在激光诱谱导击穿光谱技术(laser-induced breakdown spectroscopy, LIBS)中, 元素特征光谱信号强度和信噪比在不同采集延时下具有显著差异, 直接影响定量分析的结果。 LIBS分析系统通常采用通用型延时发生器来控制采集延时, 然而其体积大、 功耗高、 价格昂贵, 不利于LIBS仪器的小型化和便携化。 为此, 采用单片微控制器芯片和简单外围电路设计实现了具有55 ps可调延时精度的多通道微型同步时序发生器(简称LDG30), 大幅度降低了同步时序发生器的体积、 功耗和成本。 对比LDG30与一种典型通用延时发生器DG535作为同步时序发生器的LIBS系统, 以钒钛生铁中微量钒(V)元素定量检测为例进行两种同步时序发生器性能分析。 结果表明, 采用LDG30和DG535的LIBS系统建立的V元素定标曲线拟合系数R2均大于0997, 前者的平均相对标准偏差ARSD略小于后者, 达到228%; 前者检测极限LoD略低于后者, 达到1990 μg·g-1。 因此, 自主设计的同步时序发生器LDG30与DG535在LIBS系统中的精度基本一致, 完全满足LIBS系统的实际控制和集成应用需求, 特别适合于体积与功耗受限的LIBS仪器。

The intensities and signal-to-noise ratios(SNRs)of characteristic spectrum are remarkably different under disparate delay times in Laser-Induced Breakdown Spectroscopy(LIBS), which affects the performance of quantitative analysis directly. Conventionally, the general digital delay generator is used to control the delay time in LIBS, butit’s not suitable for compact LIBS equipmentsdue to its large size, high power and high price. In this study, a compact synchronizer (LDG30) with 55 ps resolution was designed and built by using a microcontroller unit and simple circuits. The LDG3. 0 had a considerably smaller size, lower power and lower price than a general digital delay generator DG535. Quantitative analysis of V element in iron samples was investigated to compare the performance of LDG30 and DG535 in LIBSsystem. The results showed that the two LIBS systems with LDG30 and DG535 had almost the same calibration curve of V, and the determination coefficient R2 were both above 0997. The average relative standard deviation(RSD) of V by LIBS system with LDG30 was 228% which slightly smaller than LIBS system with DG535, and the limit of detection (LoD) of the former was 1990 μg·g-1 which sligthly below the latter. Therefore, the self-builtsynchronizer LDG30 has approximately the same accuracy with DG535 in LIBS systemand meets the control and integration requirements of LIBS. The LDG30 is especially suitable for compact LIBS instruments.