Figures of merit and physical characteristics of a capacitively coupled radiofrequency argon plasma sustained at atmospheric pressure in tip-ring electrode geometry

This paper provides a description of a spectral source with capacitively co upled radiofrequency plasma (RF CCP), sustained in argon at atmospheric pre ssure in tip-ring electrodes geometry (RF power: 85-275 W; frequency: 27.12 MHz; Ar flow-rate: less than or equal to 11/min). The figures of merit wer e determined for atomic emission of pneumatically nebulized liquid samples and for directly sputtered conductive solid samples. Some physical paramete rs (excitation and ionization temperatures and electron number densities) w ere also determined. Colligations were made between the figures of merit of the spectral source, its physical characteristics and the operating condit ions (RF power, Ar flow-rate and distance between electrodes). The excitati on temperatures for Ar were in the range of 1800-3700 K and for FeI between 3700-4700 K, the ionization temperature for Ca was between 4400-4650 K and the electron number density was determined to be in the range of 3-5x10(14 ) cm(-3). The detection limits for 19 elements (Li, Na, Eu, Ca, Pb, Fe, Ni, Co, Ag, Cu, Mg, Hg, Cd, Zn, Ba, V, Cr, Mn, Mo) from liquid samples are in the range of 9-5700 ng/ml. For solid samples the detection limits were dete rmined to be in the range of 0.001-0.048 % for 8 elements (Al, Co, Cr, Cu, Mn, Mo, Ni, V) from low or medium alloyed steel samples. The figures of mer it for this new spectral source are compared with those of ICP and CMP.