Lazic Violeta, Andreoli Fabrizio, Almaviva Salvatore, Pistilli Marco, Menicucci Ivano, Ulrich Christian, Schnürer Frank, Chirico Roberto
Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Laboratory FSN-TECFIS-DIM, Via Enrico Fermi 45, 00044 Frascati, Italy.
Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Laboratory FSN-FUSEN-TEN, Via Enrico Fermi 45, 00044 Frascati, Italy.
Sensors (Basel). 2024 Feb 24;24(5):1469. doi: 10.3390/s24051469.
In this work, we present a compact LIBS sensor developed for characterization of samples on a crime scene following requirements of law enforcement agencies involved in the project. The sensor operates both in a tabletop mode, for aside measurements of swabbed materials or taken fragments, and in handheld mode where the sensor head is pointed directly on targets at the scene. The sensor head is connected via an umbilical to an instrument box that could be battery-powered and contains also a color camera for sample visualization, illumination LEDs, and pointing system for placing the target in focus. Here we describe the sensor's architecture and functionalities, the optimization of the acquisition parameters, and the results of some LIBS measurements. On nano-plotted traces at silica wafer and in optimized conditions, for most of the elements the detection limits, in term of the absolute element masses, were found to be below 10 picograms. We also show results obtained on some representative materials, like fingerprints, swabbed soil and gunshot residue, varnishes on metal, and coated plastics. The last, solid samples were used to evaluate the depth profiling capabilities of the instrument, where the recognition of all four car paint layers was achieved.
在这项工作中，我们展示了一种紧凑的激光诱导击穿光谱（LIBS）传感器，它是根据参与该项目的执法机构的要求开发的，用于对犯罪现场的样本进行表征。该传感器既可以在桌面模式下运行，用于对擦拭材料或采集的碎片进行侧面测量，也可以在手持模式下运行，此时传感器头直接对准现场的目标。传感器头通过脐带电缆连接到一个仪器箱，该仪器箱可以由电池供电，还包含一个用于样本可视化的彩色相机、照明发光二极管以及用于将目标聚焦的指向系统。在此，我们描述了传感器的架构和功能、采集参数的优化以及一些LIBS测量的结果。在二氧化硅晶片上的纳米绘制痕迹以及优化条件下，对于大多数元素，就绝对元素质量而言，检测限被发现低于10皮克。我们还展示了在一些代表性材料上获得的结果，如指纹、擦拭的土壤和枪击残留物、金属上的清漆以及涂层塑料。最后，使用固体样品来评估该仪器的深度剖析能力，实现了对汽车所有四层漆层的识别。
