SPATIAL-DISTRIBUTION OF HE METASTABLE ATOMS IN ELECTRON-CYCLOTRON-RESONANCE PLASMA

Axial profile of HeI metastable (2(1)S) atom density was measured alon g an electron cyclotron resonance (ECR) plasma flow for plasma process ing by polarized laser-induced fluorescence (LIF) spectroscopy. A new development in the LIF method was made to avoid laser stray light, whi ch involved observation of fluorescence due to forbidden excitation by electric quadrupole transition. It was found that the metastable (2(1 )S) atom density produced was as high as 10(11)cm(-3) near the outlet of the plasma flow. Doppler profiles of the LIF excitation were measur ed to determine drift velocity of atoms in the plasma. The production mechanism of metastable atoms was briefly discussed.