激光共振电离质谱用钚源的制备及探测效率测定

为提高激光共振电离质谱（LRIMS）中钚的原子化效率，设计制备了金属包覆钚源，以期提高LRIMS测量痕量钚的灵敏度。本工作设计加工了适用于痕量钚制源的电沉积装置，研究了水相中痕量钚的电沉积条件，实现了痕量钚的定量电沉积；对比研究了金属铂和钛的电镀条件及性能，确定了以钛为包覆层的真空蒸镀条件，实现了镀层厚度为1 μm、金属钛包覆的高效钚源中钚的总沉积率达95%。研究表明，制备的高效钚源经过LRIMS测试，仪器对钚样品的总探测效率为2.5×10^-4，原子化效率提高至7.7%，较直接滴加源提高3个数量级，为LRIMS法高灵敏测量环境中痕量钚奠定了基础。

Preparation of Pu Source for Laser Resonance Ionization Mass Spectrometer and Determination of Detection Efficiency

To get higher atomization efficiency of Pu used for laser resonance ionization mass spectrometer (LRIMS) which can improve the sensitivity of trace Pu measured by mass spectrometry, Pu source covered with metal was made by electrodeposition. The quantitative electrodeposition of Pu was achieved by designing an electrodepositor and optimizing electrodeposition conditions. Compared with Pt coating, a Ti coating was prepared by vacuum evaporation, and the thickness of which is 1 μm. The whole deposition rate of Pu is above 95%. The total detection efficiency of LRMIS for Pu is 2.5×10^-4, and the atomization efficiency of Pu source coated by Ti is 7.7%, which are three orders of magnititude higher than direct drop source. This lays the foundation for analysis of trace amounts of Pu in the environment by LRIMS with high sensitivity.