV, visible, and near-IR regions of the spectrum with extracted ion beam constituents. Emission from atomic, ionic, and molecular lines and bands is used to develop the model. Neural network algorithms are used to assist in this development. The model shows good agreement with experimental results for all ion species extracted in beams run with BF/sub 3/, PH/sub 3/, AsH/sub 3/, and GeF/sub 4/ source gases. Complete beam mass spectra can be predicted using only the optical spectra and used to aid in source tuning or cleaning procedures.