Optical emission spectra of a copper plasma produced by a metal vapour vacuum arc plasma source

Optical emission spectroscopy in the range 200-800 nm was applied for inves tigation of the copper plasma produced by a metal vapour vacuum arc plasma source. The experiments were conducted for the cases when the plasma was gu ided by straight and Ohm -shaped curved solenoids as well as without soleno ids, and also for different vacuum conditions. It was found that, besides s ingly- and doubly-charged ions, a relatively high concentration of excited neutral copper atoms was present in the plasma. The relative fraction of ex cited atoms was much higher in the region close to the cathode surface than in the plasma column inside the solenoid. The concentration of excited neu tral. singly- and doubly-ionized atoms increased proportionally when the ar c current was increased to 400 A. Some weak lines were attributed to more h ighly ionized copper species and impurities in the cathode material.