Gold fineness measurement using single-shot spark assisted laser-induced breakdown spectroscopy

Here, a homemade gold fineness analyzer is fabricated based on calibration-free spark assisted laser-induced breakdown spectroscopy (CF SA-LIBS). The experimental arrangement consists of a Q-switched Nd:YAG laser combined with a spark generator and a single-channel CCD spectrometer. The well-arranged optical system, coupled with an electrical setup, allows us to successfully run SA-LIBS even at low energy single shots. The electric discharge contributes LIBS to reheat and promote more energetic plasma. Subsequently, plasma temperature elevates up to similar to 20%, and its lifetime is elongated as much as 6 times. As a consequence, the relative signal intensity is enhanced up to 1 order of magnitude against that of LIBS at the same pulsed energy. Furthermore, the electron density is also measured based on the broadened spectral width of the intensified H alpha line. The latter is used to obtain the ionic species concentrations more accurately according to the Saha-Eggert equation. As a result, we have assessed the gold karat with an analytical error less than 0.5% using CF SA-LIBS. In addition, the surface patterns recorded by the stylus profilometer reveal that the single-shot SA-LIBS benefits a smaller ablative mass against standard LIBS. (C) 2021 Optical Society of America

Automated summary

In this study, a homemade gold fineness analyzer based on CF SA-LIBS was fabricated, showing enhanced relative signal intensity by 1 order of magnitude. The technique allows for more accurate determination of ionic species concentrations, resulting in analytical errors of less than 0.5% for gold karat assessment. Additionally, single-shot SA-LIBS benefits from smaller ablative mass compared to standard LIBS.