Lithium-argon discharges in a multicusp-ECR microwave resonant cavity

Argon and lithium-argon discharges have been created in a multicusp-ECR microwave resonant cavity. A double Langmuir probe has been used to determine discharge characteristics, indicating ion densities of 10¹⁰-10¹¹ cm^-3 and electron temperatures of about 3 eV with operating pressures of 4-20 mtorr and input powers of 100-250 W. Lithium is introduced to the system in the form of lithium chloride or lithium carbonate which is then heated by a background argon discharge allowing dissociation of lithium. The dissociation is evidenced by the observation of strong Li-I lines in the discharge using optical emission spectroscopy. LiCl was found to give a strong Li-I optical signal for about 15 min run time whereas Li ₂CO₃ gave lower intensity lines, but for about 60 min run time