Improving the emission intensity of laser-induced breakdown spectroscopy by tip discharge of a Tesla coil

Abstract

This study combined Tesla coil discharge with laser-induced breakdown spectroscopy (TCD-LIBS) to improve the spectral intensity of Cu plasmas. The Tesla coil used a transformer to enhance an ordinary voltage, and then discharged from the discharge terminal of the secondary coil. A DC voltage of 24 V was converted into a high-frequency AC voltage of thousands of volts by the Tesla coil. The voltage, frequency, energy, and current of the generated high voltage AC discharge were 1.66 kV, 1.35 MHz, 24 W, and 14.5 mA. First, the effect of the discharge distance (the discharge tip to the sample surface) on the line intensity was optimized, revealing that the spectral emission of TCD-LIBS was stronger in the distance range from 4 mm to 8 mm. Secondly, the effect of laser energy on the spectral emission with or without discharge was investigated. The spectral intensity can be increased by about 40 times using Tesla coil discharge. Finally, the electron temperature and density of TCD-LIBS were obtained, revealing that the two parameters can be increased by about 1.6 and 1.4 times using Tesla coil discharge. Because the Tesla coil has high spectral enhancement efficiency and safety, the combination of Tesla coil discharge and LIBS is conducive to the development of the LIBS analysis field.