Application Of Reheating Orthogonal Dual-Pulse Laser-Induced Breakdown Spectroscopy In Elemental Mapping Analysis

The natural quartzite jade has abundant colors,and its color enrichment is mainly related to the distribution of iron and other trace elements.Therefore,by studying the distribution and content of trace chromogenic elements such as iron in jade samples,it can be meaningful to judge the gemological characteristics,species and commercial value of jade samples,and the research results can be applied to the identification of jade or other fields.In this paper,laser induced breakdown spectroscopy(LIBS)was used to analyze the elemental distribution of natural jade by scanning imaging.Owing to the characteristic of the LIBS device,we don't need to or only need to slightly process the samples and don't need to isolate the samples when carrying out the experiment of scanning the elemental distribution of jade.Because the experiment device is simple,LIBS can be used for real-time and in situ detection,which reduces the difficulty and cost of the sample elemental distribution mapping analysis.When the single-pulse LIBS technology is used for the distribution mapping analysis of trace elements in jade samples,the detected sensitivity is always low.In order to improve the detected sensitivity and improve the quality of elemental distribution mapping analysis,dualpulse LIBS can be used for enhancement.The reheating orthogonal dual-pulse laser-induced breakdown spectroscopy technique used in the experiment in this paper is a relatively suitable way to improve the sensitivity of elemental distribution analysis.The orthogonal structure can increase the detected signal value under the condition that it causes the same damage to the sample as the single pulse LIBS.In this study,first of all,experiments were carried out to get the temporal profiles of plasma emission of quartzite jade by single-pulse LIBS and dual-pulse LIBS.By comparison,dual-pulse LIBS could achieve a signal to background ratio improvement of about 8 times compared with single-pulse LIBS under this experimental condition.Then,the effects of pulse interval and laser energy on the atomic signal intensity were studied,and the experimental conditions for obtaining the best intensity effect were recorded.Then under the best experimental conditions,two-dimensional elemental mapping analysis was carried out on the surface of natural jade sample within the scope of 36 mm ×10mm,and the twodimensional distribution images of the trace element Fe on the surface of jade sample(ablation pit diameter is about 30 ?m)was obtained through the self-developed software.The experimental results show that iron,copper and other trace elements in natural jade samples can be detected effectively by means of orthogonal dual-pulse laser induced breakdown spectroscopy.In addition,compared with the single-pulse laser-induced breakdown spectroscopy,the detected sensitivity can be improved under the same sample damage condition.This technique can not only analyze the surface elemental distribution of jade samples and provide reference for the identification of jade,but also can be applied to the scanning mapping analysis of two-dimensional elemental distribution of other solid samples which will have nice-application prospects.